National Library of Energy BETA

Sample records for vapor phase epitaxy

  1. AlGaAsSb/GaSb Distributed Bragg Reflectors Grown by Organometallic Vapor Phase Epitaxy

    SciTech Connect (OSTI)

    C.A. Wang; C.J. Vineis; D.R. Calawa

    2002-02-13

    The first AlGaAsSb/GaSb quarter-wave distributed Bragg reflectors grown by metallic vapor phase epitaxy are reported. The peak reflectance is 96% for a 10-period structure.

  2. Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy

    E-Print Network [OSTI]

    Stimulated Emission from As-grown GaN Hexagons by Selective Area Growth Hydride Vapor Phase Epitaxy Engineering and the Photonics Center, Boston University, 8 Saint Mary's St., Boston, MA 02215-2421, USA R hydride vapor phase epitaxy. We found the threshold for bulk stimulated emission to be 3.4 MW cm2

  3. Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Yu, Edward T.

    Scanning Kelvin probe microscopy of surface electronic structure in GaN grown by hydride vapor Engineering and Program in Materials Science and Engineering, University of California at San Diego, La Jolla microscopy is used to image surface potential variations in GaN 0001 grown by hydride vapor phase epitaxy

  4. Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy

    SciTech Connect (OSTI)

    Duc, Tran Thien; Pozina, Galia; Son, Nguyen Tien; Janzén, Erik; Hemmingsson, Carl; Ohshima, Takeshi

    2014-09-08

    Defects induced by electron irradiation in thick free-standing GaN layers grown by halide vapor phase epitaxy were studied by deep level transient spectroscopy. In as-grown materials, six electron traps, labeled D2 (E{sub C}–0.24?eV), D3 (E{sub C}–0.60?eV), D4 (E{sub C}–0.69?eV), D5 (E{sub C}–0.96?eV), D7 (E{sub C}–1.19?eV), and D8, were observed. After 2?MeV electron irradiation at a fluence of 1?×?10{sup 14?}cm{sup ?2}, three deep electron traps, labeled D1 (E{sub C}–0.12?eV), D5I (E{sub C}–0.89?eV), and D6 (E{sub C}–1.14?eV), were detected. The trap D1 has previously been reported and considered as being related to the nitrogen vacancy. From the annealing behavior and a high introduction rate, the D5I and D6 centers are suggested to be related to primary intrinsic defects.

  5. Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride vapor phase epitaxy

    E-Print Network [OSTI]

    Time-resolved photoluminescence studies of free and donor-bound exciton in GaN grown by hydride and Electrical and Computer Engineering and Photonics Center, Boston University, Boston, Massachusetts, 02215 R in unintentionally doped GaN grown by hydride vapor phase epitaxy. Low temperature (4 K), time-integrated PL spectra

  6. Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract--In metal organic vapor phase epitaxy we developed

    E-Print Network [OSTI]

    Wetzel, Christian M.

    Journal of Light Emitting Diodes Vol 2 N0 1, April 2010 1 Abstract-- In metal organic vapor phase epitaxy we developed GaInN/GaN quantum well material suitable for 500 ­ 580 nm light emitting diodes at longer wavelengths. Index Terms-- a-plane GaN, GaInN, Green light emitting diode, m-plane GaN I

  7. Impact of thermal annealing on bulk InGaAsSbN materials grown by metalorganic vapor phase epitaxy

    SciTech Connect (OSTI)

    Kim, T. W.; Mawst, L. J.; Kim, K.; Lee, J. J.; Kuech, T. F.; Wells, N. P.; LaLumondiere, S. D.; Sin, Y.; Lotshaw, W. T.; Moss, S. C.

    2014-02-03

    Two different thermal annealing techniques (rapid thermal annealing (RTA) and in-situ post-growth annealing in the metalorganic vapor phase epitaxy (MOVPE) chamber) were employed to investigate their impact on the optical characteristics of double-heterostructures (DH) of InGaAsSbN/GaAs and on the performance of single-junction solar cell structures, all grown by MOVPE. We find that an optimized RTA procedure leads to a similar improvement in the photoluminescence (PL) intensity compared with material employing a multi-step optimized anneal within the MOVPE reactor. Time-resolved photoluminescence techniques at low temperature (LT) and room temperature (RT) were performed to characterize the carrier dynamics in bulk InGaAsSbN layers. Room temperature carrier lifetimes were found to be similar for both annealing methods, although the LT-PL (16?K) measurements of the MOVPE-annealed sample found longer lifetimes than the RTA-annealed sample (680?ps vs. 260?ps) for the PL measurement energy of 1.24?eV. InGaAsSbN-based single junction solar cells processed with the optimized RTA procedure exhibited an enhancement of the electrical performance, such as improvements in open circuit voltage, short circuit current, fill factor, and efficiency over solar cells subjected to the in-situ MOVPE annealing technique.

  8. Chemical vapor deposition of epitaxial silicon

    DOE Patents [OSTI]

    Berkman, Samuel (Florham Park, NJ)

    1984-01-01

    A single chamber continuous chemical vapor deposition (CVD) reactor is described for depositing continuously on flat substrates, for example, epitaxial layers of semiconductor materials. The single chamber reactor is formed into three separate zones by baffles or tubes carrying chemical source material and a carrier gas in one gas stream and hydrogen gas in the other stream without interaction while the wafers are heated to deposition temperature. Diffusion of the two gas streams on heated wafers effects the epitaxial deposition in the intermediate zone and the wafers are cooled in the final zone by coolant gases. A CVD reactor for batch processing is also described embodying the deposition principles of the continuous reactor.

  9. Vapor phase modifiers for oxidative coupling

    DOE Patents [OSTI]

    Warren, Barbara K. (Charleston, WV)

    1991-01-01

    Volatilized metal compounds retard vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.

  10. Vapor phase modifiers for oxidative coupling

    DOE Patents [OSTI]

    Warren, B.K.

    1991-12-17

    Volatilized metal compounds are described which are capable of retarding vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.

  11. Epitaxial graphene prepared by chemical vapor deposition on single crystal thin iridium films on sapphire

    E-Print Network [OSTI]

    Boyer, Edmond

    Epitaxial graphene prepared by chemical vapor deposition on single crystal thin iridium films 2004, there has been an increasing effort in developing efficient methods for preparing graphene graphene can be prepared, which is favorable for the achievement of high quality graphene; it is also known

  12. The role of polymer formation during vapor phase lubrication...

    Office of Scientific and Technical Information (OSTI)

    The role of polymer formation during vapor phase lubrication of silicon. Citation Details In-Document Search Title: The role of polymer formation during vapor phase lubrication of...

  13. Hot-Wire Chemical Vapor Deposition (HWCVD) technologies: Rapid, controllable growth of epitaxial silicon films

    Energy Innovation Portal (Marketing Summaries) [EERE]

    2013-12-27

    NREL scientists have discovered a unique way to quickly grow epitaxial Si using hot-wire chemical vapor deposition (HWCVD), which holds the potential to greatly decrease costs within the manufacturing of Si substrates.  With NREL’s HWCVD technology, Si material use and costs are dramatically reduced with scalable manufacturing and lower deposition temperatures.  NREL’s unique HWCVD technique can easily be integrated into existing manufacturing processes, allowing...

  14. Optical Probing of metamagnetic phases in epitaxial EuSe

    SciTech Connect (OSTI)

    Galgano, G. D.; Henriques, A. B.; Bauer, G.; Springholz, G.

    2011-12-23

    EuSe is a wide gap magnetic semiconductors with a potential for applications in proof-of-concept spintronic devices. When the temperature is lowered, EuSe goes through sharp transitions between a variety of magnetic phases and is thus described as metamagnetic. The purpose of the present investigation is to correlate the magnetic order to the sharp dichroic doublet, discovered recently in high quality thin epitaxial layers of EuSe, grown by molecular beam epitaxy. We report detailed measurements of the doublet positions and intensities as a function of magnetic field in low temperatures, covering several magnetic phases.

  15. Liquid-phase compositions from vapor-phase analyses

    SciTech Connect (OSTI)

    Davis, W. Jr. ); Cochran, H.D. )

    1990-02-01

    Arsenic normally is not considered to be a contaminant. However, because arsenic was found in many cylinders of UF{sub 6}, including in corrosion products, a study was performed of the distribution of the two arsenic fluorides, AsF{sub 3} and AsF{sub 5}, between liquid and vapor phases. The results of the study pertain to condensation or vaporization of liquid UF{sub 6}. This study includes use of various experimental data plus many extrapolations necessitated by the meagerness of the experimental data. The results of this study provide additional support for the vapor-liquid equilibrium model of J.M. Prausnitz and his coworkers as a means of describing the distribution of various impurities between vapor and liquid phases of UF{sub 6}. Thus, it is concluded that AsF{sub 3} will tend to concentrate in the liquid phase but that the concentration of AsF{sub 5} in the vapor phase will exceed its liquid-phase concentration by a factor of about 7.5, which is in agreement with experimental data. Because the weight of the liquid phase in a condensation operation may be in the range of thousands of times that of the vapor phase, most of any AsF{sub 5} will be in the liquid phase in spite of this separation factor of 7.5. It may also be concluded that any arsenic fluorides fed into a uranium isotope separation plant will either travel with other low-molecular-weight gases or react with materials present in the plant. 25 refs., 3 figs., 6 tabs.

  16. MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION

    E-Print Network [OSTI]

    Faccanoni, Gloria

    . (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method. (,) P pressure law. G. Faccanoni DNS OF LIQUIDE-VAPOR PHASE TRANSITION 6 / 23 #12;Model Numerical Method Vapor = 0 x = 0 = 1Fictive fluid 0 pressure law

  17. Monitoring of vapor phase polycyclic aromatic hydrocarbons

    DOE Patents [OSTI]

    Vo-Dinh, Tuan; Hajaligol, Mohammad R.

    2004-06-01

    An apparatus for monitoring vapor phase polycyclic aromatic hydrocarbons in a high-temperature environment has an excitation source producing electromagnetic radiation, an optical path having an optical probe optically communicating the electromagnetic radiation received at a proximal end to a distal end, a spectrometer or polychromator, a detector, and a positioner coupled to the first optical path. The positioner can slidably move the distal end of the optical probe to maintain the distal end position with respect to an area of a material undergoing combustion. The emitted wavelength can be directed to a detector in a single optical probe 180.degree. backscattered configuration, in a dual optical probe 180.degree. backscattered configuration or in a dual optical probe 90.degree. side scattered configuration. The apparatus can be used to monitor an emitted wavelength of energy from a polycyclic aromatic hydrocarbon as it fluoresces in a high temperature environment.

  18. Structural phase transition in epitaxial perovskite films Feizhou He* and B. O. Wells

    E-Print Network [OSTI]

    Alpay, S. Pamir

    Structural phase transition in epitaxial perovskite films Feizhou He* and B. O. Wells Department and substrate constraint on the phase transitions of perovskite films. In SrTiO3 films, the phase transition, 68.55.Jk, 77.55. f, 77.80. e I. INTRODUCTION Perovskite thin films have received great interest

  19. Hydride vapor phase GaN films with reduced density of residual electrons and deep traps

    SciTech Connect (OSTI)

    Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Yugova, T. G.; Cox, H.; Helava, H.; Makarov, Yu.; Usikov, A. S.

    2014-05-14

    Electrical properties and deep electron and hole traps spectra are compared for undoped n-GaN films grown by hydride vapor phase epitaxy (HVPE) in the regular process (standard HVPE samples) and in HVPE process optimized for decreasing the concentration of residual donor impurities (improved HVPE samples). It is shown that the residual donor density can be reduced by optimization from ?10{sup 17}?cm{sup ?3} to (2–5)?×?10{sup 14}?cm{sup ?3}. The density of deep hole traps and deep electron traps decreases with decreased donor density, so that the concentration of deep hole traps in the improved samples is reduced to ?5?×?10{sup 13}?cm{sup ?3} versus 2.9?×?10{sup 16}?cm{sup ?3} in the standard samples, with a similar decrease in the electron traps concentration.

  20. Gas phase reaction of sulfur trioxide with water vapor

    SciTech Connect (OSTI)

    Kolb, C.E.; Molina, M.J.; Jayne, J.T.; Meads, R.F.; Worsnop, D.R.

    1994-12-31

    Sulfur trioxide (SO3) has long been known to react with water to produce sulfuric acid (H2S04). It has been commonly assumed that the gas phase reaction in the Earth`s atmosphere between SO3 and water vapor to produce sulfuric acid vapor is an important step in the production of sulfuric acid aerosol particles. The kinetics of the gas phase reaction of SO3 with water vapor have previously been studied by Castleman and co-workers, Wang et al and Reiner and Arnold. Each of these studies was carried out in a flow reactor, with the first two studies performed at low pressure (1-10 Torr) and the latter from approx. 30 to 260 Torr. Each of these studies measured SO3 decays over a range of H2O vapor levels, obtaining data consistent with interpreting the reaction of gaseous SO3 and H2O as a bimolecular process. It is not clear why previous experimental studies failed to observe a nonlinear dependence of SO3 consumption on water vapor concentration. It is probable that sufficient water dimer exists in much of the Earth`s atmosphere to allow dimer reactions to participate in sulfuric acid vapor formation.

  1. Growth and characterization of liquid phase epitaxial GaP layers 

    E-Print Network [OSTI]

    Kao, Yung-Chung

    1982-01-01

    Z HSVHd aInbIq BO NOIIVZIHBIDVBVHD GNV KIMO'80 GROWTH AND CHARACTERIZATION OF LIQUID PHASE EPITAXIAL GaP LAYERS A Thesis by YUNG-CHUNG KAO Approved as to style and content by: 04 (Chairman of Comm' tee) (Member) ~a m. December 1982 ABSTRACT... GROWTH AND CHARACTERIZATION OF LIQUID PHASE EPITAXIAL Gap LAYERS. (December 1982) Yung-Chung Kao, B. S. , National Tsing-Hua University Chairman of Advisory Committee: Dr. Ohannes Eknoyan Gallium Phosphide, a compound semiconductor with wide energy...

  2. Vapor Phase Synthesis and Characterization of -FeSi Nanowires

    E-Print Network [OSTI]

    Walsworth, Ronald L.

    Vapor Phase Synthesis and Characterization of - FeSi Nanowires Lian Ouyang, Elizabeth S. Thrall, Mandar M. Deshmukh, and Hongkun Park Over the past decade, one-dimensional inorganic nanostructures have emerged as promising materials for fundamental studies and possible technological applications.[1

  3. Epitaxial growth of aligned AlGalnN nanowires by metal-organic chemical vapor deposition

    DOE Patents [OSTI]

    Han, Jung (Woodbridge, CT); Su, Jie (New Haven, CT)

    2008-08-05

    Highly ordered and aligned epitaxy of III-Nitride nanowires is demonstrated in this work. <1010> M-axis is identified as a preferential nanowire growth direction through a detailed study of GaN/AlN trunk/branch nanostructures by transmission electron microscopy. Crystallographic selectivity can be used to achieve spatial and orientational control of nanowire growth. Vertically aligned (Al)GaN nanowires are prepared on M-plane AlN substrates. Horizontally ordered nanowires, extending from the M-plane sidewalls of GaN hexagonal mesas or islands demonstrate new opportunities for self-aligned nanowire devices, interconnects, and networks.

  4. p-type GaN grown by phase shift epitaxy

    SciTech Connect (OSTI)

    Zhong, M.; Steckl, A. J., E-mail: a.steckl@uc.edu [Department of Electrical Engineering and Computing Systems, University of Cincinnati, Cincinnati, Ohio 45221-0030 (United States); Roberts, J. [Nitronex Corporation, Raleigh, North Carolina 27606 (United States)] [Nitronex Corporation, Raleigh, North Carolina 27606 (United States); Kong, W.; Brown, A. S. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)] [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2014-01-06

    Phase shift epitaxy (PSE) is a periodic growth scheme, which desynchronizes host material growth process from dopant incorporation, allowing independent optimization. p-type doping of GaN with Mg by PSE is accomplished with molecular beam epitaxy by periodic shutter action (in order to iterate between Ga- and N-rich surface conditions) and by adjusting time delays between dopant and Ga shutters. Optimum PSE growth was obtained by turning on the Mg flux in the N-rich condition. This suppresses Mg self-compensation at high Mg concentration and produces fairly high hole concentrations (2.4?×?10{sup 18}?cm{sup ?3})

  5. van der Waals Epitaxy of InAs Nanowires Vertically Aligned on Single-Layer Graphene

    E-Print Network [OSTI]

    ABSTRACT: Semiconductor nanowire arrays integrated vertically on graphene films offer significant-organic vapor-phase epitaxy Hybrid junctions composed of semiconductor nanostruc- tures and graphene havevan der Waals Epitaxy of InAs Nanowires Vertically Aligned on Single-Layer Graphene Young Joon Hong

  6. Electrical performance of phase change memory cells with Ge{sub 3}Sb{sub 2}Te{sub 6} deposited by molecular beam epitaxy

    SciTech Connect (OSTI)

    Boschker, Jos E.; Riechert, Henning; Calarco, Raffaella; Boniardi, Mattia; Redaelli, Andrea

    2015-01-12

    Here, we report on the electrical characterization of phase change memory cells containing a Ge{sub 3}Sb{sub 2}Te{sub 6} (GST) alloy grown in its crystalline form by Molecular Beam Epitaxy (MBE). It is found that the high temperature growth on the amorphous substrate results in a polycrystalline film exhibiting a rough surface with a grain size of approximately 80–150?nm. A detailed electrical characterization has been performed, including I-V characteristic curves, programming curves, set operation performance, crystallization activation at low temperature, and resistance drift, in order to determine the material related parameters. The results indicate very good alignment of the electrical parameters with the current state-of-the-art GST, deposited by physical vapor deposition. Such alignment enables a possible employment of the MBE deposition technique for chalcogenide materials in the phase change memory technology, thus leading to future studies of as-deposited crystalline chalcogenides as integrated in electrical vehicles.

  7. Vapor phase elemental sulfur amendment for sequestering mercury in contaminated soil

    DOE Patents [OSTI]

    Looney, Brian B.; Denham, Miles E.; Jackson, Dennis G.

    2014-07-08

    The process of treating elemental mercury within the soil is provided by introducing into the soil a heated vapor phase of elemental sulfur. As the vapor phase of elemental sulfur cools, sulfur is precipitated within the soil and then reacts with any elemental mercury thereby producing a reaction product that is less hazardous than elemental mercury.

  8. Journal of Crystal Growth 241 (2002) 4550 Boron doping of silicon layers grown by liquid phase epitaxy

    E-Print Network [OSTI]

    2002-01-01

    Energy Systems, Department of Engineering, Australian National University, Acton, 0200, Australia cell approaches, such as the solar cells by liquid phase epitaxy over porous silicon (SCLIPS) process in the source wafer. This mismatch is explained by the gradual removal of boron from our system, most likely

  9. Toward epitaxially grown two-dimensional crystal hetero-structures: Single and double MoS{sub 2}/graphene hetero-structures by chemical vapor depositions

    SciTech Connect (OSTI)

    Lin, Meng-Yu [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Chang, Chung-En [Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan (China); Wang, Cheng-Hung [Institute of Display, National Chiao-Tung University, Hsinchu, Taiwan (China); Su, Chen-Fung; Chen, Chi [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Lee, Si-Chen [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Lin, Shih-Yen, E-mail: shihyen@gate.sinica.edu.tw [Graduate Institute of Electronics Engineering, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Department of Photonics, National Chiao-Tung University, Hsinchu, Taiwan (China)

    2014-08-18

    Uniform large-size MoS{sub 2}/graphene hetero-structures fabricated directly on sapphire substrates are demonstrated with layer-number controllability by chemical vapor deposition (CVD). The cross-sectional high-resolution transmission electron microscopy (HRTEM) images provide the direct evidences of layer numbers of MoS{sub 2}/graphene hetero-structures. Photo-excited electron induced Fermi level shift of the graphene channel are observed on the single MoS{sub 2}/graphene hetero-structure transistors. Furthermore, double hetero-structures of graphene/MoS{sub 2}/graphene are achieved by CVD fabrication of graphene layers on top of the MoS{sub 2}, as confirmed by the cross-sectional HRTEM. These results have paved the possibility of epitaxially grown multi-hetero-structures for practical applications.

  10. Electronic phase diagram of epitaxial La{sub 1?x}Sr{sub x}FeO{sub 3} films

    SciTech Connect (OSTI)

    Xie, Y. J.; Scafetta, M. D.; Moon, E. J.; Krick, A. L.; Sichel-Tissot, R. J.; May, S. J.

    2014-08-11

    The electronic phase diagram of epitaxial La{sub 1?x}Sr{sub x}FeO{sub 3} films is presented. The films were grown on SrTiO{sub 3} using molecular beam epitaxy with post-growth annealing to minimize oxygen vacancies. Insulating behavior is observed from x?=?0–0.9, with metallic conduction only present for x?=?1.0. While the La-rich compounds exhibit polaron conduction over all temperatures measured, the Sr-rich films exhibit an electronic phase transition within the compositional window of x?=?0.49–0.9 as revealed by temperature-dependent resistivity measurements. The transition temperatures are found to decrease with increasing Sr content. The constructed phase diagram is discussed in the context of other 3d e{sub g} perovskite systems including manganites and cobaltites.

  11. Vapor-Phase Metalation by Atomic Layer Deposition in a Metal-Organic Framework

    E-Print Network [OSTI]

    Vapor-Phase Metalation by Atomic Layer Deposition in a Metal- Organic Framework Joseph E. Mondloch introduce a new synthetic strategy capable of metallating MOFs from the gas phase: atomic layer deposition and in some instances host- guest interactions may lead to unstable metal@MOFs. Atomic layer deposition (ALD

  12. Engineering work plan for tank 241-C-103 vapor phase characterization (ECN 613188). Revision 1

    SciTech Connect (OSTI)

    Conrad, R.B.

    1994-10-05

    The tasks described by this work plan have been completed. The purpose of this revision it to document what actually occurred during the performance of this work plan. The scope was and is limited to phases 1 and 2 as described in the program plan, revision 1. Phases 1 and 2 include the tank 241-C-103 (C-103) vapor. For economic and as low as reasonably achievable (ALARA) reasons, we will limit our scope to characterize the C-103 vapor phase for the categories that could be expected to impact facility worker safety from a toxicological and flammability standpoint. In anticipation that a vapor treatment system may be required, categories necessary for design will also be included. It will be the intent of the C-103 vapor characterization program to: (1) identify the substances from the above list of categories that are applicable to the issues involving C-103, and (2) implement a phased plan which will develop the organic vapor phase characterization method and then characterize the organics and the other selected substances to the required quantitative certainty.

  13. Chirality-Dependent Vapor-Phase Epitaxial Growth and Termination of Single-Wall Carbon Nanotubes

    E-Print Network [OSTI]

    Zhou, Chongwu

    cylinders from graphene sheets.1 The structure of a SWCNT is uniquely determined by a pair of integers, (n and optical characteristics of SWCNTs rely on their chiralities,2,3 and chirality-controlled preparation

  14. Photoconduction efficiencies and dynamics in GaN nanowires grown by chemical vapor deposition and molecular beam epitaxy: A comparison study

    SciTech Connect (OSTI)

    Chen, R. S. [Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Tsai, H. Y. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Huang, Y. S. [Graduate Institute of Electro-Optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chen, Y. T. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Chen, L. C. [Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Chen, K. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

    2012-09-10

    The normalized gains, which determines the intrinsic photoconduction (PC) efficiencies, have been defined and compared for the gallium nitride (GaN) nanowires (NWs) grown by chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). By excluding the contributions of experimental parameters and under the same light intensity, the CVD-grown GaN NWs exhibit the normalized gain which is near two orders of magnitude higher than that of the MBE-ones. The temperature-dependent time-resolved photocurrent measurement further indicates that the higher photoconduction efficiency in the CVD-GaN NWs is originated from the longer carrier lifetime induced by the higher barrier height ({phi}{sub B} = 160 {+-} 30 mV) of surface band bending. In addition, the experimentally estimated barrier height at 20 {+-} 2 mV for the MBE-GaN NWs, which is much lower than the theoretical value, is inferred to be resulted from the lower density of charged surface states on the non-polar side walls.

  15. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    SciTech Connect (OSTI)

    Dugger, Michael T.; Asay, David B.; Kim, Seong H.

    2008-01-01

    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  16. Condensed phase conversion and growth of nanorods and other materials instead of from vapor

    DOE Patents [OSTI]

    Geohegan, David B. (Knoxville, TN); Seals, Roland D. (Oak Ridge, TN); Puretzky, Alex A. (Knoxville, TN); Fan, Xudong (Oak Ridge, TN)

    2010-10-19

    Compositions, systems and methods are described for condensed phase conversion and growth of nanorods and other materials. A method includes providing a condensed phase matrix material; and activating the condensed phase matrix material to produce a plurality of nanorods by condensed phase conversion and growth from the condensed phase matrix material instead of from vapor. The compositions are very strong. The compositions and methods provide advantages because they allow (1) formation rates of nanostructures necessary for reasonable production rates, and (2) the near net shaped production of component structures.

  17. Reducing dislocations in semiconductors utilizing repeated thermal cycling during multistage epitaxial growth

    DOE Patents [OSTI]

    Fan, John C. C. (Chestnut Hill, MA); Tsaur, Bor-Yeu (Arlington, MA); Gale, Ronald P. (Bedford, MA); Davis, Frances M. (Framingham, MA)

    1992-02-25

    Dislocation densities are reduced in growing semiconductors from the vapor phase by employing a technique of interrupting growth, cooling the layer so far deposited, and then repeating the process until a high quality active top layer is achieved. The method of interrupted growth, coupled with thermal cycling, permits dislocations to be trapped in the initial stages of epitaxial growth.

  18. Reducing dislocations in semiconductors utilizing repeated thermal cycling during multistage epitaxial growth

    DOE Patents [OSTI]

    Fan, John C. C. (Chestnut Hill, MA); Tsaur, Bor-Yeu (Arlington, MA); Gale, Ronald P. (Bedford, MA); Davis, Frances M. (Framingham, MA)

    1986-12-30

    Dislocation densities are reduced in growing semiconductors from the vapor phase by employing a technique of interrupting growth, cooling the layer so far deposited, and then repeating the process until a high quality active top layer is achieved. The method of interrupted growth, coupled with thermal cycling, permits dislocations to be trapped in the initial stages of epitaxial growth.

  19. Metal organic chemical vapor deposition of 111-v compounds on silicon

    DOE Patents [OSTI]

    Vernon, Stanley M. (Wellesley, MA)

    1986-01-01

    Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.

  20. Phase-separated, epitaxial composite cap layers for electronic device applications and method of making the same

    DOE Patents [OSTI]

    Aytug, Tolga (Knoxville, TN); Paranthaman, Mariappan Parans (Knoxville, TN); Polat, Ozgur (Knoxville, TN)

    2012-07-17

    An electronic component that includes a substrate and a phase-separated layer supported on the substrate and a method of forming the same are disclosed. The phase-separated layer includes a first phase comprising lanthanum manganate (LMO) and a second phase selected from a metal oxide (MO), metal nitride (MN), a metal (Me), and combinations thereof. The phase-separated material can be an epitaxial layer and an upper surface of the phase-separated layer can include interfaces between the first phase and the second phase. The phase-separated layer can be supported on a buffer layer comprising a composition selected from the group consisting of IBAD MgO, LMO/IBAD-MgO, homoepi-IBAD MgO and LMO/homoepi-MgO. The electronic component can also include an electronically active layer supported on the phase-separated layer. The electronically active layer can be a superconducting material, a ferroelectric material, a multiferroic material, a magnetic material, a photovoltaic material, an electrical storage material, and a semiconductor material.

  1. Liquid-phase and vapor-phase dehydration of organic/water solutions

    DOE Patents [OSTI]

    Huang, Yu (Palo Alto, CA); Ly, Jennifer (San Jose, CA); Aldajani, Tiem (San Jose, CA); Baker, Richard W. (Palo Alto, CA)

    2011-08-23

    Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

  2. Compound nuclear decay and the liquid to vapor phase transition: a physical picture

    E-Print Network [OSTI]

    Moretto, L G; Phair, L

    2005-01-01

    Analyses of multifragmentation in terms of the Fisher droplet model (FDM) and the associated construction of a nuclear phase diagram bring forth the problem of the actual existence of the nuclear vapor phase and the meaning of its associated pressure. We present here a physical picture of fragment production from excited nuclei that solves this problem and establishes the relationship between the FDM and the standard compound nucleus decay rate for rare particles emitted in first-chance decay. The compound thermal emission picture is formally equivalent to a FDM-like equilibrium description and avoids the problem of the vapor while also explaining the observation of Boltzmann-like distribution of emission times. In this picture a simple Fermi gas thermometric relation is naturally justified and verified in the fragment yields and time scales. Low energy compound nucleus fragment yields scale according to the FDM and lead to an estimate of the infinite symmetric nuclear matter critical temperature between 18 a...

  3. Liquid-vapor phase transition in nuclei or compound nucleus decay?

    E-Print Network [OSTI]

    L. G. Moretto; J. B. Elliott; L. Phair; G. J. Wozniak

    2002-09-12

    Recent analyses of multifragmentation in terms of Fisher's model and the related construction of a phase diagram brings forth the problem of the true existence of the vapor phase and the meaning of its associated pressure. Our analysis shows that a thermal emission picture is equivalent to a Fisher-like equilibrium description which avoids the problem of the vapor and explains the recently observed Boltzmann-like distribution of the emission times. In this picture a simple Fermi gas thermometric relation is naturally justified. Low energy compound nucleus emission of intermediate mass fragments is shown to scale according to Fisher's formula and can be simultaneously fit with the much higher energy ISiS multifragmentation data.

  4. Tribology Letters Vol. 10, No. 3, 2001 179 Activation of the SiC surface for vapor phase lubrication

    E-Print Network [OSTI]

    Gellman, Andrew J.

    Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA E-mail: ag4b(ad), which then decompose by -hydride elimination resulting in H2, CO, H2CO, and CH3OH desorption phase lubrication in high temperature engines. KEY WORDS: lubrication; vapor phase lubrication; SiC; Fe

  5. Compound nuclear decay and the liquid to vapor phase transition: a physical picture

    E-Print Network [OSTI]

    L. G. Moretto; J. B. Elliott; L. Phair

    2005-07-08

    Analyses of multifragmentation in terms of the Fisher droplet model (FDM) and the associated construction of a nuclear phase diagram bring forth the problem of the actual existence of the nuclear vapor phase and the meaning of its associated pressure. We present here a physical picture of fragment production from excited nuclei that solves this problem and establishes the relationship between the FDM and the standard compound nucleus decay rate for rare particles emitted in first-chance decay. The compound thermal emission picture is formally equivalent to a FDM-like equilibrium description and avoids the problem of the vapor while also explaining the observation of Boltzmann-like distribution of emission times. In this picture a simple Fermi gas thermometric relation is naturally justified and verified in the fragment yields and time scales. Low energy compound nucleus fragment yields scale according to the FDM and lead to an estimate of the infinite symmetric nuclear matter critical temperature between 18 and 27 MeV depending on the choice of the surface energy coefficient of nuclear matter.

  6. On the existence of vapor-liquid phase transition in dusty plasmas

    SciTech Connect (OSTI)

    Kundu, M.; Sen, A.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India); Avinash, K. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2014-10-15

    The phenomenon of phase transition in a dusty-plasma system (DPS) has attracted some attention in the past. Earlier Farouki and Hamaguchi [J. Chem. Phys. 101, 9876 (1994)] have demonstrated the existence of a liquid to solid transition in DPS where the dust particles interact through a Yukawa potential. However, the question of the existence of a vapor-liquid (VL) transition in such a system remains unanswered and relatively unexplored so far. We have investigated this problem by performing extensive molecular dynamics simulations which show that the VL transition does not have a critical curve in the pressure versus volume diagram for a large range of the Yukawa screening parameter ? and the Coulomb coupling parameter ?. Thus, the VL phase transition is found to be super-critical, meaning that this transition is continuous in the dusty plasma model given by Farouki and Hamaguchi. We provide an approximate analytic explanation of this finding by means of a simple model calculation.

  7. Fluid Phase Equilibria 243 (2006) 198205 Comment on "prediction of vapor pressures of solid organic

    E-Print Network [OSTI]

    Chickos, James S.

    2006-01-01

    of vapor pressures of solid organic compounds with a group contribution method" William E. Acree Jr gave satisfactory vapor pressure predictions for many organic compounds having vapor pressures well only for substituting into their predictive vapor pressure expression. The intent of this short

  8. A sharp interface method for compressible liquid-vapor flow with phase transition and surface tension

    E-Print Network [OSTI]

    Fechter, Stefan; Rohde, Christian; Zeiler, Christoph

    2015-01-01

    The numerical approximation of non-isothermal liquid-vapor flow within the compressible regime is a difficult task because complex physical effects at the phase interfaces can govern the global flow behavior. We present a sharp interface approach which treats the interface as a shock-wave like discontinuity. Any mixing of fluid phases is avoided by using the flow solver in the bulk regions only, and a ghost-fluid approach close to the interface. The coupling states for the numerical solution in the bulk regions are determined by the solution of local multi-phase Riemann problems across the interface. The Riemann solution accounts for the relevant physics by enforcing appropriate jump conditions at the phase boundary. A wide variety of interface effects can be handled in a thermodynamically consistent way. This includes surface tension or mass/energy transfer by phase transition. Moreover, the local normal speed of the interface, which is needed to calculate the time evolution of the interface, is given by the...

  9. Method for rapid, controllable growth and thickness, of epitaxial silicon films

    DOE Patents [OSTI]

    Wang, Qi (Littleton, CO); Stradins, Paul (Golden, CO); Teplin, Charles (Boulder, CO); Branz, Howard M. (Boulder, CO)

    2009-10-13

    A method of producing epitaxial silicon films on a c-Si wafer substrate using hot wire chemical vapor deposition by controlling the rate of silicon deposition in a temperature range that spans the transition from a monohydride to a hydrogen free silicon surface in a vacuum, to obtain phase-pure epitaxial silicon film of increased thickness is disclosed. The method includes placing a c-Si substrate in a HWCVD reactor chamber. The method also includes supplying a gas containing silicon at a sufficient rate into the reaction chamber to interact with the substrate to deposit a layer containing silicon thereon at a predefined growth rate to obtain phase-pure epitaxial silicon film of increased thickness.

  10. The Effect Of ZnO Addition On Co/C Catalyst For Vapor And Aqueous Phase Reforming Of Ethanol

    SciTech Connect (OSTI)

    Davidson, Stephen; Sun, Junming; Hong, Yongchun; Karim, Ayman M.; Datye, Abhaya K.; Wang, Yong

    2014-02-05

    The effect of ZnO addition on the oxidation behavior of Co along with catalytic performance in vapor and aqueous phase reforming of ethanol were investigated on Co supported on carbon black (XC-72R). Carbon was selected to minimize the support interactions. Effect of ZnO addition during both vapor and aqueous phase reforming were compared at 250 °C. ZnO addition inhibited the reduction of cobalt oxides by H2 and created surface sites for H2O activation. During vapor phase reforming at 450 °C the redox of cobalt, driven by steam oxidation and H2 reduction, trended to an equilibrium of Co0/Co2+. ZnO showed no significant effect on cobalt oxidation, inferred from the minor changes of C1 product yield. Surface sites created by ZnO addition enhanced water activation and oxidation of surface carbon species, increasing CO2 selectivity. At 250 °C cobalt reduction was minimal, in situ XANES demonstrated that ZnO addition significantly facilitated oxidation of Co0 under vapor phase reforming conditions, demonstrated by lower C1 product yield. Sites introduced by ZnO addition improved the COx selectivity at 250 °C. Both Co/C and Co-ZnO/C rapidly oxidized under aqueous phase reaction conditions at 250 °C, showing negligible activity in aqueous phase reforming. This work suggests that ZnO affects the activation of H2O for Co catalysts in ethanol reforming.

  11. Epitaxial {tau} phase MnAl thin films on MgO (001) with thickness-dependent magnetic anisotropy

    SciTech Connect (OSTI)

    Cui Yishen; Chen Wei [Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Yin Wenjing; Lu Jiwei [Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Wolf, Stuart A. [Department of Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2011-11-15

    In this study, ferromagnetic MnAl films were prepared by alternating Al/Mn quasi-monolayer deposition using a novel biased target ion beam deposition (BTIBD) technique. XRD results showed that the magnetic {tau} phase was well formed in MnAl thin films ({approx}10 nm), which grew epitaxially on single crystal MgO (001) substrates. The optimized saturation magnetization was {approx}394 emu/cc. Furthermore, we observed a thickness-dependent uniaxial anisotropy in ferromagnetic MnAl films, which was attributed to the change of the tetragonal lattice distortion as a function of film thickness. The relationship between the film thicknesses and saturation magnetizations suggested the existence of a magnetically dead layer {approx}2.7 nm with an extrapolated saturation moment around 523 emu/cc ({approx}1.90 {mu}{sub B}/Mn). This value has exceeded the experimental value in bulk materials and is close to the theoretically predicted magnetization ({approx}1.975 {mu}{sub B}/Mn).

  12. Comparative study of polar and semipolar (112?2) InGaN layers grown by metalorganic vapour phase epitaxy

    SciTech Connect (OSTI)

    Dinh, Duc V. E-mail: peter.parbrook@tyndall.ie; Zubialevich, V. Z.; Oehler, F.; Kappers, M. J.; Humphreys, C. J.; Alam, S. N.; Parbrook, P. J. E-mail: peter.parbrook@tyndall.ie; Caliebe, M.; Scholtz, F.

    2014-10-21

    InGaN layers were grown simultaneously on (112?2) GaN and (0001) GaN templates by metalorganic vapour phase epitaxy. At higher growth temperature (?750°C), the indium content (<15%) of the (112?2) and (0001) InGaN layers was similar. However, for temperatures less than 750°C, the indium content of the (112?2) InGaN layers (15%–26%) were generally lower than those with (0001) orientation (15%–32%). The compositional deviation was attributed to the different strain relaxations between the (112?2) and (0001) InGaN layers. Room temperature photoluminescence measurements of the (112?2) InGaN layers showed an emission wavelength that shifts gradually from 380 nm to 580 nm with decreasing growth temperature (or increasing indium composition). The peak emission wavelength of the (112?2) InGaN layers with an indium content of more than 10% blue-shifted a constant value of ?(50–60) nm when using higher excitation power densities. This blue-shift was attributed to band filling effects in the layers.

  13. Nanoscale Phase Separation In Epitaxial Cr-Mo and Cr-V Alloy Thin Films Studied Using Atom Probe Tomography: Comparison Of Experiments And Simulation

    SciTech Connect (OSTI)

    Devaraj, Arun; Kaspar, Tiffany C.; Ramanan, Sathvik; Walvekar, Sarita K.; Bowden, Mark E.; Shutthanandan, V.; Kurtz, Richard J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxial (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation it is very challenging to characterize by conventional techniques. Therefor laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr0.61Mo0.39, Cr0.77Mo0.23, and Cr0.32V0.68 alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were thus confirmed.

  14. Nanoscale phase separation in epitaxial Cr-Mo and Cr-V alloy thin films studied using atom probe tomography: Comparison of experiments and simulation

    SciTech Connect (OSTI)

    Devaraj, A.; Ramanan, S.; Walvekar, S.; Bowden, M. E.; Shutthanandan, V.; Kaspar, T. C.; Kurtz, R. J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxy (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However, the presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation, it is very challenging to characterize by conventional techniques. Therefore, laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr{sub 0.61}Mo{sub 0.39}, Cr{sub 0.77}Mo{sub 0.23}, and Cr{sub 0.32}V{sub 0.68} alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus, the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were confirmed.

  15. The Hall mobility measurement of Liquid Phase Epitaxy grown aluminum gallium arsenide 

    E-Print Network [OSTI]

    Choi, Young-Shig

    1986-01-01

    ' Committee) 8~zP~ Donald L. Parker (Member) . / ! "Yp Thomas W. Adair 111 (Member) Ran al L. Geif;er ( i vl e &n h p. I' ) . ). W. Howze (II& ad of' D& partrnenf. ) D&'c&" rnb& r f!)f&(i ABSTRACT The Hall Mobility Measurement ol' Liquid Phase... keep unwanted irnpurit, ies in solut. ion. They & a. n also be made very thin, i. e. . a, few microns. 'I'hese factors make LPE important &o the bet&&rostructur& devi& e for the growth ol' non-silicon based materials, which ar& used to fabricat& a...

  16. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    SciTech Connect (OSTI)

    Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

    2013-10-01

    Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

  17. Journal of Crystal Growth 281 (2005) 209219 Effect of a CuSe secondary phase on the epitaxial

    E-Print Network [OSTI]

    Anderson, Timothy J.

    2005-01-01

    -cost thin-film solar cells. The advantages of this class of materials include their high that appears during epitaxial growth of CuInSe2 (CIS) films on (1 0 0) GaAs substrates was investigated. CIS films with different copper to indium molar ratios were deposited on (1 0 0) GaAs substrates at 360 1C

  18. Desalination-of water by vapor-phase transport through hydrophobic nanopores

    E-Print Network [OSTI]

    Lee, Jongho

    We propose a new approach to desalination of water whereby a pressure difference across a vapor-trapping nanopore induces selective transport of water by isothermal evaporation and condensation across the pore. Transport ...

  19. The role of polymer formation during vapor phase lubrication of silicon.

    SciTech Connect (OSTI)

    Dugger, Michael Thomas; Dirk, Shawn M.; Ohlhausen, James Anthony

    2010-10-01

    The lubrication of silicon surfaces with alcohol vapors has recently been demonstrated. With a sufficient concentration of pentanol vapor present, sliding of a silica ball on an oxidized silicon wafer can proceed with no measurable wear. The initial results of time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of wear surfaces revealed a reaction product having thickness on the order of a monolayer, and with an ion spectrum that included fragments having molecular weights of 200 or more that occurred only inside the wear tracks. The parent alcohol molecule pentanol, has molecular weight of 88amu, suggesting that reactions of adsorbed alcohols on the wearing surfaces allowed polymerization of the alcohols to form higher molecular weight species. In addition to pin-on-disk studies, lubrication of silicon surfaces with pentanol vapors has also been demonstrated using MicroElectroMechanical Systems (MEMS) devices. Recent investigations of the reaction mechanisms of the alcohol molecules with the oxidized silicon surfaces have shown that wearless sliding requires a concentration of the alcohol vapor that is dependent upon the contact stress during sliding, with higher stress requiring a greater concentration of alcohol. Different vapor precursors including those with acid functionality, olefins, and methyl termination also produce polymeric reaction products, and can lubricate the silica surfaces. Doping the operating environment with oxygen was found to quench the formation of the polymeric reaction product, and demonstrates that polymer formation is not necessary for wearless sliding.

  20. Treatment of Produced Waters Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    SciTech Connect (OSTI)

    Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Lynn E. Katz; Kerry A. Kinney; R. S. Bowman; E. J. Sullivan

    2005-03-11

    This report summarizes work performed on this project from October 2004 through March 2005. In previous work, a surfactant modified zeolite (SMZ) was shown to be an effective system for removing BTEX contaminants from produced water. Additional work on this project demonstrated that a compost-based biofilter could biodegrade the BTEX contaminants found in the SMZ regeneration waste gas stream. However, it was also determined that the BTEX concentrations in the waste gas stream varied significantly during the regeneration period and the initial BTEX concentrations were too high for the biofilter to handle effectively. A series of experiments were conducted to determine the feasibility of using a passive adsorption column placed upstream of the biofilter to attenuate the peak gas-phase VOC concentrations delivered to the biofilter during the SMZ regeneration process. In preparation for the field test of the SMZ/VPB treatment system in New Mexico, a pilot-scale SMZ system was also designed and constructed during this reporting period. Finally, a cost and feasibility analysis was also completed. To investigate the merits of the passive buffering system during SMZ regeneration, two adsorbents, SMZ and granular activated carbon (GAC) were investigated in flow-through laboratory-scale columns to determine their capacity to handle steady and unsteady VOC feed conditions. When subjected to a toluene-contaminated air stream, the column containing SMZ reduced the peak inlet 1000 ppmv toluene concentration to 630 ppmv at a 10 second contact time. This level of buffering was insufficient to ensure complete removal in the downstream biofilter and the contact time was longer than desired. For this reason, using SMZ as a passive buffering system for the gas phase contaminants was not pursued further. In contrast to the SMZ results, GAC was found to be an effective adsorbent to handle the peak contaminant concentrations that occur early during the SMZ regeneration process. At a one second residence time, the GAC bed reduced peak contaminant concentrations by 97%. After the initial peak, the inlet VOC concentration in the SMZ regeneration gas stream drops exponentially with time. During this period, the contaminants on the GAC subsequently desorbed at a nearly steady rate over the next 45 hours resulting in a relatively steady effluent concentration of approximately 25 ppm{sub v}. This lower concentration is readily degradable by a downstream vapor phase biofilter (VPB) and the steady nature of the feed stream will prevent the biomass in the VPB from enduring starvation conditions between SMZ regeneration cycles. Repetitive sorption and desorption cycles that would be expected in the field were also investigated. It was determined that although the GAC initially lost some VOC sorption capacity, the adsorption and desorption profiles stabilized after approximately 6 cycles indicating that a GAC bed should be suitable for continuous operation. In preparation for the pilot field testing of the SMZ/VPB system, design, ''in-house'' construction and testing of the field system were completed during this project period. The design of the SMZ system for the pilot test was based on previous investigations by the PI's in Wyoming, 2002 and on analyses of the produced water at the field site in New Mexico. The field tests are scheduled for summer, 2005. A cost survey, feasibility of application and cost analyses were completed to investigate the long term effectiveness of the SMZ/VPB system as a method of treating produced water for re-use. Several factors were investigated, including: current costs to treat and dispose of produced water, end-use water quality requirements, and state and federal permitting requirements.

  1. Treatment of Produced Water Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    SciTech Connect (OSTI)

    Lynn E. Katz; Kerry A. Kinney; Robert S. Bowman; Enid J. Sullivan; Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Craig R. Altare

    2006-01-31

    Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. Produced waters typically contain a high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component as well as chemicals added during the oil-production process. It has been estimated that a total of 14 billion barrels of produced water were generated in 2002 from onshore operations (Veil, 2004). Although much of this produced water is disposed via reinjection, environmental and cost considerations can make surface discharge of this water a more practical means of disposal. In addition, reinjection is not always a feasible option because of geographic, economic, or regulatory considerations. In these situations, it may be desirable, and often necessary from a regulatory viewpoint, to treat produced water before discharge. It may also be feasible to treat waters that slightly exceed regulatory limits for re-use in arid or drought-prone areas, rather than losing them to reinjection. A previous project conducted under DOE Contract DE-AC26-99BC15221 demonstrated that surfactant modified zeolite (SMZ) represents a potential treatment technology for produced water containing BTEX. Laboratory and field experiments suggest that: (1) sorption of benzene, toluene, ethylbenzene and xylenes (BTEX) to SMZ follows linear isotherms in which sorption increases with increasing solute hydrophobicity; (2) the presence of high salt concentrations substantially increases the capacity of the SMZ for BTEX; (3) competitive sorption among the BTEX compounds is negligible; and, (4) complete recovery of the SMZ sorption capacity for BTEX can be achieved by air sparging the SMZ. This report summarizes research for a follow on project to optimize the regeneration process for multiple sorption/regeneration cycles, and to develop and incorporate a vapor phase bioreactor (VPB) system for treatment of the off-gas generated during air sparging. To this end, we conducted batch and column laboratory SMZ and VPB experiments with synthetic and actual produced waters. Based on the results of the laboratory testing, a pilot scale study was designed and conducted to evaluate the combined SMZ/VPB process. An economic and regulatory feasibility analysis was also completed as part of the current study to assess the viability of the process for various water re-use options.

  2. TREATMENT OF PRODUCED WATERS USING A SURFACTANT MODIFIED ZEOLITE/VAPOR PHASE BIOREATOR SYSTEM

    SciTech Connect (OSTI)

    LYNN E. KATZ; KERRY A. KINNEY; R.S. BOWMAN; E.J. SULLIVAN

    2003-10-01

    Co-produced water from the oil and gas industry is by some estimates the largest single waste stream in the country, aside from nonhazardous industrial wastes. Characteristics of produced water include high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component, and chemicals added during the oil-production process. While most of the produced water is disposed via reinjection, some of them must be treated to remove organic constituents before the water is discharged. An efficient, cost-effective treatment technology is needed to remove these constituents. Surfactant-modified zeolite (SMZ) has been used successfully to treat contaminated ground water for organic and inorganic constituents. In addition, the low cost of natural zeolites makes their use attractive in water-treatment applications. Our previous DOE research work (DE-AC26-99BC15221) demonstrated that SMZ could successfully remove BTEX compounds from the produced water. In addition, SMZ could be regenerated through a simple air sparging process. The primary goal of this project is to develop a robust SMZ/VPB treatment system to efficiently remove the organic constituents from produced water in a cost-effective manner. This report summarizes work of this project from March 2003 through September 2003. We have continued our investigation of SMZ regeneration from our previous DOE project. Ten saturation/stripping cycles have been completed for SMZ columns saturated with BTEX compounds. The results suggest that BTEX sorption capacity is not lost after ten saturation/regeneration cycles. The composition of produced water from a site operated by Crystal Solutions Ltd. in Wyoming has been characterized and was used to identify key semi-volatile components. Isotherms with selected semi-volatile components have been initiated and preliminary results have been obtained. The experimental vapor phase bioreactors for this project have been designed and assembled to treat the off-gas from the SMZ regeneration process. These columns will be used both in the laboratory and in the proposed field testing to be conducted next year. Innocula for the columns that degrade all of the BTEX columns have been developed.

  3. Phase transition and ferroelectric properties of epitaxially strained KNbO3/NaNbO3 superlattice

    E-Print Network [OSTI]

    Cao, Wenwu

    , because lead oxide vaporizes during the fabrica- tion process, which is harmful to the environment: 10.1063/1.3053148 Lead based piezoelectric ceramic Pb Zr1-xTix O3 PZT has been widely used, the devel- opment of lead-free ferroelectric materials with properties comparable to lead based compounds

  4. A low phase noise microwave frequency synthesis for a high-performance cesium vapor cell atomic clock

    SciTech Connect (OSTI)

    François, B.; Boudot, R.; Calosso, C. E.; Danet, J. M.

    2014-09-15

    We report the development, absolute phase noise, and residual phase noise characterization of a 9.192?GHz microwave frequency synthesis chain devoted to be used as a local oscillator in a high-performance cesium vapor cell atomic clock based on coherent population trapping (CPT). It is based on frequency multiplication of an ultra-low phase noise 100 MHz oven-controlled quartz crystal oscillator using a nonlinear transmission line-based chain. Absolute phase noise performances of the 9.192?GHz output signal are measured to be ?42, ?100, ?117 dB?rad{sup 2}/Hz and ?129 dB?rad{sup 2}/Hz at 1 Hz, 100 Hz, 1 kHz, and 10 kHz offset frequencies, respectively. Compared to current results obtained in a state-of-the-art CPT-based frequency standard developed at LNE-SYRTE, this represents an improvement of 8 dB and 10 dB at f = 166 Hz and f = 10 kHz, respectively. With such performances, the expected Dick effect contribution to the atomic clock short term frequency stability is reported at a level of 6.2 × 10{sup ?14} at 1 s integration time, that is a factor 3 higher than the atomic clock shot noise limit. Main limitations are pointed out.

  5. Comment on "Tunable generation and adsorption of energetic compounds in the vapor phase at trace levels: A tool for testing and developing sensitive and selective substrates for explosive detection"

    SciTech Connect (OSTI)

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2013-02-13

    The evaluation of developed technologies and research on new detection approaches require the ability to generate explosive vapors in the gas phase. In this correspondence, the authors comment on a technical note describing a vaopr generator, discuss safety issues associated with explosives for vapor generators, and provide a concise review of vapor generators for explosive compounds. Approaches to measuring or monitoring the output of a vapor generators are also discussed.

  6. ICES REPORT 15-14 Liquid-Vapor Phase Transition: Thermomechanical

    E-Print Network [OSTI]

    ICES

    -order time-accurate. Isogeometric analysis is utilized for spatial discretization. The analytical properties, Phase transition, Evaporation, Condensation, Boiling 1 #12;1 Introduction 1.1 Phase transition induced by temperature variations can be observed in daily life as boiling, evaporation, and condensation

  7. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    DOE Patents [OSTI]

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  8. Relaxation and critical strain for maximum In incorporation in AlInGaN on GaN grown by metal organic vapour phase epitaxy

    SciTech Connect (OSTI)

    Reuters, Benjamin; Finken, M.; Wille, A.; Kalisch, H.; Vescan, A.; Hollaender, B.; Heuken, M.

    2012-11-01

    Quaternary AlInGaN layers were grown on conventional GaN buffer layers on sapphire by metal organic vapour phase epitaxy at different surface temperatures and different reactor pressures with constant precursor flow conditions. A wide range in compositions within 30-62% Al, 5-29% In, and 23-53% Ga was covered, which leads to different strain states from high tensile to high compressive. From high-resolution x-ray diffraction and Rutherford backscattering spectrometry, we determined the compositions, strain states, and crystal quality of the AlInGaN layers. Atomic force microscopy measurements were performed to characterize the surface morphology. A critical strain value for maximum In incorporation near the AlInGaN/GaN interface is presented. For compressively strained layers, In incorporation is limited at the interface as residual strain cannot exceed an empirical critical value of about 1.1%. Relaxation occurs at about 15 nm thickness accompanied by strong In pulling. Tensile strained layers can be grown pseudomorphically up to 70 nm at a strain state of 0.96%. A model for relaxation in compressively strained AlInGaN with virtual discrete sub-layers, which illustrates the gradually changing lattice constant during stress reduction is presented.

  9. Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures of Polyaromatic Heterocycles and Related Compounds

    E-Print Network [OSTI]

    Chickos, James S.

    Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures The vaporization enthalpies and vapor pressures of the liqiud phase from T ) 298.15 K to T ) 500 K of a series in the literature was measured on a hydrated form. Vapor pressures and normal boiling temperatures for the liquid

  10. Microstructure-electromechanical property correlations in rare-earth-substituted BiFeO3 epitaxial thin films at morphotropic phase boundaries

    E-Print Network [OSTI]

    Rubloff, Gary W.

    Microstructure-electromechanical property correlations in rare-earth- substituted BiFeO3 epitaxial November 2010; published online 24 November 2010 Structure-electromechanical property correlations in rare to the formation of the boundary.5 While the origin of the enhanced electromechanical re- sponse was theoretically

  11. 1066 IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 15, NO. 4, JULY/AUGUST 2009 Metalorganic Vapor Phase Epitaxy of III-Nitride

    E-Print Network [OSTI]

    Gilchrist, James F.

    substrate exhibited a 24% improvement in output power as compared to LEDs on GaN templates grown using the conventional method. The increase in output power of the LEDs is attributed to improved internal quantum-emitting diode (LED) de- vices grown on patterned sapphire and planar substrates were compared. The nanopatterned

  12. InAs quantum dot growth on Al{sub x}Ga{sub 1?x}As by metalorganic vapor phase epitaxy for intermediate band solar cells

    SciTech Connect (OSTI)

    Jakomin, R.; Kawabata, R. M. S.; Souza, P. L.; Mourão, R. T.; Pires, M. P.; Micha, D. N.

    2014-09-07

    InAs quantum dot multilayers have been grown using Al{sub x}Ga{sub 1?x}As spacers with dimensions and compositions near the theoretical values for optimized efficiencies in intermediate band photovoltaic cells. Using an aluminium composition of x?=?0.3 and InAs dot vertical dimensions of 5?nm, transitions to an intermediate band with energy close to the ideal theoretical value have been obtained. Optimum size uniformity and density have been achieved by capping the quantum dots with GaAs following the indium-flush method. This approach has also resulted in minimization of crystalline defects in the epilayer structure.

  13. Improved photoluminescence of InGaAsN,,In...GaAsP quantum well by organometallic vapor phase epitaxy using growth pause annealing

    E-Print Network [OSTI]

    Gilchrist, James F.

    for Photonics, Department of Electrical Computer Engineering, University of Wisconsin­Madison, 1415 Engineering are the hydride sources of AsH3 and PH3 . The trimethyl precursors of gal- lium Ga , aluminum Al , and indium

  14. Numerical simulations of epitaxial growth process in MOVPE reactor as a tool for design of modern semiconductors for high power electronics

    SciTech Connect (OSTI)

    Skibinski, Jakub; Wejrzanowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Woloska 141, 02507 Warsaw (Poland); Caban, Piotr [Institute of Electronic Materials Technology, Wolczynska 133, 01919 Warsaw (Poland); Kurzydlowski, Krzysztof J. [Warsaw University of Technology, Faculty of Materials Science and Engineering Woloska, 141, 02507 Warsaw (Poland)

    2014-10-06

    In the present study numerical simulations of epitaxial growth of gallium nitride in Metal Organic Vapor Phase Epitaxy reactor AIX-200/4RF-S is addressed. Epitaxial growth means crystal growth that progresses while inheriting the laminar structure and the orientation of substrate crystals. One of the technological problems is to obtain homogeneous growth rate over the main deposit area. Since there are many agents influencing reaction on crystal area such as temperature, pressure, gas flow or reactor geometry, it is difficult to design optimal process. According to the fact that it's impossible to determine experimentally the exact distribution of heat and mass transfer inside the reactor during crystal growth, modeling is the only solution to understand the process precisely. Numerical simulations allow to understand the epitaxial process by calculation of heat and mass transfer distribution during growth of gallium nitride. Including chemical reactions in numerical model allows to calculate the growth rate of the substrate and estimate the optimal process conditions for obtaining the most homogeneous product.

  15. Cantilever epitaxial process

    DOE Patents [OSTI]

    Ashby, Carol I.; Follstaedt, David M.; Mitchell, Christine C.; Han, Jung

    2003-07-29

    A process of growing a material on a substrate, particularly growing a Group II-VI or Group III-V material, by a vapor-phase growth technique where the growth process eliminates the need for utilization of a mask or removal of the substrate from the reactor at any time during the processing. A nucleation layer is first grown upon which a middle layer is grown to provide surfaces for subsequent lateral cantilever growth. The lateral growth rate is controlled by altering the reactor temperature, pressure, reactant concentrations or reactant flow rates. Semiconductor materials, such as GaN, can be produced with dislocation densities less than 10.sup.7 /cm.sup.2.

  16. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Demaurex, Bénédicte; Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Alexander, Duncan T. L.; Jeangros, Quentin; Ballif, Christophe; De Wolf, Stefaan

    2014-08-05

    Low-temperature (? 180 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-ehanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems notmore »only from the growth conditions but also from unintentional contamination of the reactor. As a result of our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.« less

  17. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    SciTech Connect (OSTI)

    Demaurex, Bénédicte, E-mail: benedicte.demaurex@epfl.ch; Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Ballif, Christophe; De Wolf, Stefaan [École Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory, Maladière 71B, CH-2000 Neuchâtel (Switzerland); Alexander, Duncan T. L.; Jeangros, Quentin [École Polytechnique Fédérale de Lausanne (EPFL), Interdisciplinary Centre for Electron Microscopy (CIME), Station 12, CH-1015 Lausanne (Switzerland)

    2014-08-07

    Low-temperature (?200?°C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-enhanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems not only from the growth conditions but also from unintentional contamination of the reactor. Based on our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.

  18. Low-temperature plasma-deposited silicon epitaxial films: Growth and properties

    SciTech Connect (OSTI)

    Demaurex, Bénédicte; Bartlome, Richard; Seif, Johannes P.; Geissbühler, Jonas; Alexander, Duncan T. L.; Jeangros, Quentin; Ballif, Christophe; De Wolf, Stefaan

    2014-08-07

    Low-temperature (? 180 °C) epitaxial growth yields precise thickness, doping, and thermal-budget control, which enables advanced-design semiconductor devices. In this paper, we use plasma-ehanced chemical vapor deposition to grow homo-epitaxial layers and study the different growth modes on crystalline silicon substrates. In particular, we determine the conditions leading to epitaxial growth in light of a model that depends only on the silane concentration in the plasma and the mean free path length of surface adatoms. For such growth, we show that the presence of a persistent defective interface layer between the crystalline silicon substrate and the epitaxial layer stems not only from the growth conditions but also from unintentional contamination of the reactor. Based on our findings, we determine the plasma conditions to grow high-quality bulk epitaxial films and propose a two-step growth process to obtain device-grade material.

  19. Vaporization of zinc from scrap

    SciTech Connect (OSTI)

    Ozturk, B.; Fruehan, R.J. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1996-12-31

    The rate of zinc vaporization from galvanized scrap was measured using a thermogravimetric apparatus along with chemical analysis. It is found that the rate of zinc vaporization is very fast in nitrogen and carbon monoxide atmospheres at temperatures higher than 950 C. At lower temperature rate decreases with decreasing temperature and is controlled by the gas phase mass transport. The simultaneous oxidation and vaporization of zinc occurs when the samples were heated in carbon dioxide and air. The current experimental results indicate that almost all of the zinc from scrap vaporizes during the heating process in a very short period of time after the temperature reaches above 850 C.

  20. Epitaxial thin film growth of LiH using a liquid-Li atomic template

    SciTech Connect (OSTI)

    Oguchi, Hiroyuki; Ikeshoji, Tamio; Orimo, Shin-ichi; Ohsawa, Takeo; Shiraki, Susumu; Hitosugi, Taro; Kuwano, Hiroki

    2014-11-24

    We report on the synthesis of lithium hydride (LiH) epitaxial thin films through the hydrogenation of a Li melt, forming abrupt LiH/MgO interface. Experimental and first-principles molecular dynamics studies reveal a comprehensive microscopic picture of the crystallization processes, which sheds light on the fundamental atomistic growth processes that have remained unknown in the vapor-liquid-solid method. We found that the periodic structure that formed, because of the liquid-Li atoms at the film/MgO-substrate interface, serves as an atomic template for the epitaxial growth of LiH crystals. In contrast, films grown on the Al{sub 2}O{sub 3} substrates indicated polycrystalline films with a LiAlO{sub 2} secondary phase. These results and the proposed growth process provide insights into the preparation of other alkaline metal hydride thin films on oxides. Further, our investigations open the way to explore fundamental physics and chemistry of metal hydrides including possible phenomena that emerge at the heterointerfaces of metal hydrides.

  1. Liquid-phase compositions from vapor-phase analyses: 4, Preliminary comparisons of calculations with experimental data on N/sub 2/, O/sub 2/, F/sub 2/, SiF/sub 4/, and ClF/sub 3/ in UF/sub 6/

    SciTech Connect (OSTI)

    Davis, W. Jr.

    1987-11-01

    Currently, liquid-phase samples from uranium hexafluoride (UF/sub 6/) cylinders are used at all US DOE /sup 235/U enrichment facilities to determine the chemical content of cylinders - a requisite in the control and accountability of nuclear materials. Previously published reports note the economic incentives to use vapor-phase sampling for volatile impurities (as a partial replacement for liquid-phase sampling) if the liquid-phase composition can be determined from analysis of vapor-phase samples by using a model of vapor-liquid equilibrium between UF/sub 6/ and its common impurities. Such a model was adapted for this purpose in earlier work. Hydrogen fluoride, a common impurity, in UF/sub 6/ was shown not to conform to the model although other methods for calculating its concentration in the liquid phase from vapor-phase analyses were presented. This report describes preliminary comparisons with experimental data of model calculations of concentrations of nitrogen, oxygen, fluorine, chlorine trifluoride, and silicon tetrafluoride in liquid UF/sub 6/ based on analyses of the vapor phases. 4 figs., 13 tabs.

  2. Experimental and Modeling Study of the Flammability of Fuel Tank Headspace Vapors from Ethanol/Gasoline Fuels, Phase 2: Evaluations of Field Samples and Laboratory Blends

    SciTech Connect (OSTI)

    Gardiner, D. P.; Bardon, M. F.; LaViolette, M.

    2010-04-01

    Study to measure the flammability of gasoline/ethanol fuel vapors at low ambient temperatures and develop a mathematical model to predict temperatures at which flammable vapors were likely to form.

  3. Epitaxial thin films

    DOE Patents [OSTI]

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  4. Reductive Dehalogenation of Trichloroethene Vapors in an

    E-Print Network [OSTI]

    to treat trichloroethene (TCE) from waste gases generated by soil vapor extraction or dual-phase extraction and groundwater include soil vapor extraction (SVE) in combination with air sparging and dual-phase extraction methods such as incineration, catalytic oxidation, and adsorption onto activated carbon are currently

  5. Ultralong minority-carrier lifetime epitaxial GaAs by photon recycling

    SciTech Connect (OSTI)

    Ahrenkiel, R.K.; Dunlavy, D.J.; Keyes, B. (Solar Energy Research Institute, Golden, Colorado 80401 (US)); Vernon, S.M.; Dixon, T.M.; Tobin, S.P. (Spire Corporation, Bedford, Massachusetts 01730); Miller, K.L.; Hayes, R.E. (Department of Electrical and Computer Engineering, University of Colorado, Boulder, Colorado 80303)

    1989-09-11

    The minority-carrier lifetime has been measured by time-resolved photoluminescence in epitaxial films of GaAs grown by metalorganic chemical vapor deposition. The measured lifetimes in thicker devices are 4 to 6 times the theoretical or radiative lifetime. These long lifetimes are the result of photon recycling or self-generation of the self-absorbed radiation.

  6. Nanoparticle-Mediated Epitaxial Assembly of Colloidal Crystals on Patterned Substrates

    E-Print Network [OSTI]

    Braun, Paul

    #12;Nanoparticle-Mediated Epitaxial Assembly of Colloidal Crystals on Patterned Substrates Wonmok Form: February 4, 2004 We have studied the assembly of 3-D colloidal crystals from binary mixtures solution surrounding the colloidal crystal was gelled in situ by introducing ammonia vapor, which increased

  7. Structure and magnetism of epitaxial rare-earth-transition-metal films

    SciTech Connect (OSTI)

    Fullerton, E.E.; Sowers, C.H.; Pearson, J.P.; Bader, S.D.

    1996-10-01

    Growth of epitaxial transition-metal superlattices; has proven essential in elucidating the role of crystal orientation and structure on magnetic properties such as giant magnetoresistance, interlayer coupling, and magnetic surface anisotropies. Extending these studies to the growth of epitaxial rare earth-transition metal (RE-TM) films and superlattices promises to play an equally important role in exploring and optimizing the properties of hard magnets. For instance, Skomski and Coey predict that a giant energy product (120 MG Oe) is possible in multilayer structures consisting of aligned hard-magnet layers exchanged coupled with soft-phase layers with high magnetization. Epitaxy provides one route to synthesizing such exchange-hardened magnets on controlled length scales. Epitaxial growth also allows the magnetic properties to be tailored by controlling the crystal orientation and the anisotropies of the magnetic layers and holds the possibility of stabilizing metastable phases. This paper describes the epitaxy and magnetic properties for several alloys.

  8. Numerical modeling of water injection into vapor-dominated geothermal reservoirs

    E-Print Network [OSTI]

    Pruess, Karsten

    2008-01-01

    s equation, which expresses vapor pressure as a function ofT+ 273.15 ) ( is the vapor pressure lowering (VPL) factor.P sat is the saturated vapor pressure of bulk aqueous phase,

  9. Portable vapor diffusion coefficient meter

    DOE Patents [OSTI]

    Ho, Clifford K. (Albuquerque, NM)

    2007-06-12

    An apparatus for measuring the effective vapor diffusion coefficient of a test vapor diffusing through a sample of porous media contained within a test chamber. A chemical sensor measures the time-varying concentration of vapor that has diffused a known distance through the porous media. A data processor contained within the apparatus compares the measured sensor data with analytical predictions of the response curve based on the transient diffusion equation using Fick's Law, iterating on the choice of an effective vapor diffusion coefficient until the difference between the predicted and measured curves is minimized. Optionally, a purge fluid can forced through the porous media, permitting the apparatus to also measure a gas-phase permeability. The apparatus can be made lightweight, self-powered, and portable for use in the field.

  10. Long Term Field Development of a Surfactant Modified Zeolite/Vapor Phase Bioreactor System for Treatment of Produced Waters for Power Generation

    SciTech Connect (OSTI)

    Lynn Katz; Kerry Kinney; Robert Bowman; Enid Sullivan; Soondong Kwon; Elaine Darby; Li-Jung Chen; Craig Altare

    2007-12-31

    The main goal of this research was to investigate the feasibility of using a combined physicochemical/biological treatment system to remove the organic constituents present in saline produced water. In order to meet this objective, a physical/chemical adsorption process was developed and two separate biological treatment techniques were investigated. Two previous research projects focused on the development of the surfactant modified zeolite adsorption process (DE-AC26-99BC15221) and development of a vapor phase biofilter (VPB) to treat the regeneration off-gas from the surfactant modified zeolite (SMZ) adsorption system (DE-FC26-02NT15461). In this research, the SMZ/VPB was modified to more effectively attenuate peak loads and to maintain stable biodegradation of the BTEX constituents from the produced water. Specifically, a load equalization system was incorporated into the regeneration flow stream. In addition, a membrane bioreactor (MBR) system was tested for its ability to simultaneously remove the aromatic hydrocarbon and carboxylate components from produced water. The specific objectives related to these efforts included the following: (1) Optimize the performance VPBs treating the transient loading expected during SMZ regeneration: (a) Evaluate the impact of biofilter operating parameters on process performance under stable operating conditions. (b) Investigate how transient loads affect biofilter performance, and identify an appropriate technology to improve biological treatment performance during the transient regeneration period of an SMZ adsorption system. (c) Examine the merits of a load equalization technology to attenuate peak VOC loads prior to a VPB system. (d) Evaluate the capability of an SMZ/VPB to remove BTEX from produced water in a field trial. (2) Investigate the feasibility of MBR treatment of produced water: (a) Evaluate the biodegradation of carboxylates and BTEX constituents from synthetic produced water in a laboratory-scale MBR. (b) Evaluate the capability of an SMZ/MBR system to remove carboxylates and BTEX from produced water in a field trial. Laboratory experiments were conducted to provide a better understanding of each component of the SMZ/VPB and SMZ/MBR process. Laboratory VPB studies were designed to address the issue of influent variability and periodic operation (see DE-FC26-02NT15461). These experiments examined multiple influent loading cycles and variable concentration loadings that simulate air sparging as the regeneration option for the SMZ system. Two pilot studies were conducted at a produced water processing facility near Farmington, New Mexico. The first field test evaluated SMZ adsorption, SMZ regeneration, VPB buffering, and VPB performance, and the second test focused on MBR and SMZ/MBR operation. The design of the field studies were based on the results from the previous field tests and laboratory studies. Both of the biological treatment systems were capable of removing the BTEX constituents in the laboratory and in the field over a range of operating conditions. For the VPB, separation of the BTEX constituents from the saline aqueous phase yielded high removal efficiencies. However, carboxylates remained in the aqueous phase and were not removed in the combined VPB/SMZ system. In contrast, the MBR was capable of directly treating the saline produced water and simultaneously removing the BTEX and carboxylate constituents. The major limitation of the MBR system is the potential for membrane fouling, particularly when the system is treating produced water under field conditions. The combined process was able to effectively pretreat water for reverse osmosis treatment and subsequent downstream reuse options including utilization in power generation facilities. The specific conclusions that can be drawn from this study are summarized.

  11. Authorized Limit Evaluation of Spent Granular Activated Carbon Used for Vapor-Phase Remediation at the Lawrence Livermore National Laboratory Livermore, California

    SciTech Connect (OSTI)

    Devany, R; Utterback, T

    2007-01-11

    This report provides a technical basis for establishing radiological release limits for granular activated carbon (GAC) containing very low quantities of tritium and radon daughter products generated during environmental remediation activities at Lawrence Livermore National Laboratory (LLNL). This evaluation was conducted according to the Authorized Limit procedures specified in United States Department of Energy (DOE) Order 5400.5, Radiation Protection of the Public and the Environment (DOE, 1993) and related DOE guidance documents. The GAC waste is currently being managed by LLNL as a Resource Conservation and Recovery Act (RCRA) mixed waste. Significant cost savings can be achieved by developing an Authorized Limit under DOE Order 5400.5 since it would allow the waste to be safely disposed as a hazardous waste at a permitted off-site RCRA treatment and disposal facility. LLNL generates GAC waste during vapor-phase soil remediation in the Trailer 5475 area. While trichloroethylene and other volatile organic compounds (VOCs) are the primary targets of the remedial action, a limited amount of tritium and radon daughter products are contained in the GAC at the time of disposal. As defined in DOE Order 5400.5, an Authorized Limit is a level of residual radioactive material that will result in an annual public dose of 100 milliroentgen-equivalent man per year (mrem/year) or less. In 1995, DOE issued additional release requirements for material sent to a landfill that is not an authorized low-level radioactive waste disposal facility. Per guidance, the disposal site will be selected based on a risk/benefit assessment under the As-Low-As-Reasonably-Achievable (ALARA) process while ensuring that individual doses to the public are less than 25 mrem in a year, ground water is protected, the release would not necessitate further remedial action for the disposal site, and the release is coordinated with all appropriate authorities. The 1995 release requirements also state that Authorized Limits may be approved by DOE field office managers without DOE headquarters (EH-1) approval if a reasonably conservative dose assessment demonstrates that: (1) Public doses will not exceed one mrem per year individually or 10 person-rem/year collectively; (2) Appropriate record keeping and data collection procedures are in place; (3) Copies of the release evaluation and procedures are properly maintained; and (4) Coordination with all applicable state and federal agencies is documented. Based on the above guidelines, this report uses one mrem/year for individual members of the public and 10 person-rem/year for the collective population as upper-bound doses for the determination of Authorized Limits.

  12. Image Storage in Hot Vapors

    E-Print Network [OSTI]

    L. Zhao; T. Wang; Y. Xiao; S. F. Yelin

    2007-10-22

    We theoretically investigate image propagation and storage in hot atomic vapor. A $4f$ system is adopted for imaging and an atomic vapor cell is placed over the transform plane. The Fraunhofer diffraction pattern of an object in the object plane can thus be transformed into atomic Raman coherence according to the idea of ``light storage''. We investigate how the stored diffraction pattern evolves under diffusion. Our result indicates, under appropriate conditions, that an image can be reconstructed with high fidelity. The main reason for this procedure to work is the fact that diffusion of opposite-phase components of the diffraction pattern interfere destructively.

  13. The Controller Synthesis of Metastable Oxides Utilizing Epitaxy and Epitaxial Stabilization

    SciTech Connect (OSTI)

    Schlom, Darrell

    2003-12-02

    Molecular beam epitaxy (MBE) has achieved unparalleled control in the integration of semiconductors at the nanometer. These advances were made through the use of epitaxy, epitaxial stabilization, and a combination of composition-control techniques including adsorption-controlled growth and RHEED-based composition control that we have developed, understood, and utilized for the growth of oxides. Also key was extensive characterization (utilizing RHEED, four-circle x-ray diffraction, AFM, TEM, and electrical characterization techniques) in order to study growth modes, optimize growth conditions, and probe the structural, dielectric, and ferroelectric properties of the materials grown. The materials that we have successfully engineered include titanates (PbTiO3, Bi4Ti3O12), tantalates (SrBi2Ta2O9), and niobates (SrBi2Nb2O9); layered combinations of these perovskite-related materials (Bi4Ti3O12-SrTiO3 and Bi4Ti3O12-PbTiO3 Aurivillius phases and metastable PbTiO3/SrTiO3 and BaTiO3/SrTiO3 superlattices), and new metastable phases (Srn+1TinO3n+1 Ruddlesden-Popper phases). The films were grown by reactive MBE and pulsed laser deposition (PLD). Many of these materials are either new or have been synthesized with the highest perfection ever reported. The controlled synthesis of such layered oxide heterostructures offers great potential for tailoring the superconducting, ferroelectric, and dielectric properties of these materials. These properties are important for energy technologies.

  14. Calibrated vapor generator source

    DOE Patents [OSTI]

    Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.

    1995-09-26

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.

  15. Calibrated vapor generator source

    DOE Patents [OSTI]

    Davies, John P. (Idaho Falls, ID); Larson, Ronald A. (Idaho Falls, ID); Goodrich, Lorenzo D. (Shelley, ID); Hall, Harold J. (Idaho Falls, ID); Stoddard, Billy D. (Idaho Falls, ID); Davis, Sean G. (Idaho Falls, ID); Kaser, Timothy G. (Idaho Falls, ID); Conrad, Frank J. (Albuquerque, NM)

    1995-01-01

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

  16. Quality of epitaxial InAs nanowires controlled by catalyst size in molecular beam epitaxy

    SciTech Connect (OSTI)

    Zhang, Zhi; Xu, Hong-Yi; Guo, Ya-Nan; Liao, Zhi-Ming; Lu, Zhen-Yu; Chen, Ping-Ping; Shi, Sui-Xing; Lu, Wei; Zou, Jin; Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland 4072

    2013-08-12

    In this study, the structural quality of Au-catalyzed InAs nanowires grown by molecular beam epitaxy is investigated. Through detailed electron microscopy characterizations and analysis of binary Au-In phase diagram, it is found that defect-free InAs nanowires can be induced by smaller catalysts with a high In concentration, while comparatively larger catalysts containing less In induce defected InAs nanowires. This study indicates that the structural quality of InAs nanowires can be controlled by the size of Au catalysts when other growth conditions remain as constants.

  17. Nanowire-templated lateral epitaxial growth of non-polar group III nitrides

    DOE Patents [OSTI]

    Wang, George T. (Albuquerque, NM); Li, Qiming (Albuquerque, NM); Creighton, J. Randall (Albuquerque, NM)

    2010-03-02

    A method for growing high quality, nonpolar Group III nitrides using lateral growth from Group III nitride nanowires. The method of nanowire-templated lateral epitaxial growth (NTLEG) employs crystallographically aligned, substantially vertical Group III nitride nanowire arrays grown by metal-catalyzed metal-organic chemical vapor deposition (MOCVD) as templates for the lateral growth and coalescence of virtually crack-free Group III nitride films. This method requires no patterning or separate nitride growth step.

  18. Molecular Dynamics Simulation of GaAs Molecular Beam Epitaxy D. A. Murdick,1

    E-Print Network [OSTI]

    Wadley, Haydn

    of Virginia, Charlottesville, Virginia 22904, USA 2 Department of Materials, University of Oxford, Oxford OX1 3PH, UK ABSTRACT The vapor deposition of epitaxial GaAs and (Ga,Mn)As thin films during far-temperature growth of Ga0.94Mn0.06As and the Mn clustering trends in as-grown films. INTRODUCTION GaAs is widely used

  19. Response to ``Comment on `Reversible work of formation of an embryo of a new phase within a uniform macroscopic mother phase' '' J. Chem.

    E-Print Network [OSTI]

    in contact with a vapor such that the vapor phase pressure equals the drop's vapor pressure that is surrounded by a vapor in which the pressure of the vapor does not equal the vapor pressure of the droplet applies exclusively to liquid clusters formed in a vapor. Because of the large difference in density be

  20. 1-Dimensional Numerical Model of Thermal Conduction and Vapor Diffusion

    E-Print Network [OSTI]

    Schörghofer, Norbert

    developed by Samar Khatiwala, 2001 extended to variable thermal properties and irregular grid by Norbert Sch for c. Upper boundary condition: a) Radiation Q + k T z z=0 = T4 z=0 Q is the incoming solar flux of Water Vapor with Phase Transitions developed by Norbert Sch¨orghofer, 2003­2004 3 phases: vapor, free

  1. Low-temperature plasma-deposited silicon epitaxial films: Growth...

    Office of Scientific and Technical Information (OSTI)

    Low-temperature plasma-deposited silicon epitaxial films: Growth and properties Citation Details In-Document Search Title: Low-temperature plasma-deposited silicon epitaxial films:...

  2. Electrostatic Transfor of Patterned Epitaxial Graphene from SiC...

    Office of Scientific and Technical Information (OSTI)

    Electrostatic Transfor of Patterned Epitaxial Graphene from SiC (001) to Glass. Citation Details In-Document Search Title: Electrostatic Transfor of Patterned Epitaxial Graphene...

  3. VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA

    E-Print Network [OSTI]

    Rudnyi, Evgenii B.

    1 VAPORIZATION THERMODYNAMICS OF KCl. COMBINING VAPOR PRESSURE AND GRAVIMETRIC DATA Rudnyi E of thermodynamic properties of the vapor and the vaporization process, coupling pressure measurements. INTRODUCTION The vapor pressure of a substance is an important system property in many applications. Its value

  4. Vapor spill monitoring method

    DOE Patents [OSTI]

    Bianchini, Gregory M. (Livermore, CA); McRae, Thomas G. (Livermore, CA)

    1985-01-01

    Method for continuous sampling of liquified natural gas effluent from a spill pipe, vaporizing the cold liquified natural gas, and feeding the vaporized gas into an infrared detector to measure the gas composition. The apparatus utilizes a probe having an inner channel for receiving samples of liquified natural gas and a surrounding water jacket through which warm water is flowed to flash vaporize the liquified natural gas.

  5. Vapor Barriers or Vapor Diffusion Retarders | Department of Energy

    Energy Savers [EERE]

    vapor retarders: Class I vapor retarders (0.1 perms or less): Glass Sheet metal Polyethylene sheet Rubber membrane Class II vapor retarders (greater than 0.1 perms and less...

  6. Models of the formation of oxide phases in nanostructured materials based on lead chalcogenides subjected to treatment in oxygen and iodine vapors

    SciTech Connect (OSTI)

    Maraeva, E. V., E-mail: jenvmar@mail.ru; Moshnikov, V. A.; Tairov, Yu. M. [St. Petersburg State Electrotechnical University 'LETI' (Russian Federation)] [St. Petersburg State Electrotechnical University 'LETI' (Russian Federation)

    2013-10-15

    Model concepts concerning control over the formation of oxide layers during the course of oxidation are developed on the basis of experimental results of studies of systematic features of the formation of nanostructured layers after diffusion annealing. Data on a variation in the composition of oxide phases as the extent of deviation from stoichiometry is changed in the initial lead chalcogenide are presented. Model concepts related to the possibility of varying the thickness of the coating oxide phases using annealing in an oxygen-containing medium are developed. It is shown that annealing in an iodine atmosphere ensures the effective penetration of oxygen into the grains, which is necessary for an increase in the photoluminescence efficiency.

  7. Enthalpies of Vaporization and Vapor Pressures of Some Deuterated Hydrocarbons. Liquid-Vapor Pressure Isotope Effects

    E-Print Network [OSTI]

    Chickos, James S.

    Enthalpies of Vaporization and Vapor Pressures of Some Deuterated Hydrocarbons. Liquid-Vapor pressures as a function of temperature and enthalpies of vaporization of a series of both liquid and solid. The applicability of this technique is first demonstrated by reproducing the vapor pressure isotope effect

  8. Vapor Barriers or Vapor Diffusion Retarders | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    retarders. Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor...

  9. Process for forming epitaxial perovskite thin film layers using halide precursors

    DOE Patents [OSTI]

    Clem, Paul G. (Albuquerque, NM); Rodriguez, Mark A. (Albuquerque, NM); Voigt, James A. (Corrales, NM); Ashley, Carol S. (Albuquerque, NM)

    2001-01-01

    A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

  10. The use of DRIFTS-MS and kinetic studies to determine the role of acetic acid in the palladium-catalyzed vapor-phase synthesis of vinyl acetate

    SciTech Connect (OSTI)

    Augustine, S.M.; Blitz, J.P. (Quantum Chemical Corp., Cincinnati, OH (United States))

    1993-07-01

    Supported palladium catalyzes the synthesis of vinyl acetate (VA) by oxyacetylation of ethylene. Alkali promoters increase activity and selectivity. The role of acetic acid (HOAc) in these processes is not well understood. Activation energy studies show that HOAc alters the catalyst site and lowers the reaction barrier to VA formation. After correction for this effect, the kinetics reveal that as a reagent HOAc is zero order. This is probably due to a strong adsorption of HOAc and Pd which forms the catalyst active phase. Detailed spectroscopic studies support this conclusion. The surface processes on a supported vinyl acetate catalyst were studied using a method which couples diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with mass spectrometry (MS). The DRIFTS-MS technique combines the capability of selectively analyzing IR-active surface species with sensitive detection of transient reaction products. By comparing the catalyst with mixtures of palladium acetate powder physically dispersed in potassium chloride, it is determined that the active phase on the catalyst is a form of palladium acetate. Compound formation is consistent with the strong chemisorption of HOAc on Pd. Kinetic analysis of temperature-programmed reaction(TPRxn) data suggests that Pd metal or metal oxide adjacent to the active site is important in the reaction mechanism. 25 refs., 10 figs., 2 tabs.

  11. Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition

    SciTech Connect (OSTI)

    Anders, Andre

    2010-11-26

    The chemistry, microstructure, and catalytic activity of thin films incorporating palladium were studied using scanning and transmission electron microscopies, X-ray diffraction, spectrophotometry, 4-point probe and catalytic tests. The films were synthesized using pulsed filtered cathodic arc and magnetron sputter deposition, i.e. techniques far from thermodynamic equilibrium. Catalytic particles were formed by thermally cycling thin films of the Pd-Pt-O system. The evolution and phase formation in such films as a function of temperature were discussed in terms of the stability of PdO and PtO2 in air. The catalytic efficiency was found to be strongly affected by the chemical composition, with oxidized palladium definitely playing a major role in the combustion of methane. Reactive sputter deposition of thin films in the Pd-Zr-Y-O system allowed us forming microstructures ranging from nanocrystalline zirconia to palladium nanoparticles embedded in a (Zr,Y)4Pd2O matrix. The sequence of phase formation is put in relation to simple thermodynamic considerations.

  12. Heat transfer during film condensation of potassium vapor

    E-Print Network [OSTI]

    Kroger, Detlev Gustav

    1966-01-01

    The object of this work is to investigate theoretically and experimentally the following two phases of heat transfer during condensation of potassium vapore, a. Heat transfer during film condensation of pure saturated ...

  13. Laboratory test plan in-well vapor stripping system

    SciTech Connect (OSTI)

    Koegler, K.J

    1994-07-01

    This test plan describes the activities that will be conducted as a part of the laboratory testing of a full-scale mockup of the Stanford in-well vapor stripping system. These tests will be conducted to delineate design parameters for the in-well vapor stripping unit and to identify and quantify variables that are sensitive to the dynamic hydraulic effects induced by operation of the system. No radioactive materials are involved in this test. In-well vapor stripping has been used successfully as an alternative to conventional pump-and-treat technology for remediation of volatile organic compound (VOC) contaminated groundwater in Europe and more recently in the United States. In-well vapor stripping permits in situ remediation of VOC-contaminated groundwater by combining an in-well vapor stripping system with a treatment well is used to extract and discharge groundwater simultaneously, resulting in the establishment of a vertical circulation groundwater flow cell in the aquifer. Groundwater extracted from the aquifer via the lower screened interval is treated for VOCs by in-well vapor stripping within the treatment well. This stripping causes aqueous phase VOCs to partition preferentially into a vapor phase. Treated groundwater is discharged back to the aquifer via the upper screened interval of the treatment well, while the vapor phase VOCs are simultaneously removed from the well bore and contained at the surface with a vacuum extraction system. Groundwater entrained into the vertical circulation flow cell becomes sequentially cleaned of VOC contamination in an efficient manner without the need for surface treatment and handling of contaminated groundwater. An added benefit of in-well vapor stripping is the ability to perform vadose zone vapor extraction concurrently with groundwater remediation. This uses the vacuum extraction capabilities of the in-well vapor stripping configured with the upper screened interval placed into the vadose zone above the water table.

  14. Epitaxial growth of silicon for layer transfer

    DOE Patents [OSTI]

    Teplin, Charles; Branz, Howard M

    2015-03-24

    Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

  15. Atomic vapor laser isotope separation

    SciTech Connect (OSTI)

    Stern, R.C.; Paisner, J.A.

    1986-08-15

    The atomic vapor laser isotope separation (AVLIS) process for the enrichment of uranium is evaluated. (AIP)

  16. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Substrate-Induced Band-Gap Opening in Epitaxial Graphene Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Wednesday, 26 March 2008 00:00 Prospective challengers to...

  17. Electrolyte vapor condenser

    DOE Patents [OSTI]

    Sederquist, Richard A. (Newington, CT); Szydlowski, Donald F. (East Hartford, CT); Sawyer, Richard D. (Canton, CT)

    1983-01-01

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

  18. Electrolyte vapor condenser

    DOE Patents [OSTI]

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  19. Experimental and Modeling Study of the Flammability of Fuel Tank Headspace Vapors from Ethanol/Gasoline Fuels; Phase 3: Effects of Winter Gasoline Volatility and Ethanol Content on Blend Flammability; Flammability Limits of Denatured Ethanol

    SciTech Connect (OSTI)

    Gardiner, D. P.; Bardon, M. F.; Clark, W.

    2011-07-01

    This study assessed differences in headspace flammability for summertime gasolines and new high-ethanol content fuel blends. The results apply to vehicle fuel tanks and underground storage tanks. Ambient temperature and fuel formulation effects on headspace vapor flammability of ethanol/gasoline blends were evaluated. Depending on the degree of tank filling, fuel type, and ambient temperature, fuel vapors in a tank can be flammable or non-flammable. Pure gasoline vapors in tanks generally are too rich to be flammable unless ambient temperatures are extremely low. High percentages of ethanol blended with gasoline can be less volatile than pure gasoline and can produce flammable headspace vapors at common ambient temperatures. The study supports refinements of fuel ethanol volatility specifications and shows potential consequences of using noncompliant fuels. E85 is flammable at low temperatures; denatured ethanol is flammable at warmer temperatures. If both are stored at the same location, one or both of the tanks' headspace vapors will be flammable over a wide range of ambient temperatures. This is relevant to allowing consumers to splash -blend ethanol and gasoline at fueling stations. Fuels compliant with ASTM volatility specifications are relatively safe, but the E85 samples tested indicate that some ethanol fuels may produce flammable vapors.

  20. Epitaxial graphene on silicon carbide: Introduction to structured graphene

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Epitaxial graphene on silicon carbide: Introduction to structured graphene Ming Ruan 1 , Yike Hu 1, France Abstract We present an introduction to the rapidly growing field of epitaxial graphene on silicon present, highly evolved state. The potential of epitaxial graphene as a new electronic material is now

  1. Organic vapor jet printing system

    DOE Patents [OSTI]

    Forrest, Stephen R

    2012-10-23

    An organic vapor jet printing system includes a pump for increasing the pressure of an organic flux.

  2. GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a

    E-Print Network [OSTI]

    Atwater, Harry

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a Daniel C, crack-free GaInP/GaAs double junction solar cells were grown by metal organic chemical vapor deposition with the world record efficiency is a metamorphic triple junction GaInP/GaAs/Ge cell.6 Alternatively, wafer

  3. Analysis of strain relaxation by microcracks in epitaxial GaAs grown on Ge/Si substrates

    SciTech Connect (OSTI)

    Colombo, D.; Grilli, E.; Guzzi, M.; Sanguinetti, S.; Marchionna, S.; Bonfanti, M.; Fedorov, A.; Kaenel, H. von; Isella, G.; Mueller, E. [CNISM and L-NESS, Dipartimento di Scienza dei Materiali, Universita di Milano Bicocca, Via Cozzi 53, I-20125, Milano (Italy); CNISM and L-NESS, Dipartimento di Fisica del Politecnico di Milano, Polo di Como, via Anzani 52, I-22100 Como (Italy); Laboratorium fuer Festkoerperphysik, ETH Zuerich, CH-8093 Zuerich (Switzerland)

    2007-05-15

    A detailed spectroscopic and morphological study of GaAs epitaxial layers grown by molecular beam epitaxy on Ge buffer layers deposited by low energy plasma enhanced chemical vapor deposition on Si is presented. The aim is to understand the nature of thermal strain relaxation induced by crack formation in the epilayers. The comparison of the experimental data on the spatial strain relaxation pattern with the theoretical prediction from a purely elastic model indicates that strain relaxation around cracks arises from two contributions. At short distances the main contribution is essentially plastic, due to the presence of extended defects. At large distances, on the contrary, elastic relaxation seems to dominate. It is also shown that GaAs grown on Ge/Si substrates is in a state of metastable strain as a consequence of the fact that cracks relax the thermal tensile strain only locally.

  4. Proximity-induced giant spin-orbit interaction in epitaxial graphene on topological insulator

    E-Print Network [OSTI]

    Jin, Kyung-Hwan

    2015-01-01

    Heterostructures of Dirac materials such as graphene and topological insulators provide interesting platforms to explore exotic quantum states of electrons in solids. Here we study the electronic structure of graphene-Sb2Te3 heterostructure using density functional theory and tight-binding methods. We show that the epitaxial graphene on Sb2Te3 turns into quantum spin-Hall phase due to its proximity to the topological insulating Sb2Te3. It is found that the epitaxial graphene develops a giant spin-orbit gap of about ~20 meV, which is about three orders of magnitude larger than that of pristine graphene. We discuss the origin of such enhancement of the spin-orbit interaction and possible outcomes of the spin-Hall phase in graphene.

  5. In-well vapor stripping drilling and characterization work plan

    SciTech Connect (OSTI)

    Koegler, K.J.

    1994-03-13

    This work plan provides the information necessary for drilling, sampling, and hydrologic testing of wells to be completed in support of a demonstration of the in-well vapor stripping system. The in-well vapor stripping system is a remediation technology designed to preferentially extract volatile organic compounds (VOCs) from contaminated groundwater by converting them to a vapor phase. Air-lift pumping is used to lift and aerate groundwater within the well. The volatiles escaping the aerated water are drawn off by a slight vacuum and treated at the surface while the water is allowed to infiltrate the vadose zone back to the watertable.

  6. Stratified vapor generator

    DOE Patents [OSTI]

    Bharathan, Desikan (Lakewood, CO); Hassani, Vahab (Golden, CO)

    2008-05-20

    A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).

  7. The vapor pressures of explosives

    SciTech Connect (OSTI)

    Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

    2013-01-05

    The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

  8. Recovery of oscillatory magneto-resistance in phase separated La{sub 0.3}Pr{sub 0.4}Ca{sub 0.3}MnO{sub 3} epitaxial thin films

    SciTech Connect (OSTI)

    Alagoz, H. S., E-mail: alagoz@ualberta.ca; Jeon, J.; Mahmud, S. T.; Saber, M. M.; Chow, K. H., E-mail: khchow@ualberta.ca; Jung, J., E-mail: jjung@ualberta.ca [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada); Prasad, B. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)] [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom); Egilmez, M. [Department of Physics, American University of Sharjah, Sharjah (United Arab Emirates)] [Department of Physics, American University of Sharjah, Sharjah (United Arab Emirates)

    2013-12-02

    In-plane angular dependent magneto-resistance has been studied in La{sub 0.3}Pr{sub 0.4}Ca{sub 0.3}MnO{sub 3} (LPCMO) manganite thin films deposited on the (100) oriented NdGaO{sub 3}, and (001) oriented SrTiO{sub 3} and LaAlO{sub 3} substrates. At temperatures where the electronic phase separation is the strongest, a metastable irreversible state exists in the films whose resistivity ? attains a large time dependent value. The ? decreases sharply with an increasing angle ? between the magnetic field and the current, and does not display an expected oscillatory cos{sup 2}?/sin{sup 2}? dependence for all films. The regular oscillations are recovered during repetitive sweeping of ? between 0° and 180°. We discuss possible factors that could produce these unusual changes in the resistivity.

  9. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    SciTech Connect (OSTI)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  10. Production of higher quality bio-oils by in-line esterification of pyrolysis vapor

    DOE Patents [OSTI]

    Hilten, Roger Norris; Das, Keshav; Kastner, James R; Bibens, Brian P

    2014-12-02

    The disclosure encompasses in-line reactive condensation processes via vapor phase esterification of bio-oil to decease reactive species concentration and water content in the oily phase of a two-phase oil, thereby increasing storage stability and heating value. Esterification of the bio-oil vapor occurs via the vapor phase contact and subsequent reaction of organic acids with ethanol during condensation results in the production of water and esters. The pyrolysis oil product can have an increased ester content and an increased stability when compared to a condensed pyrolysis oil product not treated with an atomized alcohol.

  11. Vapor Transport in Dry Soils

    SciTech Connect (OSTI)

    Gee, Glendon W.; Ward, Anderson L.

    2001-11-16

    Water-vapor movement in soils is a complex process, controlled by both diffusion and advection and influenced by pressure and thermal gradients acting across tortuous flow paths. Wide-ranging interest in water-vapor transport includes both theoretical and practical aspects. Just how pressure and thermal gradients enhance water-vapor flow is still not completely understood and subject to ongoing research. Practical aspects include dryland farming (surface mulching), water harvesting (aerial wells), fertilizer placement, and migration of contaminants at waste-sites. The following article describes the processes and practical applications of water-vapor transport, with emphasis on unsaturated (dry) soil systems.

  12. Junction Transport in Epitaxial Film Silicon Heterojunction Solar Cells

    SciTech Connect (OSTI)

    Young, D. L.; Li, J. V.; Teplin, C. W.; Stradins, P.; Branz, H. M.

    2011-01-01

    We report our progress toward low-temperature HWCVD epitaxial film silicon solar cells on inexpensive seed layers, with a focus on the junction transport physics exhibited by our devices. Heterojunctions of i/p hydrogenated amorphous Si (a-Si) on our n-type epitaxial crystal Si on n{sup ++} Si wafers show space-charge-region recombination, tunneling or diffusive transport depending on both epitaxial Si quality and the applied forward voltage.

  13. Junction Transport in Epitaxial Film Silicon Heterojunction Solar Cells: Preprint

    SciTech Connect (OSTI)

    Young, D. L.; Li, J. V.; Teplin, C. W.; Stradins, P.; Branz, H. M.

    2011-07-01

    We report our progress toward low-temperature HWCVD epitaxial film silicon solar cells on inexpensive seed layers, with a focus on the junction transport physics exhibited by our devices. Heterojunctions of i/p hydrogenated amorphous Si (a-Si) on our n-type epitaxial crystal Si on n++ Si wafers show space-charge-region recombination, tunneling or diffusive transport depending on both epitaxial Si quality and the applied forward voltage.

  14. Vapor spill pipe monitor

    DOE Patents [OSTI]

    Bianchini, G.M.; McRae, T.G.

    1983-06-23

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

  15. Substrate-Induced Band-Gap Opening in Epitaxial Graphene

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Substrate-Induced Band-Gap Opening in Epitaxial Graphene Print Prospective challengers to silicon, the long-reigning king of semiconductors for computer chips and other electronic...

  16. Controlled Covalent Modification of Epitaxial Single Layer Graphene...

    Office of Scientific and Technical Information (OSTI)

    Controlled Covalent Modification of Epitaxial Single Layer Graphene on 6H-SiC (0001) with Aryliodonium Salts using Electrochemical Methods. Citation Details In-Document Search...

  17. Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial...

    Office of Scientific and Technical Information (OSTI)

    Growth Mode and Substrate Symmetry Dependent Strain in Epitaxial Graphene. Citation Details In-Document Search Title: Growth Mode and Substrate Symmetry Dependent Strain in...

  18. Characterization and Comparison of Devices Fabricated From Epitaxial...

    Office of Scientific and Technical Information (OSTI)

    Characterization and Comparison of Devices Fabricated From Epitaxial Graphene on SiC and Electrostatically Transferred Graphene. Citation Details In-Document Search Title:...

  19. Method of deposition by molecular beam epitaxy

    DOE Patents [OSTI]

    Chalmers, S.A.; Killeen, K.P.; Lear, K.L.

    1995-01-10

    A method is described for reproducibly controlling layer thickness and varying layer composition in an MBE deposition process. In particular, the present invention includes epitaxially depositing a plurality of layers of material on a substrate with a plurality of growth cycles whereby the average of the instantaneous growth rates for each growth cycle and from one growth cycle to the next remains substantially constant as a function of time. 9 figures.

  20. Electron holography of devices with epitaxial layers

    SciTech Connect (OSTI)

    Gribelyuk, M. A. Ontalus, V.; Baumann, F. H.; Zhu, Z.; Holt, J. R.

    2014-11-07

    Applicability of electron holography to deep submicron Si devices with epitaxial layers is limited due to lack of the mean inner potential data and effects of the sample tilt. The mean inner potential V{sub 0}?=?12.75?V of the intrinsic epitaxial SiGe was measured by electron holography in devices with Ge content C{sub Ge}?=?18%. Nanobeam electron diffraction analysis performed on the same device structure showed that SiGe is strain-free in [220] direction. Our results showed good correlation with simulations of the mean inner potential of the strain-free SiGe using density function theory. A new method is proposed in this paper to correct electron holography data for the overlap of potentials of Si and the epitaxial layer, which is caused by the sample tilt. The method was applied to the analysis of the dopant diffusion in p-Field-effect Transistor devices with the identical gate length L?=?30?nm, which had alternative SiGe geometry in the source and drain regions and was subjected to different thermal processing. Results have helped to understand electrical data acquired from the same devices in terms of dopant diffusion.

  1. A Minimal Model for Large-scale Epitaxial Growth Kinetics of Graphene

    E-Print Network [OSTI]

    Jiang, Huijun

    2015-01-01

    Epitaxial growth via chemical vapor deposition is considered to be the most promising way towards synthesizing large area graphene with high quality. However, it remains a big theoretical challenge to reveal growth kinetics with atomically energetic and large-scale spatial information included. Here, we propose a minimal kinetic Monte Carlo model to address such an issue on an active catalyst surface with graphene/substrate lattice mismatch, which facilitates us to perform large scale simulations of the growth kinetics over two dimensional surface with growth fronts of complex shapes. A geometry-determined large-scale growth mechanism is revealed, where the rate-dominating event is found to be $C_{1}$-attachment for concave growth front segments and $C_{5}$-attachment for others. This growth mechanism leads to an interesting time-resolved growth behavior which is well consistent with that observed in a recent scanning tunneling microscopy experiment.

  2. Vapor Pressures and Vaporization Enthalpies of a Series of Dialkyl Phthalates by Correlation Gas Chromatography

    E-Print Network [OSTI]

    Chickos, James S.

    Vapor Pressures and Vaporization Enthalpies of a Series of Dialkyl Phthalates by Correlation Gas: Experimental vapor pressures, vaporization, fusion and sublimation enthalpies of a number of dialkyl, dibutyl phthalate, and bis(2-ethylhexyl) phthalate. New vaporization enthalpies and liquid vapor pressure

  3. The Vaporization Enthalpies and Vapor Pressures of Some Primary Amines of Pharmaceutical Importance by Correlation Gas

    E-Print Network [OSTI]

    Chickos, James S.

    The Vaporization Enthalpies and Vapor Pressures of Some Primary Amines of Pharmaceutical Importance Information ABSTRACT: Vapor pressures, vaporization, and sublimation enthalpies of several pharmaceuticals.5 ± 2.1); p(cr)/Pa = 0.12 ± 0.04]. Vapor pressure equations also derived from vapor pressureretention

  4. Static atomic displacements in a CdTe epitaxial layer on a GaAs substrate

    SciTech Connect (OSTI)

    Horning, R.D.; Staudenmann, J.

    1987-05-25

    A (001)CdTe epitaxial layer on a (001)GaAs substrate was studied by x-ray diffraction between 10 and 360 K. The CdTe growth took place at 380 /sup 0/C in a vertical gas flow metalorganic chemical vapor deposition reactor. Lattice parameters and integrated intensities of both the substrate and the epitaxial layer using the (00l) and (hhh) Bragg reflections reveal three important features. Firstly, the GaAs substrate does not exhibit severe strain after deposition and it is as perfect as a bulk GaAs. Secondly, the CdTe unit cell distorts tetragonally with a/sub perpendicular/>a/sub parallel/ below 300 K. The decay of the (00l) reflection intensities as a function of the temperature yields a Debye temperature of 142 K, the same value as for bulk CdTe. Thirdly, a temperature-dependent isotropic static displacement of the Cd and the Te atoms is introduced to account for the anomalous behavior of the (hhh) intensities.

  5. An Examination of the Thermodynamics of Fusion, Vaporization, and Sublimation of Several Parabens by Correlation Gas

    E-Print Network [OSTI]

    Chickos, James S.

    on their thermochemical properties. A number of studies have reported measurements of their phase change enthalpies.com). DOI 10.1002/jps.22423 ABSTRACT: The vaporization, fusion, and sublimation enthalpies of methyl, ethyl, propyl, and butyl paraben are reported and compared with literature values. The vaporization enthalpies

  6. Thermodynamic analysis and growth of ZrO2 by chloride chemical vapor deposition

    E-Print Network [OSTI]

    Anderson, Timothy J.

    for the chemical vapor deposition (CVD) of zirconia. The results showed zirconia formation would occur at high) and high temperatures (N800 °C). Using these calculations as a guide, single-phase monoclinic zirconia.46 mg cm-2 h-1 . © 2007 Elsevier B.V. All rights reserved. Keywords: Chemical vapor deposition; Zirconia

  7. Effects of substrate temperature and Cu underlayer thickness on the formation of SmCo{sub 5}(0001) epitaxial thin films

    SciTech Connect (OSTI)

    Ohtake, Mitsuru; Nukaga, Yuri; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-05-15

    SmCo{sub 5}(0001) epitaxial thin films were prepared on Cu(111) underlayers heteroepitaxially grown on Al{sub 2}O{sub 3}(0001) single-crystal substrates by molecular beam epitaxy. The effects of substrate temperature and Cu underlayer thickness on the crystallographic properties of SmCo{sub 5}(0001) epitaxial films were investigated. The Cu atoms of underlayer diffuse into the SmCo{sub 5} film and substitute the Co sites in SmCo{sub 5} structure forming an alloy compound of Sm(Co,Cu){sub 5}. The ordered phase formation is enhanced with increasing the substrate temperature and with increasing the Cu underlayer thickness. The Cu atom diffusion into the SmCo{sub 5} film is assisting the formation of Sm(Co,Cu){sub 5} ordered phase.

  8. Method of physical vapor deposition of metal oxides on semiconductors

    DOE Patents [OSTI]

    Norton, David P. (Knoxville, TN)

    2001-01-01

    A process for growing a metal oxide thin film upon a semiconductor surface with a physical vapor deposition technique in a high-vacuum environment and a structure formed with the process involves the steps of heating the semiconductor surface and introducing hydrogen gas into the high-vacuum environment to develop conditions at the semiconductor surface which are favorable for growing the desired metal oxide upon the semiconductor surface yet is unfavorable for the formation of any native oxides upon the semiconductor. More specifically, the temperature of the semiconductor surface and the ratio of hydrogen partial pressure to water pressure within the vacuum environment are high enough to render the formation of native oxides on the semiconductor surface thermodynamically unstable yet are not so high that the formation of the desired metal oxide on the semiconductor surface is thermodynamically unstable. Having established these conditions, constituent atoms of the metal oxide to be deposited upon the semiconductor surface are directed toward the surface of the semiconductor by a physical vapor deposition technique so that the atoms come to rest upon the semiconductor surface as a thin film of metal oxide with no native oxide at the semiconductor surface/thin film interface. An example of a structure formed by this method includes an epitaxial thin film of (001)-oriented CeO.sub.2 overlying a substrate of (001) Ge.

  9. Development of Production PVD-AIN Buffer Layer System and Processes to Reduce Epitaxy Costs and Increase LED Efficiency

    SciTech Connect (OSTI)

    Cerio, Frank

    2013-09-14

    The DOE has set aggressive goals for solid state lighting (SSL) adoption, which require manufacturing and quality improvements for virtually all process steps leading to an LED luminaire product. The goals pertinent to this proposed project are to reduce the cost and improve the quality of the epitaxial growth processes used to build LED structures. The objectives outlined in this proposal focus on achieving cost reduction and performance improvements over state-of-the-art, using technologies that are low in cost and amenable to high efficiency manufacturing. The objectives of the outlined proposal focus on cost reductions in epitaxial growth by reducing epitaxy layer thickness and hetero-epitaxial strain, and by enabling the use of larger, less expensive silicon substrates and would be accomplished through the introduction of a high productivity reactive sputtering system and an effective sputtered aluminum-nitride (AlN) buffer/nucleation layer process. Success of the proposed project could enable efficient adoption of GaN on-silicon (GaN/Si) epitaxial technology on 150mm silicon substrates. The reduction in epitaxy cost per cm{sup 2} using 150mm GaN-on-Si technology derives from (1) a reduction in cost of ownership and increase in throughput for the buffer deposition process via the elimination of MOCVD buffer layers and other throughput and CoO enhancements, (2) improvement in brightness through reductions in defect density, (3) reduction in substrate cost through the replacement of sapphire with silicon, and (4) reduction in non-ESD yield loss through reductions in wafer bow and temperature variation. The adoption of 150mm GaN/Si processing will also facilitate significant cost reductions in subsequent wafer fabrication manufacturing costs. There were three phases to this project. These three phases overlap in order to aggressively facilitate a commercially available production GaN/Si capability. In Phase I of the project, the repeatability of the performance was analyzed and improvements implemented to the Veeco PVD-AlN prototype system to establish a specification and baseline PVD-AlN films on sapphire and in parallel the evaluation of PVD AlN on silicon substrates began. In Phase II of the project a Beta tool based on a scaled-up process module capable of depositing uniform films on batches of 4”or 6” diameter substrates in a production worthy operation was developed and qualified. In Phase III, the means to increase the throughput of the PVD-AlN system was evaluated and focused primarily on minimizing the impact of the substrate heating and cooling times that dominated the overall cycle time.

  10. Vaporization Enthalpy and Vapor Pressure of Valproic Acid by Correlation Gas Chromatography

    E-Print Network [OSTI]

    Chickos, James S.

    Vaporization Enthalpy and Vapor Pressure of Valproic Acid by Correlation Gas Chromatography Joe A-propylpentanoic acid) is reported, and the vapor pressures of a series on aliphatic carboxylic acids are used to evaluate its vapor pressure as a function of temperature. The vaporization enthalpy was derived

  11. Z .Fluid Phase Equilibria 161 1999 241256 Vaporliquid equilibrium, fluid state, and zero-pressure solid

    E-Print Network [OSTI]

    Lisal, Martin

    Z .Fluid Phase Equilibria 161 1999 241­256 Vapor­liquid equilibrium, fluid state, and zero-pressure but independent constant pressure­constant temperature Z .molecular dynamics simulations of the vapor and liquid. Keywords: Chlorine; Intermolecular potential; Molecular simulation; Vapor­liquid equilibria; Vapor pressure

  12. Epitaxial YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}/Sr{sub 2}RuO{sub 4} heterostructures

    SciTech Connect (OSTI)

    Schlom, D.G.; Merritt, B.A.; Madhavan, S. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering] [and others

    1997-09-01

    The anisotropic oxide superconductors YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Sr{sub 2}RuO{sub 4} have been epitaxially combined in various ways (c-axis on c-axis, c-axis on a-axis, and a-axis on a-axis) though the use of appropriate substrates. Phase-pure a-axis oriented or c-axis oriented epitaxial Sr{sub 2}RuO{sub 4} films were grown by pulsed laser deposition. YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films were then grown on both orientations of Sr{sub 2}RuO{sub 4} films and the resulting epitaxy was characterized.

  13. Adsorption of radon and water vapor on commercial activated carbons

    SciTech Connect (OSTI)

    Hassan, N.M. [Westinghouse Savannah River Co., Aiken, SC (United States); Ghosh, T.K.; Hines, A.L.; Loyalka, S.K. [Univ. of Missouri, Columbia, MO (United States)

    1995-02-01

    Equilibrium adsorption isotherms are reported for radon and water vapor on two commercial activated carbons: coconut shell Type PCB and hardwood Type BD. The isotherms of the water vapor were measured gravimetrically at 298 K. The isotherms of radon from dry nitrogen were obtained at 293, 298, and 308 K while the data for the mixture of radon and water vapor were measured at 298 K. The concentrations of radon in the gas and solid phases were measured simultaneously, once the adsorption equilibrium and the radioactive equilibrium between the radon and its daughter products were established. The shape of the isotherms was of Type III for the radon and Type V for the water vapor, according to Brunauer`s classification. The adsorption mechanism was similar for both the radon and the water vapor, being physical adsorption on the macropore surface area in the low pressure region and micropore filling near saturation pressure. The uptake capacity of radon decreased both with increasing temperature and relative humidity. The heat of adsorption data indicated that the PCB- and the BD-activated carbons provided a heterogeneous surface for radon adsorption. The equilibrium data for radon were correlated with a modified Freundlich equation.

  14. Hetero-epitaxy of perovskite oxides on GaAs(001) by molecular beam epitaxy

    SciTech Connect (OSTI)

    Liang, Y.; Kulik, J.; Eschrich, T.C.; Droopad, R.; Yu, Z.; Maniar, P. [Microelectronics and Physical Sciences Laboratory, Process and Materials Characterization Laboratory, and Microelectronics and Physical Sciences Laboratory, Motorola Inc., 2100 East Elliot Road, Tempe, Arizona 85284 (United States)

    2004-08-16

    Hetero-epitaxy of single-crystal perovskite SrTiO{sub 3} on GaAs(001) was achieved using molecular beam epitaxy. The growth was accomplished by deposition of a submonolayer of titanium on GaAs(001), followed by the co-deposition of strontium and titanium initiated at a low-temperature, low-oxygen-pressure condition. X-ray photoelectron spectroscopy showed that the Ti prelayer reacted with As and formed TiAs-like species on the As terminated GaAs(001) surface. Reflection-high-energy-electron diffraction showed that SrTiO{sub 3} grew coherently on the GaAs(001) at early stage of growth. This coherent behavior began to degrade when SrTiO{sub 3} thickness exceeded 20 A ring . Cross-sectional transmission electron microscopy revealed an abrupt interface between SrTiO{sub 3} and GaAs and good crystallinity of the SrTiO{sub 3} film. An epitaxial relationship between SrTiO{sub 3} and GaAs was further confirmed by x-ray diffraction. The success of growth of SrTiO{sub 3} on GaAs paves the way for integration of various functional perovskite oxides with GaAs.

  15. Resistance switching in epitaxial SrCoO{sub x} thin films

    SciTech Connect (OSTI)

    Tambunan, Octolia T.; Parwanta, Kadek J.; Acharya, Susant K.; Lee, Bo Wha; Jung, Chang Uk; Kim, Yeon Soo; Park, Bae Ho; Jeong, Huiseong; Park, Ji-Yong; Cho, Myung Rae; Park, Yun Daniel; Choi, Woo Seok; Kim, Dong-Wook; Jin, Hyunwoo; Lee, Suyoun; Song, Seul Ji; Kang, Sung-Jin; Kim, Miyoung; Hwang, Cheol Seong

    2014-08-11

    We observed bipolar switching behavior from an epitaxial strontium cobaltite film grown on a SrTiO{sub 3} (001) substrate. The crystal structure of strontium cobaltite has been known to undergo topotactic phase transformation between two distinct phases: insulating brownmillerite (SrCoO{sub 2.5}) and conducting perovskite (SrCoO{sub 3??}) depending on the oxygen content. The current–voltage characteristics of the strontium cobaltite film showed that it could have a reversible insulator-to-metal transition triggered by electrical bias voltage. We propose that the resistance switching in the SrCoO{sub x} thin film could be related to the topotactic phase transformation and the peculiar structure of SrCoO{sub 2.5}.

  16. Vaporization Enthalpies and Vapor Pressures of Two Insecticide Components, Muscalure and Empenthrin, by Correlation Gas

    E-Print Network [OSTI]

    Chickos, James S.

    Vaporization Enthalpies and Vapor Pressures of Two Insecticide Components, Muscalure and Empenthrin: The vaporization enthalpies at T/K = 298.15 and vapor pressures from T/K = (298.15 to Tnb (normal boiling. Vaporization enthalpies of [(114.4 ± 1.0) and (114.5 ± 1.0)] kJ·mol-1 and vapor pressures, p/Pa = [(1.2 ± 0

  17. Self-doping effects in epitaxially grown graphene

    E-Print Network [OSTI]

    Siegel, David A.

    2009-01-01

    The electronic properties of graphene, Rev. Mod. Phys. (inE?ects in Epitaxially-Grown Graphene D.A. Siegel, 1, 2 S.Y.2009) Abstract Self-doping in graphene has been studied by

  18. Role of carbon surface diffusion and strain on the epitaxial...

    Office of Scientific and Technical Information (OSTI)

    Role of carbon surface diffusion and strain on the epitaxial growth of graphene on SiC(0001). Citation Details In-Document Search Title: Role of carbon surface diffusion and strain...

  19. Sol-gel-derived Epitaxial Nanocomposite Thin Films with Large...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sol-gel-derived Epitaxial Nanocomposite Thin Films with Large Sharp Magnetoelectric Effect Home Author: B. Liu, T. Sun, J. He, V. P. Dravid Year: 2010 Abstract: Nanostructures of...

  20. Vapor deposition of thin films

    DOE Patents [OSTI]

    Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  1. Vapor deposition of thin films

    SciTech Connect (OSTI)

    Smith, D.C.; Pattillo, S.G.; Laia, J.R. Jr.; Sattelberger, A.P.

    1990-10-05

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl){sub 3}, iridium(allyl){sub 3}, molybdenum(allyl){sub 4}, tungsten(allyl){sub 4}, rhenium (allyl){sub 4}, platinum(allyl){sub 2}, or palladium(allyl){sub 2} are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  2. Development of epitaxial AlxSc1-xN for artificially structured metal/semiconductor superlattice metamaterials

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The AlxSc1-xN alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x more »the rocksalt phase has been extended to x xSc1-xN alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt AlxSc1-xN alloys enable high quality epitaxial rocksalt metal/AlxSc1-xN superlattices with a wide range of accessible metamaterials properties.« less

  3. Vapor generation methods for explosives detection research

    SciTech Connect (OSTI)

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2012-12-01

    The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

  4. Surface and Interface Properties of 10–12 Unit Cells Thick Sputter Deposited Epitaxial CeO 2 Films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Saraf, L. V.; Wang, C. M.; Engelhard, M. H.; Nachimuthu, P.

    2008-01-01

    Ultrathin and continuous epitaxial films with relaxed lattice strain can potentially maintain more of its bulk physical and chemical properties and are useful as buffer layers. We study surface, interface, and microstructural properties of ultrathin ( ? 10–12 unit cells thick) epitaxial ceria films grown on single crystal YSZ substrates. The out-of -plane and in-plane lattice parameters indicate relaxation in the continuous film due to misfit dislocations seen by high-resolution transmission electron microscopy (HRTEM) and substrate roughness of ? 1-2 unit cells, confirmed by atomic force microscopy and HRTEM. A combination of secondary sputtering, latticemore »mismatch, substrate roughness, and surface reduction creating secondary phase was likely the cause of surface roughness which should be reduced to a minimum level for effective use of it as buffer layers. « less

  5. Superconducting epitaxial thin films of CeNi{sub x}Bi{sub 2} with a bismuth square net structure

    SciTech Connect (OSTI)

    Buckow, Alexander; Kupka, Katharina; Retzlaff, Reiner; Kurian, Jose; Alff, Lambert [Institute of Materials Science, Technische Universitaet Darmstadt, 64287 Darmstadt (Germany)

    2012-10-15

    We have grown highly epitaxial and phase pure thin films of the arsenic-free pnictide compound CeNi{sub x}Bi{sub 2} on (100) MgO substrates by reactive molecular beam epitaxy (RMBE). X-ray diffraction and reflection high-energy electron diffraction of the films confirm the ZrCuSiAs structure with a Bi square net layer. Superconductivity was observed in magnetization and resistivity measurements for x= 0.75 to 0.93 in these CeNi{sub x}Bi{sub 2} thin films with the highest critical temperature of 4.05 K and a resistive transition width of 0.1 K for x= 0.86. Our results indicate that thin film deposition by RMBE provides a tool to synthesize high-quality pnictide superconductors of the novel 112 type.

  6. Vacuum vapor deposition gun assembly

    DOE Patents [OSTI]

    Zeren, Joseph D. (Boulder, CO)

    1985-01-01

    A vapor deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, a hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  7. Atomic vapor laser isotope separation process

    DOE Patents [OSTI]

    Wyeth, R.W.; Paisner, J.A.; Story, T.

    1990-08-21

    A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.

  8. Vapor Pressures and Vaporization, Sublimation, and Fusion Enthalpies of Some Fatty Acids

    E-Print Network [OSTI]

    Chickos, James S.

    Vapor Pressures and Vaporization, Sublimation, and Fusion Enthalpies of Some Fatty Acids Joe A vapor pressures of both the subcooled liquid and solid state for those materials that are solids at T/K = 298.15. Equations for the prediction of vapor pressure from T/K = 298.15 to the boiling temperature

  9. Piloting epitaxy with ellipsometry as an in-situ sensor technology

    E-Print Network [OSTI]

    Warnick, Sean C. (Sean Charles)

    2003-01-01

    Epitaxial processes are deposition processes that produce crystalline films with nano-scale precision. Many compound semiconductor devices rely on epitaxy to produce high-quality crystalline films with a specified compositional ...

  10. Ferromagnetism in Mn-Implanted Epitaxially Grown Ge on Si(100)

    E-Print Network [OSTI]

    Guchhait, S.

    2011-01-01

    investigating their use for spintronic devices. Epitaxial (the point of view that if spintronic devices are going to be

  11. Means and method for vapor generation

    DOE Patents [OSTI]

    Carlson, Larry W. (Oswego, IL)

    1984-01-01

    A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid--starting as "feedwater" heating where no vapors are present, progressing to "nucleate" heating where vaporization begins and some vapors are present, and concluding with "film" heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10-30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.

  12. Nonlithographic epitaxial SnxGe1x dense nanowire arrays grown on Ge,,001...

    E-Print Network [OSTI]

    Atwater, Harry

    Nonlithographic epitaxial SnxGe1Àx dense nanowire arrays grown on Ge,,001... Regina Ragan-thick SnxGe1 x /Ge(001) epitaxial films with 0 x 0.085 by molecular-beam epitaxy. These films evolve during growth into a dense array of SnxGe1 x nanowires oriented along 001 , as confirmed by composition contrast

  13. Finite Element Method for Epitaxial Growth with Attachment-Detachment Kinetics

    E-Print Network [OSTI]

    Li, Bo

    growth of thin films. Epitaxial growth is a technology for growing single crystal thin filmsFinite Element Method for Epitaxial Growth with Attachment-Detachment Kinetics Eberhard B in epitaxial growth. Such problems consist of an adatom (adsorbed atom) diffusion equation on terraces

  14. Interfacial band alignment and structural properties of nanoscale TiO{sub 2} thin films for integration with epitaxial crystallographic oriented germanium

    SciTech Connect (OSTI)

    Jain, N.; Zhu, Y.; Hudait, M. K., E-mail: mantu.hudait@vt.edu [Advanced Devices and Sustainable Energy Laboratory (ADSEL), Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Varghese, R.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2014-01-14

    We have investigated the structural and band alignment properties of nanoscale titanium dioxide (TiO{sub 2}) thin films deposited on epitaxial crystallographic oriented Ge layers grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy. The TiO{sub 2} thin films deposited at low temperature by physical vapor deposition were found to be amorphous in nature, and high-resolution transmission electron microscopy confirmed a sharp heterointerface between the TiO{sub 2} thin film and the epitaxially grown Ge with no traceable interfacial layer. A comprehensive assessment on the effect of substrate orientation on the band alignment at the TiO{sub 2}/Ge heterointerface is presented by utilizing x-ray photoelectron spectroscopy and spectroscopic ellipsometry. A band-gap of 3.33?±?0.02?eV was determined for the amorphous TiO{sub 2} thin film from the Tauc plot. Irrespective of the crystallographic orientation of the epitaxial Ge layer, a sufficient valence band-offset of greater than 2?eV was obtained at the TiO{sub 2}/Ge heterointerface while the corresponding conduction band-offsets for the aforementioned TiO{sub 2}/Ge system were found to be smaller than 1?eV. A comparative assessment on the effect of Ge substrate orientation revealed a valence band-offset relation of ?E{sub V}(100)?>??E{sub V}(111)?>??E{sub V}(110) and a conduction band-offset relation of ?E{sub C}(110) >??E{sub C}(111)?>??E{sub C}(100). These band-offset parameters are of critical importance and will provide key insight for the design and performance analysis of TiO{sub 2} for potential high-? dielectric integration and for future metal-insulator-semiconductor contact applications with next generation of Ge based metal-oxide field-effect transistors.

  15. Chemical vapor deposition coating for micromachines

    SciTech Connect (OSTI)

    MANI,SEETHAMBAL S.; FLEMING,JAMES G.; SNIEGOWSKI,JEFFRY J.; DE BOER,MAARTEN P.; IRWIN,LAWRENCE W.; WALRAVEN,JEREMY A.; TANNER,DANELLE M.; DUGGER,MICHAEL T.

    2000-04-21

    Two major problems associated with Si-based MEMS devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, the authors will present a process used to selectively coat MEMS devices with tungsten using a CVD (Chemical Vapor Deposition) process. The selective W deposition process results in a very conformal coating and can potentially solve both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through silicon reduction of WF{sub 6}, which results in a self-limiting reaction. The selective deposition of W only on polysilicon surfaces prevents electrical shorts. Further, the self-limiting nature of this selective W deposition process ensures the consistency necessary for process control. Selective tungsten is deposited after the removal of the sacrificial oxides to minimize process integration problems. This tungsten coating adheres well and is hard and conducting, requirements for device performance. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release stuck parts that are contacted over small areas such as dimples. Results from tungsten deposition on MEMS structures with dimples will be presented. The effect of wet and vapor phase cleanings prior to the deposition will be discussed along with other process details. The W coating improved wear by orders of magnitude compared to uncoated parts. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable.

  16. Temperature dependence of thermal conductivity of AlxGa1-xN thin films measured by the differential 3 technique

    E-Print Network [OSTI]

    Engineering, University of California­Riverside, Riverside, California 92521 (Received 2 July 2004; accepted conductivity of AlxGa1-xN thin films (x=0 and 0.4) grown by the hydride vapor phase epitaxy. ThermalN thin films (x=0 and 0.4) grown by the hydride vapor phase epitaxy (HVPE). The accurate values

  17. 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim p s scurrent topics in solid state physics

    E-Print Network [OSTI]

    Anderson, Timothy J.

    , Young Seok Kim, Olga Kryliouk* , and Tim Anderson Department of Chemical Engineering, University successfully reported; GaN NR growth by typical hydride vapor phase epitaxy (HVPE) [15], InN NR growth by hydride metal organic vapor phase epitaxy (H-MOVPE) from our efforts [9, 16], and AlN NR growth

  18. J. Cao, R. G. Broeke, N. K. Fontaine, C. Ji, Y. Du, N. Chubun, K. Aihara, Anh-Vu Pham, F. Olsson, S. Lourdudoss, and S. J. B. Yoo

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    -Vu Pham, and S. J. B. Yoo are with the Department of Electrical and Computer Engineering, University etching and planarizing Hydride-Vapor-Phase-Epitaxy lateral regrowth to realize buried hetero, fabricated by employing hydride vapor-phase epitaxy (HVPE) [9] facilitates monolithic integration

  19. Process for recovering organic vapors from air

    DOE Patents [OSTI]

    Baker, Richard W. (Mountain View, CA)

    1985-01-01

    A process for recovering and concentrating organic vapor from a feed stream of air having an organic vapor content of no more than 20,000 ppm by volume. A thin semipermeable membrane is provided which has a feed side and a permeate side, a selectivity for organic vapor over air of at least 50, as measured by the ratio of organic vapor permeability to nitrogen permeability, and a permeability of organic vapor of at least 3.times.10.sup.-7 cm.sup.3 (STP) cm/cm.sup.2 sec.cm Hg. The feed stream is passed across the feed side of the thin semipermeable membrane while providing a pressure on the permeate side which is lower than the feed side by creating a partial vacuum on the permeate side so that organic vapor passes preferentially through the membrane to form an organic vapor depleted air stream on the feed side and an organic vapor enriched stream on the permeate side. The organic vapor which has passed through the membrane is compressed and condensed to recover the vapor as a liquid.

  20. Vapor Barriers or Vapor Diffusion Retarders | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment of EnergyResearchers at theAugust 1, 2013theEnergyThe1984 StartVapor

  1. Effect of higher water vapor content on TBC performance

    SciTech Connect (OSTI)

    Pint, Bruce A; Haynes, James A

    2012-01-01

    Coal gasification, or IGCC (integrated gasification combined cycle), is one pathway toward cleaner use of coal for power generation with lower emissions. However, when coal-derived synthesis gas (i.e., syngas) is burned in turbines designed for natural gas, turbine manufacturers recommend 'derating,' or lowering the maximum temperature, which lowers the efficiency of the turbine, making electricity from IGCC more expensive. One possible reason for the derating is the higher water vapor contents in the exhaust gas. Water vapor has a detrimental effect on many oxidation-resistant high-temperature materials. In a turbine hot section, Ni-base superalloys are coated with a thermal barrier coating (TBC) allowing the gas temperature to be higher than the superalloy solidus temperature. TBCs have a low thermal conductivity ceramic top coating (typically Y{sub 2}O{sub 3}-stabilized ZrO{sub 2}, or YSZ) and an oxidation-resistant metallic bond coating. For land-based gas turbines, the industry standard is air plasma sprayed (APS) YSZ and high velocity oxygen fuel (HVOF) sprayed NiCoCrAlY bond coatings. To investigate the role of higher water vapor content on TBC performance and possible mitigation strategies, furnace cycling experiments were conducted in dry O{sub 2} and air with 10% (typical with natural gas or jet fuel) or 50 vol% water vapor. Cycle frequency and temperature were accelerated to one hour at 1100 C (with 10 minute cooling to {approx}30 C between each thermal cycle) to induce early failures in coatings that are expected to operate for several years with a metal temperature of {approx}900 C. Coupons (16 mm diameter x 2 mm thick) of commercial second-generation single crystal superalloy CMSX4 were HVOF coated on both sides with {approx}125 {micro}m of Ni-22wt%Co-17Cr-12Al either with 0.7Y or 0.7Y-0.3Hf-0.4Si. One side was then coated with 190-240 {micro}m of APS YSZ. Coatings were cycled until the YSZ top coating spalled. Figure 2 shows the results of the initial phase of experiments. Compared to dry O{sub 2}, the addition of 10% water vapor decreased the lifetime of MCrAlY by {approx}30% for the conventional CMSX4 substrates. Higher average lifetimes were observed with Hf in the bond coating, but a similar decrease in lifetime was observed when water vapor was added. The addition of Y and La to the superalloy substrate did not change the YSZ lifetime with 10% water vapor. However, increasing water vapor content from 10 to 50% did not further decrease the lifetime of either bond coating with the doped superalloy substrate. Thus, these results suggest that higher water vapor contents cannot explain the derating of syngas-fired turbines, and other factors such as sulfur and ash from imperfect syngas cleanup (or upset conditions) need to be explored. Researchers continue to study effects of water vapor on thermally grown alumina scale adhesion and growth rate, and are looking for bond coating compositions more resistant to oxidation in the presence of water vapor.

  2. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    E-Print Network [OSTI]

    Rivera, Jose Luis; Guerra-Gonzalez, Roberto

    2015-01-01

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect ...

  3. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    SciTech Connect (OSTI)

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.

    2009-11-25

    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline 9.0.2.3 (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

  4. Epitaxial growth of AlN films via plasma-assisted atomic layer epitaxy

    SciTech Connect (OSTI)

    Nepal, N.; Qadri, S. B.; Hite, J. K.; Mahadik, N. A.; Mastro, M. A.; Eddy, C. R. Jr.

    2013-08-19

    Thin AlN layers were grown at 200–650 °C by plasma assisted atomic layer epitaxy (PA-ALE) simultaneously on Si(111), sapphire (1120), and GaN/sapphire substrates. The AlN growth on Si(111) is self-limited for trimethyaluminum (TMA) pulse of length > 0.04 s, using a 10 s purge. However, the AlN nucleation on GaN/sapphire is non-uniform and has a bimodal island size distribution for TMA pulse of ?0.03 s. The growth rate (GR) remains almost constant for T{sub g} between 300 and 400 °C indicating ALE mode at those temperatures. The GR is increased by 20% at T{sub g} = 500 °C. Spectroscopic ellipsometry (SE) measurement shows that the ALE AlN layers grown at T{sub g} ? 400 °C have no clear band edge related features, however, the theoretically estimated band gap of 6.2 eV was measured for AlN grown at T{sub g} ? 500 °C. X-ray diffraction measurements on 37 nm thick AlN films grown at optimized growth conditions (T{sub g} = 500 °C, 10 s purge, 0.06 s TMA pulse) reveal that the ALE AlN on GaN/sapphire is (0002) oriented with rocking curve full width at the half maximum (FWHM) of 670 arc sec. Epitaxial growth of crystalline AlN layers by PA-ALE at low temperatures broadens application of the material in the technologies that require large area conformal growth at low temperatures with thickness control at the atomic scale.

  5. Control of flow through a vapor generator

    DOE Patents [OSTI]

    Radcliff, Thomas D.

    2005-11-08

    In a Rankine cycle system wherein a vapor generator receives heat from exhaust gases, provision is made to avoid overheating of the refrigerant during ORC system shut down while at the same time preventing condensation of those gases within the vapor generator when its temperature drops below a threshold temperature by diverting the flow of hot gases to ambient and to thereby draw ambient air through the vapor generator in the process. In one embodiment, a bistable ejector is adjustable between one position, in which the hot gases flow through the vapor generator, to another position wherein the gases are diverted away from the vapor generator. Another embodiment provides for a fixed valve ejector with a bias towards discharging to ambient, but with a fan on the downstream side of said vapor generator for overcoming this bias.

  6. Mercury Vapor | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsource HistoryScenariosMarysville MtMedical Area Total Egy PltMercuriusVapor Jump to:

  7. Coupling apparatus for a metal vapor laser

    DOE Patents [OSTI]

    Ball, D.G.; Miller, J.L.

    1993-02-23

    Coupling apparatus for a large bore metal vapor laser is disclosed. The coupling apparatus provides for coupling high voltage pulses (approximately 40 KV) to a metal vapor laser with a high repetition rate (approximately 5 KHz). The coupling apparatus utilizes existing thyratron circuits and provides suitable power input to a large bore metal vapor laser while maintaining satisfactory operating lifetimes for the existing thyratron circuits.

  8. Growth of epitaxial (Sr,Ba){sub n+1}Ru{sub n}O{sub 3n+1} films

    SciTech Connect (OSTI)

    Schlom, D.G.; Knapp, S.B.; Wozniak, S. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering] [and others

    1997-12-01

    We have grown epitaxial (Sr,Ba) (n+1)Ru(n)O(3n+1) films, n = 1, 2, and infinity, by pulsed laser deposition (PLD) and controlled their orientation by choosing appropriate substrates. The growth conditions yielding phase pure films have been mapped out. Resistivity versus temperature measurements show that both a and c axis films of Sr2RuO4 are metallic, but not superconducting. The latter is probably due to the presence of low-level impurities that are difficult to avoid given the target preparation process involved in growing these films by PLD.

  9. FLAMMABILITY CHARACTERISTICS OF COMBUSTIBLE GASES AND VAPORS

    Office of Scientific and Technical Information (OSTI)

    give a higher lower limit value than the completely vaporized sample. Conversely, the heavy fractions or residue give a smaller lower limit value. For this reason, there is...

  10. Multiperiod quantum-cascade nanoheterostructures: Epitaxy and diagnostics

    SciTech Connect (OSTI)

    Egorov, A. Yu. Brunkov, P. N.; Nikitina, E. V.; Pirogov, E. V.; Sobolev, M. S.; Lazarenko, A. A.; Baidakova, M. V.; Kirilenko, D. A.; Konnikov, S. G.

    2014-12-15

    Advances in the production technology of multiperiod nanoheterostructures of quantum-cascade lasers with 60 cascades by molecular-beam epitaxy (MBE) on an industrial multiple-substrate MBE machine are discussed. The results obtained in studying the nanoheterostructures of quantum-cascade lasers by transmission electron microscopy, high-resolution X-ray diffraction analysis, and photoluminescence mapping are presented.

  11. Cantilever Epitaxy Process Wins R&D 100 Award

    Broader source: Energy.gov [DOE]

    Sandia National Laboratories received an R&D 100 Award from R&D Magazine for development of a new process for growing gallium nitride on an etched sapphire substrate. The process, called cantilever epitaxy, promises to make brighter and more efficient green, blue, and white LEDs.

  12. Composition profiling of GaAs/AlGaAs quantum dots grown by droplet epitaxy

    SciTech Connect (OSTI)

    Bocquel, J.; Koenraad, P. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Giddings, A. D.; Prosa, T. J.; Larson, D. J. [CAMECA Instruments, Inc., 5500 Nobel Drive, Madison, Wisconsin 53711 (United States); Mano, T. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2014-10-13

    Droplet epitaxy (DE) is a growth method which can create III-V quantum dots (QDs) whose optoelectronic properties can be accurately controlled through the crystallisation conditions. In this work, GaAs/AlGaAs DE-QDs have been analyzed with the complimentary techniques of cross-sectional scanning tunneling microscopy and atom probe tomography. Structural details and a quantitative chemical analysis of QDs of different sizes are obtained. Most QDs were found to be pure GaAs, while a small proportion exhibited high intermixing caused by a local etching process. Large QDs with a high aspect ratio were observed to have an Al-rich crown above the GaAs QD. This structure is attributed to differences in mobility of the cations during the capping phase of the DE growth.

  13. Near real time vapor detection and enhancement using aerosol adsorption

    DOE Patents [OSTI]

    Novick, V.J.; Johnson, S.A.

    1999-08-03

    A vapor sample detection method is described where the vapor sample contains vapor and ambient air and surrounding natural background particles. The vapor sample detection method includes the steps of generating a supply of aerosol that have a particular effective median particle size, mixing the aerosol with the vapor sample forming aerosol and adsorbed vapor suspended in an air stream, impacting the suspended aerosol and adsorbed vapor upon a reflecting element, alternatively directing infrared light to the impacted aerosol and adsorbed vapor, detecting and analyzing the alternatively directed infrared light in essentially real time using a spectrometer and a microcomputer and identifying the vapor sample. 13 figs.

  14. G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) Value-Added Product

    SciTech Connect (OSTI)

    Koontz, A; Cadeddu, M

    2012-12-05

    The G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) value-added product (VAP) computes precipitable water vapor using neural network techniques from data measured by the GVR. The GVR reports time-series measurements of brightness temperatures for four channels located at 183.3 ± 1, 3, 7, and 14 GHz.

  15. Low Frequency Acoustic Resonance Studies of the Liquid-Vapor Transition in Silica Aerogel

    E-Print Network [OSTI]

    Tobias Herman; John Beamish

    2005-06-30

    Fluid phase transitions in porous media are a powerful probe of the effect of confinement and disorder on phase transitions. Aerogel may provide a model system in which to study the effect of dilute impurities on a variety of phase transitions. In this paper we present a series of low frequency acoustic experiments on the effect of aerogel on the liquid-vapor phase transition. Acoustic resonators were used to study the liquid-vapor transition in two fluids (helium and neon) and in two different porosity aerogels (95% and 98%). While effective coexistence curves could be mapped out, the transition was sometimes difficult to pinpoint, leading to doubt as to whether this transition can be treated as an equilibrium macroscopic phase transition at all.

  16. Cosine (Cobalt Silicide Growth Through Nitrogen-Induced Epitaxy) Process For Epitaxial Cobalt Silicide Formation For High Performance Sha

    DOE Patents [OSTI]

    Lim, Chong Wee (Urbana, IL); Shin, Chan Soo (Daejeon, KR); Gall, Daniel (Troy, NY); Petrov, Ivan Georgiev (Champaign, IL); Greene, Joseph E. (Champaign, IL)

    2004-09-28

    A method for forming an epitaxial cobalt silicide layer on a MOS device includes sputter depositing cobalt in an ambient to form a first layer of cobalt suicide on a gate and source/drain regions of the MOS device. Subsequently, cobalt is sputter deposited again in an ambient of argon to increase the thickness of the cobalt silicide layer to a second thickness.

  17. Methods of preparing flexible photovoltaic devices using epitaxial liftoff, and preserving the integrity of growth substrates used in epitaxial growth

    DOE Patents [OSTI]

    Forrest, Stephen R; Zimmerman, Jeramy; Lee, Kyusang; Shiu, Kuen-Ting

    2013-02-19

    There is disclosed methods of making photosensitive devices, such as flexible photovoltaic (PV) devices, through the use of epitaxial liftoff. Also described herein are methods of preparing flexible PV devices comprising a structure having a growth substrate, wherein the selective etching of protective layers yields a smooth growth substrate that us suitable for reuse.

  18. Efficient Interlayer Relaxation and Transition of Excitons in Epitaxial and Non-epitaxial MoS2/WS2 Heterostructures

    SciTech Connect (OSTI)

    Yu, Yifei [North Carolina State University, Raleigh; Hu, Shi [North Carolina State University, Raleigh; Su, Liqin [University of North Carolina, Charlotte; Huang, Lujun [North Carolina State University, Raleigh; Liu, Yi [North Carolina State University, Raleigh; Jin, Zhenghe [North Carolina State University, Raleigh; Puretzky, Alexander A [ORNL; Geohegan, David B [ORNL; Kim, Ki Wook [North Carolina State University, Raleigh; Zhang, Yong [University of North Carolina, Charlotte; Cao, Linyou [North Carolina State University

    2014-01-01

    Semiconductor heterostructurs provide a powerful platform for the engineering of excitons. Here we report on the excitonic properties of two-dimensional (2D) heterostructures that consist of monolayer MoS2 and WS2 stacked epitaxially or non-epitaxially in the vertical direction. We find similarly efficient interlayer relaxation and transition of excitons in both the epitaxial and non-epitaxial heterostructures. This is manifested by a two orders of magnitude decrease in the photoluminescence and an extra absorption peak at low energy region of both heterostructures. The MoS2/WS2 heterostructures show weak interlayer coupling and essentially act as an atomic-scale heterojunction with the intrinsic band structures of the two monolayers largely preserved. They are particularly promising for the applications that request efficient dissociation of excitons and strong light absorption, including photovoltaics, solar fuels, photodetectors, and optical modulators. Our results also indicate that 2D heterostructures promise to provide capabilities to engineer excitons from the atomic level without concerns of interfacial imperfection.

  19. LNG fire and vapor control system technologies

    SciTech Connect (OSTI)

    Konzek, G.J.; Yasutake, K.M.; Franklin, A.L.

    1982-06-01

    This report provides a review of fire and vapor control practices used in the liquefied natural gas (LNG) industry. Specific objectives of this effort were to summarize the state-of-the-art of LNG fire and vapor control; define representative LNG facilities and their associated fire and vapor control systems; and develop an approach for a quantitative effectiveness evaluation of LNG fire and vapor control systems. In this report a brief summary of LNG physical properties is given. This is followed by a discussion of basic fire and vapor control design philosophy and detailed reviews of fire and vapor control practices. The operating characteristics and typical applications and application limitations of leak detectors, fire detectors, dikes, coatings, closed circuit television, communication systems, dry chemicals, water, high expansion foam, carbon dioxide and halogenated hydrocarbons are described. Summary descriptions of a representative LNG peakshaving facility and import terminal are included in this report together with typical fire and vapor control systems and their locations in these types of facilities. This state-of-the-art review identifies large differences in the application of fire and vapor control systems throughout the LNG industry.

  20. Environmental Chemistry at Vapor/Water Interfaces

    E-Print Network [OSTI]

    Environmental Chemistry at Vapor/Water Interfaces: Insights from Vibrational Sum Frequency for manyyearsowingtoitscomplexityandimportanceindescribingawiderange of physical phenomena. The vapor/water interface is particularly interesting from an environmental for these systems is highlighted. A future perspective toward the application of VSFG to the study of environmental

  1. Quantitative organic vapor-particle sampler

    DOE Patents [OSTI]

    Gundel, Lara (Berkeley, CA); Daisey, Joan M. (Walnut Creek, CA); Stevens, Robert K. (Cary, NC)

    1998-01-01

    A quantitative organic vapor-particle sampler for sampling semi-volatile organic gases and particulate components. A semi-volatile organic reversible gas sorbent macroreticular resin agglomerates of randomly packed microspheres with the continuous porous structure of particles ranging in size between 0.05-10 .mu.m for use in an integrated diffusion vapor-particle sampler.

  2. Metallic 1T phase source/drain electrodes for field effect transistors...

    Office of Scientific and Technical Information (OSTI)

    PHASE TRANSFORMATIONS; TRANSITION ELEMENTS; TWO-DIMENSIONAL CALCULATIONS; VAPOR DEPOSITED COATINGS Word Cloud More Like This Full Text Journal Articles DOI: 10.10631.4896077...

  3. Atomic vapor laser isotope separation

    SciTech Connect (OSTI)

    Stern, R.C.; Paisner, J.A.

    1985-11-08

    Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements.

  4. Organic lateral heterojunction devices for vapor-phase chemical detection

    E-Print Network [OSTI]

    Ho, John C., 1980-

    2009-01-01

    As the U.S. is engaged in battle overseas, there is an urgent need for the development of sensors for early warning and protection of military forces against potential attacks. On the battlefields, improvised explosive ...

  5. MODELLING AND SIMULATION OF LIQUID-VAPOR PHASE TRANSITION

    E-Print Network [OSTI]

    Faccanoni, Gloria

    and Steam (secondary loop) Water (cooling loop) Pump Steam Generator Turbine Generator Cooling Tower Water pressurized (primary loop) Water and Steam (secondary loop) Water (cooling loop) Pump Steam Generator Turbine Generator Cooling Tower Condenser Cooling Water Pump Reactor Core Reactor Vessel Control

  6. Propane-induced biodegradation of vapor phase trichloroethylene...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Journal Article Resource Relation: Journal Name: Biotechnology and Bioengineering; Journal Volume: 46; Journal Issue: 4; Other Information: PBD: 20 May 1995 Country...

  7. Mechanistic aspects of vapor phase lubrication of silicon. (Conference) |

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport) | SciTechelement methodby hybrid-compoundSciTech Connect

  8. Propane-induced biodegradation of vapor phase trichloroethylene (Journal

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2)Article)SciTechon MPAS LandArticle) | SciTech

  9. Glenwood Springs Vapor Caves Pool & Spa Low Temperature Geothermal...

    Open Energy Info (EERE)

    Vapor Caves Pool & Spa Low Temperature Geothermal Facility Jump to: navigation, search Name Glenwood Springs Vapor Caves Pool & Spa Low Temperature Geothermal Facility Facility...

  10. After More Than 20 Years Operating, Hanford's Soil Vapor Extraction...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    After More Than 20 Years Operating, Hanford's Soil Vapor Extraction Project Nears Completion After More Than 20 Years Operating, Hanford's Soil Vapor Extraction Project Nears...

  11. VAPOR PRESSURES OF THE RUBIDIUM FLUORIDE-ZIRCONIUM FLUORIDE AND...

    Office of Scientific and Technical Information (OSTI)

    VAPOR PRESSURES OF THE RUBIDIUM FLUORIDE-ZIRCONIUM FLUORIDE AND LITHIUM FLUORIDE-ZIRCONIUM FLUORIDE SYSTEMS Citation Details In-Document Search Title: VAPOR PRESSURES OF THE...

  12. Growth Inhibition to Enhance Conformal Coverage in Thin Film Chemical Vapor Deposition

    E-Print Network [OSTI]

    Girolami, Gregory S.

    Technology Roadmap for Semiconductors predicts that it will be necessary to replace PVD with chemical vapor@scs.uiuc.edu; abelson@illinois.edu Many important technological applications depend crucially on the ability to deposit in a feature of given AR depends on the reactive sticking probability ( ) of the gas phase precursor

  13. Vapor-liquid equilibria and densities for the system butane + hexacontane

    SciTech Connect (OSTI)

    Nieuwoudt, I.

    1996-09-01

    Liquid and vapor phase compositions and densities have been measured with a variable volume cell for the binary system butane + hexacontane (n-C{sub 60}H{sub 122}). Data sets at 433.15 K, 438.15 K, and 453.15 K are presented and include measurements in the mixture critical region.

  14. Biochemical Engineering Journal 36 (2007) 250261 Dynamic simulation of benzene vapor treatment by a

    E-Print Network [OSTI]

    Daugulis, Andrew J.

    2007-01-01

    Biochemical Engineering Journal 36 (2007) 250­261 Dynamic simulation of benzene vapor treatment for the treatment of benzene waste gases by Achromobacter xylosoxidans Y234 with n-hexadecane as an immiscible, organic phase. Model calibration was performed to account for observed enhancements of benzene

  15. The Vapor Deposition and Oxidation of Platinum-and Yttria-Stabilized Zirconia Multilayers

    E-Print Network [OSTI]

    Wadley, Haydn

    The Vapor Deposition and Oxidation of Platinum- and Yttria-Stabilized Zirconia Multilayers Zhuo Yu system consisting of platinum- and yttria-stabilized zirconia (YSZ) multilayers. Coatings containing one on the bond coat surface with no intermediate metastable oxide precursor phase.9 Yttria-stabilized zirconia

  16. Structural perturbations of epitaxial ?-(Fe1-xVx)2O3 thin films driven by excess oxygen near the surface

    SciTech Connect (OSTI)

    Chamberlin, Sara E.; Kaspar, Tiffany C.; Bowden, Mark E.; Shutthanandan, V.; Kabius, Bernd C.; Heald, Steve M.; Keavney, David; Chambers, Scott A.

    2014-12-21

    We examine the structure and composition of phase-pure epitaxial ?-(Fe1-xVx)2O3 thin films deposited on ?-Al2O3(0001) substrates by oxygen-plasma-assisted molecular beam epitaxy for 0 ? x ? ~0.5. The films crystallize in the corundum lattice, with vanadium substituting for iron throughout. Vanadium cations exhibit the expected 3+ charge state in the bulk, but exhibit higher valences nearer to the surface, most likely because of excess oxygen in interstitial sites near the surface. The extent of vanadium oxidation beyond the 3+ state is inversely proportional to x. The gradation of vanadium valence with depth may have an impact on local bonding geometries, and could be highly significant in this material’s efficiency as a photocatalyst.

  17. Bismuth nano-droplets for group-V based molecular-beam droplet epitaxy

    SciTech Connect (OSTI)

    Li, C.; Zeng, Z. Q.; Hirono, Y.; Morgan, T. A.; Hu, X.; Salamo, G. J.; Fan, D. S.; Wu, J.; Yu, S. Q.; Wang, Zh. M.

    2011-12-12

    Self-assembly of bismuth droplets at nanoscale on GaAs(100) surface using molecular beam epitaxy was demonstrated. Fine control of density and size was achieved by varying growth temperature and total bismuth deposition. Droplet density was tuned by roughly 3 orders of magnitude, and the density-temperature dependence was found to be consistent with classical nucleation theory. These results may extend the flexibility of droplet epitaxy by serving as templates for group V based droplet epitaxy, which is in contrast to conventional group III based droplet epitaxy and may encourage nanostructure formation of bismuth-containing materials.

  18. Effects of lattice distortion on the physical properties and surface morphology of magnetoresistive perovskite epitaxial films

    E-Print Network [OSTI]

    Yeh, Nai-Chang

    perovskite epitaxial films N.-C. Yeh, C.-C. Fu, and J. Y. T. Wei Department of Physics, California Institute

  19. Process for depositing an oxide epitaxially onto a silicon substrate and structures prepared with the process

    DOE Patents [OSTI]

    McKee, Rodney A. (Kingston, TN); Walker, Frederick J. (Oak Ridge, TN)

    1993-01-01

    A process and structure involving a silicon substrate utilizes an ultra high vacuum and molecular beam epitaxy (MBE) methods to grow an epitaxial oxide film upon a surface of the substrate. As the film is grown, the lattice of the compound formed at the silicon interface becomes stabilized, and a base layer comprised of an oxide having a sodium chloride-type lattice structure grows epitaxially upon the compound so as to cover the substrate surface. A perovskite may then be grown epitaxially upon the base layer to render a product which incorporates silicon, with its electronic capabilities, with a perovskite having technologically-significant properties of its own.

  20. Ferromagnetism in Mn-Implanted Epitaxially Grown Ge on Si(100)

    E-Print Network [OSTI]

    Guchhait, S.

    2011-01-01

    investigating their use for spintronic devices. Epitaxial (the point of view that if spintronic devices are going to benew technologies, including spintronics, current-induced

  1. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    SciTech Connect (OSTI)

    Goyal, Amit

    2012-07-24

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  2. Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom

    DOE Patents [OSTI]

    Goyal, Amit

    2013-07-09

    A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

  3. Recovering hydrocarbons from hydrocarbon-containing vapors

    DOE Patents [OSTI]

    Mirza, Zia I. (La Verne, CA); Knell, Everett W. (Los Alamitos, CA); Winter, Bruce L. (Danville, CA)

    1980-09-30

    Values are recovered from a hydrocarbon-containing vapor by contacting the vapor with quench liquid consisting essentially of hydrocarbons to form a condensate and a vapor residue, the condensate and quench fluid forming a combined liquid stream. The combined liquid stream is mixed with a viscosity-lowering liquid to form a mixed liquid having a viscosity lower than the viscosity of the combined liquid stream to permit easy handling of the combined liquid stream. The quench liquid is a cooled portion of the mixed liquid. Viscosity-lowering liquid is separated from a portion of the mixed liquid and cycled to form additional mixed liquid.

  4. Epitaxial growth of three-dimensionally architectured optoelectronic devices

    SciTech Connect (OSTI)

    Nelson, Erik C.; Dias, Neville L.; Bassett, Kevin P.; Dunham, Simon N.; Verma, Varun; Miyake, Masao; Wiltzius, Pierre; Rogers, John A.; Coleman, James J.; Li, Xiuling; Braun, Paul V.

    2011-07-24

    Optoelectronic devices have long benefited from structuring in multiple dimensions on microscopic length scales. However, preserving crystal epitaxy, a general necessity for good optoelectronic properties, while imparting a complex three-dimensional structure remains a significant challenge. Three-dimensional (3D) photonic crystals are one class of materials where epitaxy of 3D structures would enable new functionalities. Many 3D photonic crystal devices have been proposed, including zero-threshold lasers, low-loss waveguides, high-efficiency light-emitting diodes (LEDs) and solar cells, but have generally not been realized because of material limitations. Exciting concepts in metamaterials, including negative refraction and cloaking, could be made practical using 3D structures that incorporate electrically pumped gain elements to balance the inherent optical loss of such devices. Here we demonstrate the 3D-template-directed epitaxy of group III–V materials, which enables formation of 3D structured optoelectronic devices. We illustrate the power of this technique by fabricating an electrically driven 3D photonic crystal LED.

  5. Ultrafast transient reflectance of epitaxial semiconducting perovskite thin films

    SciTech Connect (OSTI)

    Smolin, S. Y.; Guglietta, G. W.; Baxter, J. B. E-mail: smay@coe.drexel.edu; Scafetta, M. D.; May, S. J. E-mail: smay@coe.drexel.edu

    2014-07-14

    Ultrafast pump-probe transient reflectance (TR) spectroscopy was used to study carrier dynamics in an epitaxial perovskite oxide thin film of LaFeO{sub 3} (LFO) with a thickness of 40 unit cells (16?nm) grown by molecular beam epitaxy on (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (LSAT). TR spectroscopy shows two negative transients in reflectance with local maxima at ?2.5?eV and ?3.5?eV which correspond to two optical transitions in LFO as determined by ellipsometry. The kinetics at these transients were best fit with an exponential decay model with fast (5–40 ps), medium (?200 ps), and slow (??3?ns) components that we attribute mainly to recombination of photoexcited carriers. Moreover, these reflectance transients did not completely decay within the observable time window, indicating that ?10% of photoexcited carriers exist for at least 3?ns. This work illustrates that TR spectroscopy can be performed on thin (<20?nm) epitaxial oxide films to provide a quantitative understanding of recombination lifetimes, which are important parameters for the potential utilization of perovskite films in photovoltaic and photocatalytic applications.

  6. Phase appearance or disappearance in two-phase flows

    E-Print Network [OSTI]

    Boyer, Edmond

    safety studies. In nuclear reactors, the appearance of vapor around the fuel rods interferes-phase flows. Such models have crucial importance in many industrial areas such as nuclear power plant safety in a large variety of industrial or natural systems involving boiling or condensing fluids, reacting flows

  7. Au impact on GaAs epitaxial growth on GaAs (111){sub B} substrates in molecular beam epitaxy

    SciTech Connect (OSTI)

    Liao, Zhi-Ming; Chen, Zhi-Gang; Xu, Hong-Yi; Guo, Ya-Nan; Sun, Wen; Zhang, Zhi; Yang, Lei; Lu, Zhen-Yu; Chen, Ping-Ping; Lu, Wei; Zou, Jin; Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland 4072

    2013-02-11

    GaAs growth behaviour under the presence of Au nanoparticles on GaAs {l_brace}111{r_brace}{sub B} substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {l_brace}113{r_brace}{sub B} faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.

  8. Research Updates: Epitaxial strain relaxation and associated interfacial reconstructions: The driving force for creating new structures with integrated functionality

    SciTech Connect (OSTI)

    Zhu, Yuanyuan; Zhang, Wenrui [Program of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States); Chen, Aiping [Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843 (United States); Zhou, Honghui; Narayan, Jagdish [Department of Materials Science and Engineering, NSF Center for Advanced Materials and Smart Structures, North Carolina State University, Raleigh, North Carolina 27695 (United States); MacManus-Driscoll, Judith L. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Jia, Quanxi [Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Wang, Haiyan, E-mail: wangh@ece.tamu.edu [Program of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States); Department of Electrical and Computer Engineering, Texas A and M University, College Station, Texas 77843 (United States)

    2013-11-01

    Here, we report detailed strain mapping analysis at heterointerfaces of a new multiferroic complex oxide Bi{sub 3}Fe{sub 2}Mn{sub 2}O{sub x}(BFMO322) supercell and related layered structures. The state-of-the-art aberration corrected scanning transmission electron microscopy (Cs-corrected STEM) and the modified geometric phase analysis (GPA) have been used to characterize the self-assembled transitional layers, misfit defects, and, in particular, the biaxial lattice strain distributions. We found that not only a sufficient lattice misfit is required through substrate selection and to be preserved in initial coherent epilayer growth, but also an appropriate interfacial reconstruction is crucial for triggering the growth of the new BFMO322 supercell structure. The observation of new transitional interfacial phases behaving like coherent film layers within the critical thickness challenges the conventional understanding in existing epitaxial growth model.

  9. Chemical vapor deposition of antimicrobial polymer coatings

    E-Print Network [OSTI]

    Martin, Tyler Philip, 1977-

    2007-01-01

    There is large and growing interest in making a wide variety of materials and surfaces antimicrobial. Initiated chemical vapor deposition (iCVD), a solventless low-temperature process, is used to form thin films of polymers ...

  10. Chemical vapor infiltration using microwave energy

    DOE Patents [OSTI]

    Devlin, David J. (Los Alamos, NM); Currier, Robert P. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Barbero, Robert S. (Santa Cruz, NM)

    1993-01-01

    A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

  11. Modeling of LNG Pool Spreading and Vaporization 

    E-Print Network [OSTI]

    Basha, Omar 1988-

    2012-11-20

    In this work, a source term model for estimating the rate of spreading and vaporization of LNG on land and sea is introduced. The model takes into account the composition changes of the boiling mixture, the varying thermodynamic properties due...

  12. An advanced vapor-compression desalination system 

    E-Print Network [OSTI]

    Lara Ruiz, Jorge Horacio Juan

    2006-04-12

    Currently, the two dominant desalination methods are reverse osmosis (RO) and multi-stage flash (MSF). RO requires large capital investment and maintenance, whereas MSF is too energy intensive. An innovative vapor-compression desalination system...

  13. Vapor Retarder Classification - Building America Top Innovation...

    Broader source: Energy.gov (indexed) [DOE]

    vapor retarder classification. Air-tight and well-insulated homes have little or no tolerance for drying if they get wet; moisture control is critical. This Top Innovation profile...

  14. Chemical vapor deposition of functionalized isobenzofuran polymers

    E-Print Network [OSTI]

    Olsson, Ylva Kristina

    2007-01-01

    This thesis develops a platform for deposition of polymer thin films that can be further tailored by chemical surface modification. First, we explore chemical vapor deposition of functionalized isobenzofuran films using ...

  15. Water vapor distribution in protoplanetary disks

    SciTech Connect (OSTI)

    Du, Fujun; Bergin, Edwin A.

    2014-09-01

    Water vapor has been detected in protoplanetary disks. In this work, we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Ly? photons, since the Ly? line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column density of warm water vapor can be as high as 10{sup 22} cm{sup –2}. A small amount of hot water vapor with temperature higher than ?300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.

  16. Optical monitor for water vapor concentration

    DOE Patents [OSTI]

    Kebabian, Paul (Acton, MA)

    1998-01-01

    A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

  17. Optical monitor for water vapor concentration

    DOE Patents [OSTI]

    Kebabian, P.

    1998-06-02

    A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma. 5 figs.

  18. M. Bahrami ENSC 461 (S 11) Gas Vapor Mixtures and HVAC 1 Gas Vapor Mixtures and HVAC

    E-Print Network [OSTI]

    Bahrami, Majid

    to the vapor pressure: Tdp = Tsat@ Pv Sling Psychrometer: a rotating set of thermometers one of which measuresM. Bahrami ENSC 461 (S 11) Gas Vapor Mixtures and HVAC 1 Gas Vapor Mixtures and HVAC Atmospheric air normally contains some water vapor (moisture). The dry-air contains no water. Although the amount

  19. Lattice-registered growth of GaSb on Si (211) with molecular beam epitaxy

    SciTech Connect (OSTI)

    Hosseini Vajargah, S.; Botton, G. A.; Ghanad-Tavakoli, S.; Preston, J. S.; Kleiman, R. N.

    2012-11-01

    A GaSb film was grown on a Si(211) substrate using molecular beam epitaxy indicating full lattice relaxation as well as full lattice registration and dislocation-free growth in the plane perpendicular to the [01 - 1]-direction. Heteroepitaxy of GaSb on a Si(211) substrate is dominated by numerous first order and multiple higher order micro-twins. The atomic-resolved structural study of GaSb films by high-angle annular dark-field scanning transmission electron microscopy reveals that slight tilt, along with twinning, favors the lattice registry to Si(211) substrates. Preferential bonding of impinging Ga and Sb atoms at the interface due to two distinctive bonding sites on the Si(211) surface enables growth that is sublattice-ordered and free of anti-phase boundaries. The role of the substrate orientation on the strain distribution of GaSb epilayers is further elucidated by investigating the local change in the lattice parameter using the geometric phase analysis method and hence effectiveness of the lattice tilting in reducing the interfacial strain was confirmed further.

  20. Epitaxial ternary nitride thin films prepared by a chemical solution method

    SciTech Connect (OSTI)

    Luo, Hongmei [Los Alamos National Laboratory; Feldmann, David M [Los Alamos National Laboratory; Wang, Haiyan [TEXAS A& M; Bi, Zhenxing [TEXAS A& M

    2008-01-01

    It is indispensable to use thin films for many technological applications. This is the first report of epitaxial growth of ternary nitride AMN2 films. Epitaxial tetragonal SrTiN2 films have been successfully prepared by a chemical solution approach, polymer-assisted deposition. The structural, electrical, and optical properties of the films are also investigated.

  1. Epitaxial Growth of Rhenium with Sputtering Seongshik Oh 1,3

    E-Print Network [OSTI]

    Martinis, John M.

    : Epitaxy, Rhenium, Sputtering 1. Introduction Epitaxial superconducting films of refractory metals also has a reasonably high superconducting critical temperature (Tc = 1.7 K) [3], which is compatible oxidation condition, Re has much weaker tendency for oxidation than do most other elemental superconductors

  2. Highly Anisotropic Dirac Cones in Epitaxial Graphene Modulated by an Island Superlattice S. Rusponi,1

    E-Print Network [OSTI]

    Brune, Harald

    generation electronic devices [2]. Freestanding graphene is a zero-gap semiconductor. Because most electronicHighly Anisotropic Dirac Cones in Epitaxial Graphene Modulated by an Island Superlattice S. Rusponi asymmetry in epitaxial graphene by using metal cluster superlattices self-assembled onto the moire´ pattern

  3. Epitaxial integration of perovskite-based multifunctional oxides on silicon q

    E-Print Network [OSTI]

    Eom, Chang Beom

    Epitaxial integration of perovskite-based multifunctional oxides on silicon q Seung-Hyub Baek Epitaxial heterostructures of perovskite-type oxides have attracted much attention due to their enormous and multiferroics have been demonstrated in perovskite oxides. The combination of cations within perovskite unit

  4. Epitaxial growth of lead zirconium titanate thin films on Ag buffered Si substrates using rf sputtering

    E-Print Network [OSTI]

    Laughlin, David E.

    Epitaxial growth of lead zirconium titanate thin films on Ag buffered Si substrates using rf 7 February 2007; accepted 25 March 2007; published online 23 April 2007 Epitaxial lead zirconium American Institute of Physics. DOI: 10.1063/1.2731515 The ferroelectric material lead zirconium titanate Pb

  5. Design and fabrication of photonic crystals in epitaxial free silicon for ultrathin solar cells

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Design and fabrication of photonic crystals in epitaxial free silicon for ultrathin solar cells photovoltaic solar cell. Optical simulations performed on a complete solar cell revealed that patterning to obtain ultrathin patterned solar cells. Keywords: Photonic crystals; Epitaxial crystalline silicon; Thin

  6. Exploring the Potential for High-Quality Epitaxial CdTe Solar Cells , Ana Kanevce2

    E-Print Network [OSTI]

    Sites, James R.

    Exploring the Potential for High-Quality Epitaxial CdTe Solar Cells Tao Song1 , Ana Kanevce2Te solar cell performance is limited by recombination at the grain boundaries, low carrier density (p is not strongly affected until b exceeds 0.4 eV. Index Terms -- device modeling, solar cells, epitaxial CdTe. I

  7. Hypothetical Thermodynamic Properties. Subcooled Vaporization Enthalpies and Vapor Pressures of Polyaromatic Hydrocarbons

    E-Print Network [OSTI]

    Chickos, James S.

    of a thermochemical cycle, and agreement is within the combined experimental uncertainties. Vapor pressures pressures. Vaporization enthalpies of crystalline materials are also quite useful. Combined with fusion combined with fusion enthalpies have been used to provide independent confirmation of the magnitude

  8. Performance assessment of the In-Well Vapor-Stripping System

    SciTech Connect (OSTI)

    Gilmore, T.J.; White, M.D.; Spane, F.A. Jr.

    1996-10-01

    In-well vapor stripping is a remediation technology designed to preferentially extract volatile organic compounds dissolved in groundwater by converting them to a vapor phase and then treating the vapor. This vapor-stripping system is distinctly different from the more traditional in situ air-sparging concept. In situ sparging takes place in the aquifer formation; in-well vapor stripping takes place within the well casing. The system was field demonstrated at Edwards Air Force Base, California; the first-time demonstration of this technology in the United States. Installation and testing of the system were completed in late 1995, and the demonstration was operated nearly continuously for 6 months (191 days) between January 16 and July 25, 1996. Postdemonstration hydrochemical sampling continued until September 1996. The demonstration was conducted by collaborating researchers from Pacific Northwest National Laboratory (a) and Stanford University as part of an interim cleanup action at the base. Edwards Air Force Base and its environmental subcontractor, Earth Technology Corporation, as well as EG&G Environmental, holders of the commercial rights to the technology, were also significant contributors to the demonstration.

  9. Distribution of bismuth atoms in epitaxial GaAsBi

    SciTech Connect (OSTI)

    Sales, David [Universidad de Cadiz, Spain; Guerreo, E. [Universidad de Cadiz, Spain; Rodrigo, J.F. [Universidad de Cadiz, Spain; Galindo, P.L. [Universidad de Cadiz, Spain; Yanez, A. [University of Cadiz, Spain; Shafi, M. [University of Nottingham, Nottingham UK; Khatab, A. [University of Nottingham, Nottingham UK; Mari, R.H. [University of Nottingham, Nottingham UK; Henini, M. [University of Nottingham, Nottingham UK; Novikov, S. [University of Nottingham, Nottingham UK; Chisholm, Matthew F [ORNL; Molina, S.I. [Universidad de Cadiz, Spain

    2011-01-01

    The distribution of Bi atoms in epitaxial GaAs{sub (1-x)}Bi{sub x} is analyzed through aberration-corrected Z-contrast images. The relation between the atomic number and the intensity of the images allows quantifying the distribution of Bi atoms in this material. A bidimensional map of Bi atoms is extracted showing areas where nanoclustering is possible and evidencing the location of Bi at As-substitutional positions in the lattice. The distribution of Bi atoms differs from a random spatial pattern of Bi atoms in the material.

  10. Epitaxial growth of high quality WO3 thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Leng, X.; Pereiro, J.; Strle, J.; Bollinger, A. T.; Bozovic, I.

    2015-09-09

    We have grown epitaxial WO3 films on various single-crystal substrates using radio-frequency (RF) magnetron sputtering. While pronounced surface roughness is observed in films grown on LaSrAlO4 substrates, films grown on YAlO3 substrates show atomically flat surfaces, as demonstrated by atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements. The crystalline structure has been confirmed to be monoclinic by symmetric and skew-symmetric XRD. The dependence of the growth modes and the surface morphology on the lattice mismatch is discussed.

  11. Micro and nanostructured surfaces for enhanced phase change heat transfer

    E-Print Network [OSTI]

    Chu, Kuang-Han, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    Two-phase microchannel heat sinks are of significant interest for thermal management applications, where the latent heat of vaporization offers an efficient method to dissipate large heat fluxes in a compact device. However, ...

  12. Gas phase 129Xe NMR imaging and spectroscopy

    E-Print Network [OSTI]

    Kaiser, Lana G.

    2010-01-01

    5 l l Dynamic NMR microscopy of gas phase Poiseuille flowmetal vapors and noble gases can be used to efficientlypolarize the nuclei ofthe noble-gas atoms. As a result, the

  13. Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n-Alkanes from C40 to C76 at T ) 298.15 K by

    E-Print Network [OSTI]

    Chickos, James S.

    Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n in combination with earlier work to evaluate the vaporization enthalpies and vapor pressures of these n-alkanes from T ) (298.15 to 540) K. The vapor pressure and vaporization enthalpy results obtained are compared

  14. Vapor Pressures and Vaporization Enthalpies of the n-Alkanes from C31 to C38 at T ) 298.15 K by Correlation Gas Chromatography

    E-Print Network [OSTI]

    Chickos, James S.

    Vapor Pressures and Vaporization Enthalpies of the n-Alkanes from C31 to C38 at T ) 298.15 K with other literature values to evaluate the vaporization enthalpies and vapor pressures of these n-alkanes from T ) 298.15 to 575 K. The vapor pressure and vaporization enthalpy results obtained are compared

  15. Vapor Pressures and Vaporization Enthalpies of the n-Alkanes from C21 to C30 at T ) 298.15 K by Correlation Gas Chromatography

    E-Print Network [OSTI]

    Chickos, James S.

    Vapor Pressures and Vaporization Enthalpies of the n-Alkanes from C21 to C30 at T ) 298.15 K pressures of these n-alkanes from T ) 298.15 to 575 K. The vapor pressure and vaporization enthalpy results-alkanes exhibit very low vapor pressures at ambient temperatures, vapor pressure measurement for most

  16. Graphene growth with giant domains using chemical vapor deposition

    E-Print Network [OSTI]

    Yong, Virginia; Hahn, H. Thomas

    2011-01-01

    N. Martensson, Controlling graphene corrugation on lattice-in patterned epitaxial graphene, Science, 2006, 312(5777), 92009, 4(6), 17 A. K. Geim, Graphene: Status and Prospects,

  17. Laboratory testing of the in-well vapor-stripping system

    SciTech Connect (OSTI)

    Gilmore, T.J.; Francois, O.

    1996-03-01

    The Volatile organic Compounds-Arid Integrated Demonstration (VOC-Arid ID) was implemented by the US Department of Energy`s (DOE`s) Office of Technology Development to develop and test new technologies for the remediation of organic chemicals in the subsurface. One of the technologies being tested under the VOC-Arid ID is the in-well vapor-stripping system. The in-well vapor-stripping concept was initially proposed by researchers at Stanford University and is currently under development through a collaboration between workers at Stanford University and DOE`s Pacific Northwest National Laboratory. The project to demonstrate the in-well vapor-stripping technology is divided into three phases: (1) conceptual model and computer simulation, (2) laboratory testing, and (3) field demonstration. This report provides the methods and results of the laboratory testing in which a full-scale replica was constructed and tested above ground in a test facility located at DOE`s Hanford Site, Washington. The system is a remediation technology designed to preferentially extract volatile organic compounds (VOCs) from contaminated groundwater by converting them to a vapor phase.

  18. Vapor-like liquid coexistence densities affect the extension of the critical point's influence zone

    E-Print Network [OSTI]

    Jose Luis Rivera; Homero Nicanor-Guzman; Roberto Guerra-Gonzalez

    2015-04-16

    The critical point affects the coexistence behavior of the vapor-liquid equilibrium densities. The length of the critical influence zone is under debate because for some properties, like shear viscosity, the extension is only a few degrees, while for others, such as the density order parameter, the critical influence zone range covers up to hundreds of degrees below the critical temperature. Here we show that for a simple molecular potential of ethane, the critical influence zone covers a wide zone of tens of degrees (below the critical temperature) down to a transition temperature, at which the apparent critical influence zone vanishes and the transition temperature can be predicted through a pressure analysis of the coexisting bulk liquid phase. The liquid phases within the apparent critical influence zone show low densities, making them behave internally like their corresponding vapor phases. Therefore, the experimentally observed wide extension of the critical influence zone is due to a vapor-like effect due to low bulk liquid phase densities.

  19. Method and Apparatus for Concentrating Vapors for Analysis

    DOE Patents [OSTI]

    Grate, Jay W. (West Richland, WA); Baldwin, David L. (Kennewick, WA); Anheier, Jr., Norman C. (Richland, WA)

    2008-10-07

    An apparatus and method are disclosed for pre-concentrating gaseous vapors for analysis. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable. Vapors sorbed and concentrated within the bed of the apparatus can be thermally desorbed achieving at least partial separation of vapor mixtures. The apparatus is suitable, e.g., for preconcentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than for direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications.

  20. Diode pumped alkali vapor fiber laser

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Beach, Raymond J. (Livermore, CA); Dawson, Jay W. (Livermore, CA); Krupke, William F. (Pleasanton, CA)

    2006-07-26

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  1. Diode pumped alkali vapor fiber laser

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Beach, Raymond J. (Livermore, CA); Dawson, Jay W. (Livermore, CA); Krupke, William F. (Pleasanton, CA)

    2007-10-23

    A method and apparatus is provided for producing near-diffraction-limited laser light, or amplifying near-diffraction-limited light, in diode pumped alkali vapor photonic-band-gap fiber lasers or amplifiers. Laser light is both substantially generated and propagated in an alkali gas instead of a solid, allowing the nonlinear and damage limitations of conventional solid core fibers to be circumvented. Alkali vapor is introduced into the center hole of a photonic-band-gap fiber, which can then be pumped with light from a pump laser and operated as an oscillator with a seed beam, or can be configured as an amplifier.

  2. Thermal electric vapor trap arrangement and method

    DOE Patents [OSTI]

    Alger, T.

    1988-03-15

    A technique for trapping vapor within a section of a tube is disclosed herein. This technique utilizes a conventional, readily providable thermal electric device having a hot side and a cold side and means for powering the device to accomplish this. The cold side of this device is positioned sufficiently close to a predetermined section of the tube and is made sufficiently cold so that any condensable vapor passing through the predetermined tube section is condensed and trapped, preferably within the predetermined tube section itself. 4 figs.

  3. Apparatus for externally controlled closed-loop feedback digital epitaxy

    DOE Patents [OSTI]

    Eres, Djula (Knoxville, TN); Sharp, Jeffrey W. (Knoxville, TN)

    1996-01-01

    A method and apparatus for digital epitaxy. The apparatus includes a pulsed gas delivery assembly that supplies gaseous material to a substrate to form an adsorption layer of the gaseous material on the substrate. Structure is provided for measuring the isothermal desorption spectrum of the growth surface to monitor the active sites which are available for adsorption. The vacuum chamber housing the substrate facilitates evacuation of the gaseous material from the area adjacent the substrate following exposure. In use, digital epitaxy is achieved by exposing a substrate to a pulse of gaseous material to form an adsorption layer of the material on the substrate. The active sites on the substrate are monitored during the formation of the adsorption layer to determine if all the active sites have been filled. Once the active sites have been filled on the growth surface of the substrate, the pulse of gaseous material is terminated. The unreacted portion of the gas pulse is evacuated by continuous pumping. Subsequently, a second pulse is applied when availability of active sites is determined by studying the isothermal desorption spectrum. These steps are repeated until a thin film of sufficient thickness is produced.

  4. Apparatus for externally controlled closed-loop feedback digital epitaxy

    DOE Patents [OSTI]

    Eres, D.; Sharp, J.W.

    1996-07-30

    A method and apparatus for digital epitaxy are disclosed. The apparatus includes a pulsed gas delivery assembly that supplies gaseous material to a substrate to form an adsorption layer of the gaseous material on the substrate. Structure is provided for measuring the isothermal desorption spectrum of the growth surface to monitor the active sites which are available for adsorption. The vacuum chamber housing the substrate facilitates evacuation of the gaseous material from the area adjacent the substrate following exposure. In use, digital epitaxy is achieved by exposing a substrate to a pulse of gaseous material to form an adsorption layer of the material on the substrate. The active sites on the substrate are monitored during the formation of the adsorption layer to determine if all the active sites have been filled. Once the active sites have been filled on the growth surface of the substrate, the pulse of gaseous material is terminated. The unreacted portion of the gas pulse is evacuated by continuous pumping. Subsequently, a second pulse is applied when availability of active sites is determined by studying the isothermal desorption spectrum. These steps are repeated until a thin film of sufficient thickness is produced. 5 figs.

  5. Advanced Organic Vapor Cycles for Improving Thermal Conversion Efficiency in Renewable Energy Systems

    E-Print Network [OSTI]

    Ho, Tony

    2012-01-01

    pressure and entropy, pressure and vapor quality, andfluid at the high pressure vapor turbine exit. In the nexthigh pressure and low pressure vapor turbines. The increase

  6. THE KINETICS OF LASER PULSE VAPORIZATION OF URANIUM DIOXIDE BY MASS SPECTROMETRY

    E-Print Network [OSTI]

    Tsai, Chuen-horng

    2012-01-01

    resulting low vapor pressure and low heat of vaporizationresulting low vapor pressure and low heat of vaporizationyields the partial vapor pressure and the composition in the

  7. Mapping strain modulated electronic structure perturbations in mixed phase bismuth ferrite thin films

    SciTech Connect (OSTI)

    Krishnan, P.S. Sanakara R.; Aguiar, Jeffery A.; Ramasse, Q. M.; Kepaptsoglou, D. M.; Liang, W. I.; Chu, Y. H.; Browning, Nigel D.; Munroe, Paul R.; Nagarajan, Valanoor

    2015-01-01

    Strain engineering of epitaxial ferroelectrics has emerged as a powerful method to tailor the electromechanical response of these materials, although the effect of strain at the atomic scale and the interplay between lattice displacements and electronic structure changes are not yet fully understood. Here, using a combination of scanning transmission electron microscopy (STEM) and density functional theory (DFT), we systematically probe the role of epitaxial strain in mixed phase bismuth ferrite thin films. Electron energy loss O K and Fe L2,3 edge spectra acquired across the rhombohedral (R)-tetragonal (T) phase boundary reveal progressive, and systematic changes, in electronic structure going from one phase to the other. The comparison of the acquired spectra, with theoretical simulations using DFT, suggests a breakage in the structural symmetry across the boundary due to the simultaneous presence of increasing epitaxial strain and off- axial symmetry in the T phase. This implies that the imposed epitaxial strain plays a significant role in not only changing the crystal-field geometry, but also the bonding environment surrounding the central iron cation at the interface thus providing new insights and a possible link to understand how the imposed strain could perturb magnetic ordering in the T phase BFO.

  8. Low Temperature Chemical Vapor Deposition Of Thin Film Magnets

    DOE Patents [OSTI]

    Miller, Joel S. (Salt Lake City, UT); Pokhodnya, Kostyantyn I. (Salt Lake City, UT)

    2003-12-09

    A thin-film magnet formed from a gas-phase reaction of tetracyanoetheylene (TCNE) OR (TCNQ), 7,7,8,8-tetracyano-P-quinodimethane, and a vanadium-containing compound such as vanadium hexcarbonyl (V(CO).sub.6) and bis(benzene)vanalium (V(C.sub.6 H.sub.6).sub.2) and a process of forming a magnetic thin film upon at least one substrate by chemical vapor deposition (CVD) at a process temperature not exceeding approximately 90.degree. C. and in the absence of a solvent. The magnetic thin film is particularly suitable for being disposed upon rigid or flexible substrates at temperatures in the range of 40.degree. C. and 70.degree. C. The present invention exhibits air-stable characteristics and qualities and is particularly suitable for providing being disposed upon a wide variety of substrates.

  9. Molecular beam epitaxial growth and characterization of Bi{sub 2}Se{sub 3}/II-VI semiconductor heterostructures

    SciTech Connect (OSTI)

    Chen, Zhiyi Zhao, Lukas; Krusin-Elbaum, Lia; Garcia, Thor Axtmann; Tamargo, Maria C.; Hernandez-Mainet, Luis C.; Deng, Haiming

    2014-12-15

    Surfaces of three-dimensional topological insulators (TIs) have been proposed to host quantum phases at the interfaces with other types of materials, provided that the topological properties of interfacial regions remain unperturbed. Here, we report on the molecular beam epitaxy growth of II-VI semiconductor–TI heterostructures using c-plane sapphire substrates. Our studies demonstrate that Zn{sub 0.49}Cd{sub 0.51}Se and Zn{sub 0.23}Cd{sub 0.25}Mg{sub 0.52}Se layers have improved quality relative to ZnSe. The structures exhibit a large relative upward shift of the TI bulk quantum levels when the TI layers are very thin (?6nm), consistent with quantum confinement imposed by the wide bandgap II-VI layers. Our transport measurements show that the characteristic topological signatures of the Bi{sub 2}Se{sub 3} layers are preserved.

  10. Advancing Explosives Detection Capabilities: Vapor Detection

    SciTech Connect (OSTI)

    Atkinson, David

    2012-10-15

    A new, PNNL-developed method provides direct, real-time detection of trace amounts of explosives such as RDX, PETN and C-4. The method selectively ionizes a sample before passing the sample through a mass spectrometer to detect explosive vapors. The method could be used at airports to improve aviation security.

  11. Chemical vapor deposition of mullite coatings

    DOE Patents [OSTI]

    Sarin, Vinod (Lexington, MA); Mulpuri, Rao (Boston, MA)

    1998-01-01

    This invention is directed to the creation of crystalline mullite coatings having uniform microstructure by chemical vapor deposition (CVD). The process comprises the steps of establishing a flow of reactants which will yield mullite in a CVD reactor, and depositing a crystalline coating from the reactant flow. The process will yield crystalline coatings which are dense and of uniform thickness.

  12. Advancing Explosives Detection Capabilities: Vapor Detection

    ScienceCinema (OSTI)

    Atkinson, David

    2014-07-24

    A new, PNNL-developed method provides direct, real-time detection of trace amounts of explosives such as RDX, PETN and C-4. The method selectively ionizes a sample before passing the sample through a mass spectrometer to detect explosive vapors. The method could be used at airports to improve aviation security.

  13. The Effect of vapor subcooling on film condensation of metals

    E-Print Network [OSTI]

    Fedorovich, Eugene D.

    1968-01-01

    This work presents an analysis of the interfacial "vapor-condensate" temperature distribution, which includes the effect of subcooling (supersaturation) in the vapor. Experimental data from previous investigators for ...

  14. Vapor intrusion modeling : limitations, improvements, and value of information analyses

    E-Print Network [OSTI]

    Friscia, Jessica M. (Jessica Marie)

    2014-01-01

    Vapor intrusion is the migration of volatile organic compounds (VOCs) from a subsurface source into the indoor air of an overlying building. Vapor intrusion models, including the Johnson and Ettinger (J&E) model, can be ...

  15. Type B Accident Investigation of the Acid Vapor Inhalation on...

    Energy Savers [EERE]

    of the Acid Vapor Inhalation on June 7, 2005, in TA-48, Building RC-1 Room 402 at the Los Alamos National Laboratory Type B Accident Investigation of the Acid Vapor Inhalation on...

  16. Moisture Durability of Vapor Permeable Insulating Sheathing (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-10-01

    In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor permeable insulation on retrofit walls with vapor permeable cavity insulation. Retrofit strategies are a key factor in reducing exterior building stock consumption.

  17. MULTIPLY STRIPPED ION GENERATION IN THE METAL VAPOR VACUUM ARC

    E-Print Network [OSTI]

    Brown, I.G.

    2010-01-01

    the metal vapor vacuum arc plasma discharge. A new kind offrom a metal vapor vacuum arc plasma has been used to obtaindrives the vacuum arc plasma is created. The fundamental

  18. A Multiscale Simulator for Low Pressure Chemical Vapor Deposition

    E-Print Network [OSTI]

    A Multiscale Simulator for Low Pressure Chemical Vapor Deposition Matthias K. Gobbert Institute-6206 ABSTRACT An integrated simulator for chemical vapor deposition is introduced. In addition to a reactor

  19. OPTIMIZATION OF INJECTION INTO VAPOR-DOMINATED GEOTHERMAL

    E-Print Network [OSTI]

    Stanford University

    OPTIMIZATION OF INJECTION INTO VAPOR-DOMINATED GEOTHERMAL RESERVOIRS CONSIDERING ADSORPTION governing the behavior of vapor- dominated geothermal reservoirs. These mechanisms affect both was to determine the most effective injection strategy once these two effects are considered. Geothermal reservoir

  20. Vapor Transport of a Volatile Solvent for a Multicomponent Aerosol Droplet

    E-Print Network [OSTI]

    James Q. Feng

    2015-07-19

    This work presents analytical formulas derived for evaluating vapor transport of a volatile solvent for an isolated multicomponent droplet in a quiescent environment, based on quasi-steady-state approximation. Among multiple solvent components, only one component is considered to be much more volatile than the rest such that other components are assumed to be nonvolatile remaining unchanged in the droplet during the process of (single-component) volatile solvent evaporation or condensation. For evaporating droplet, the droplet size often initially decreases following the familiar "d^2 law" at an accelerated rate. But toward the end, the rate of droplet size change diminishes due to the presence of nonvolatile cosolvent. Such an acceleration-deceleration reversal behavior is unique for evaporating multicomponent droplet, while the droplet of pure solvent has an accelerated rate of size change all the way through the end. This reversal behavior is also reflected in the droplet surface temperature evolution as "S-shaped" curves. However, a closer mathematical examination of conditions for acceleration-deceleration reversal indicates that the acceleration phase may disappear when the amount of nonvolatile cosolvent is relatively small and ambient vapor pressure is relatively high. Because the net effect of adding nonvolatile cosolvent is to reduce the mole fraction of the volatile solvent such that the saturation vapor pressure is lowered, vapor condensation onto the multicomponent droplet is predicted to occur when the ambient vapor pressure is subsaturated with respect to that for the pure volatile solvent. In this case, the droplet will grow asymptotically toward a finite size. But when the ambient vapor pressure becomes supersaturated with respect to that for the pure volatile solvent, the condensation growth of droplet can continue indefinitely without bound.

  1. Heat Recovery in Distillation by Mechanical Vapor Recompression 

    E-Print Network [OSTI]

    Becker, F. E.; Zakak, A. I.

    1986-01-01

    IN DISTILLATION BY MECHANICAL VAPOR RECOMPRESSION Frederick E. Becker and Alexandra I. Zakak Tecogen, Inc., A Subsidiary of Thermo Electron Corporation Waltham, Massachusetts ABSTRACT A significant reduction in distillation tower energy requirements can..., and then recompressing the low-pressure bottom vapors and injecting them directly into the column bottom. The choice of either scheme is a function of the physical properties of the vapors; i.e., the specific volume of the top or bottom vapors may dictate the most...

  2. Characterization of Instrumental Phase Stability

    E-Print Network [OSTI]

    D. Y. Kubo; T. R. Hunter; R. D. Christensen; P. I. Yamaguchi

    2007-04-17

    Atmospheric water vapor causes significant undesired phase fluctuations for the Submillimeter Array (SMA) interferometer, particularly in its highest frequency observing band of 690 GHz. One proposed solution to this atmospheric effect is to observe simultaneously at two separate frequency bands of 230 and 690 GHz. Although the phase fluctuations have a smaller magnitude at the lower frequency, they can be measured more accurately and on shorter timescales due to the greater sensitivity of the array to celestial point source calibrators at this frequency. In theory, we can measure the atmospheric phase fluctuations in the 230 GHz band, scale them appropriately with frequency, and apply them to the data in 690 band during the post-observation calibration process. The ultimate limit to this atmospheric phase calibration scheme will be set by the instrumental phase stability of the IF and LO systems. We describe the methodology and initial results of the phase stability characterization of the IF and LO systems.

  3. Modeling engine oil vaporization and transport of the oil vapor in the piston ring pack on internal combustion engines

    E-Print Network [OSTI]

    Cho, Yeunwoo, 1973-

    2004-01-01

    A model was developed to study engine oil vaporization and oil vapor transport in the piston ring pack of internal combustion engines. With the assumption that the multi-grade oil can be modeled as a compound of several ...

  4. Study of the effects of noisy data on the determination of the enthalpy of vaporization from a vapor pressure equation 

    E-Print Network [OSTI]

    Casserly, Thomas Bryan

    2013-02-22

    Chemical engineers use software tools everyday to aid them in solving complex problems. Software packages simulate virtually every aspect of a chemical process, including the use of source vapor pressure data to fit empirical constants of a vapor...

  5. THE KINETICS OF LASER PULSE VAPORIZATION OF URANIUM DIOXIDE BY MASS SPECTROMETRY

    E-Print Network [OSTI]

    Tsai, C-h.

    2010-01-01

    The results of the vapor pressure and the vapor compositionyielded the partial vapor pressure of each species and therecommer.ded limits of total vapor pressure This work fitted

  6. Growth of Ca{sub 2}MnO{sub 4} Ruddlesden-Popper structured thin films using combinatorial substrate epitaxy

    SciTech Connect (OSTI)

    Lacotte, M.; David, A.; Pravarthana, D.; Prellier, W.; Grygiel, C.; Rohrer, G. S.; Salvador, P. A.; Velazquez, M.; Kloe, R. de

    2014-12-28

    The local epitaxial growth of pulsed laser deposited Ca{sub 2}MnO{sub 4} films on polycrystalline spark plasma sintered Sr{sub 2}TiO{sub 4} substrates was investigated to determine phase formation and preferred epitaxial orientation relationships (ORs) for isostructural Ruddlesden-Popper (RP) heteroepitaxy, further developing the high-throughput synthetic approach called Combinatorial Substrate Epitaxy (CSE). Both grazing incidence X-ray diffraction and electron backscatter diffraction patterns of the film and substrate were indexable as single-phase RP-structured compounds. The optimal growth temperature (between 650?°C and 800?°C) was found to be 750?°C using the maximum value of the average image quality of the backscattered diffraction patterns. Films grew in a grain-over-grain pattern such that each Ca{sub 2}MnO{sub 4} grain had a single OR with the Sr{sub 2}TiO{sub 4} grain on which it grew. Three primary ORs described 47 out of 49 grain pairs that covered nearly all of RP orientation space. The first OR, found for 20 of the 49, was the expected RP unit-cell over RP unit-cell OR, expressed as [100][001]{sub film}||[100][001]{sub sub}. The other two ORs were essentially rotated from the first by 90°, with one (observed for 17 of 49 pairs) being rotated about the [100] and the other (observed for 10 of 49 pairs) being rotated about the [110] (and not exactly by 90°). These results indicate that only a small number of ORs are needed to describe isostructural RP heteroepitaxy and further demonstrate the potential of CSE in the design and growth of a wide range of complex functional oxides.

  7. Directed inorganic modification of bi-component polymer fibers by selective vapor reaction and atomic layer deposition

    E-Print Network [OSTI]

    Khan, Saad A.

    and atomic layer deposition Bo Gong, Joseph C. Spagnola, Sara A. Arvidson, Saad A. Khan, Gregory N. Parsons Accepted 8 August 2012 Available online 21 August 2012 Keywords: Atomic layer deposition Bi-controlled composition can be formed using vapor-phase atomic layer deposition (ALD) on bi-component polymer fibers

  8. Structure of Zirconium-Exchanged H-ZSM5 Prepared by Vapor Exchange of ZrCl4

    E-Print Network [OSTI]

    Iglesia, Enrique

    Structure of Zirconium-Exchanged H-ZSM5 Prepared by Vapor Exchange of ZrCl4 Howard S. Lacheen phase. Zirconium silicates (ZrxSi1-xO2) have been reported to form for several zeolite structures

  9. Half-Metallic Ferromagnetism and Structural Stability of Zincblende Phases of the Transition-Metal Chalcogenides

    E-Print Network [OSTI]

    Wikswo, John

    epitaxially in the form of films and layers thick enough for spintronic applications. DOI: 10.1103/Phys as a key ingre- dient in future high performance spintronic devices, be- cause they have only one-arsenide (B81) phases. However, spintronic devices require thick films or layers. Therefore, it is important

  10. 1/f noise in all-epitaxial metal-semiconductor diodes

    E-Print Network [OSTI]

    Young, Adam C; Zimmerman, J D; Brown, E R; Gossard, A C

    2006-01-01

    S. Kogan, Electronic Noise and Fluctuations in SolidsLETTERS 88, 073518 ?2006? 1/f noise in all-epitaxial metal-in the low-frequency noise performance by using MBE-grown

  11. Broadband electromagnetic response and ultrafast dynamics of few-layer epitaxial graphene

    E-Print Network [OSTI]

    Choi, Hyunyong

    2010-01-01

    of few-layer epitaxial graphene H. Choi, 1 F. Borondics, 2a con?r- mation of graphene’s unusual electrodynamics. ThisLett. 96, 256802 (2006). graphene THz/IR SiC FIG. 1: (Color

  12. Free-Standing Epitaxial Graphene Shriram Shivaraman,* Robert A. Barton, Xun Yu, Jonathan Alden,

    E-Print Network [OSTI]

    McEuen, Paul L.

    Free-Standing Epitaxial Graphene Shriram Shivaraman,* Robert A. Barton, Xun Yu, Jonathan Alden process is shown in Figure 1. Fabrication of the devices proceeded by evaporating 100 nm of gold

  13. Effective lifetimes exceeding 300 ?s in gettered p-type epitaxial kerfless silicon for photovoltaics

    E-Print Network [OSTI]

    Powell, D. M.

    We evaluate defect concentrations and investigate the lifetime potential of p-type single-crystal kerfless silicon produced via epitaxy for photovoltaics. In gettered material, low interstitial iron concentrations (as low ...

  14. Applied Materials Develops an Advanced Epitaxial Growth System to Bring Down LED Costs

    Broader source: Energy.gov [DOE]

    With the help of DOE funding, Applied Materials has developed an advanced epitaxial growth system for gallium nitride (GaN) LED devices that decreases operating costs, increases internal quantum efficiency, and improves binning yields.

  15. Strain controlled metal-insulator transition in epitaxial NdNiO{sub 3} thin films

    SciTech Connect (OSTI)

    Xiang, P.-H. Zhong, N.; Duan, C.-G.; Tang, X. D.; Hu, Z. G.; Yang, P. X.; Zhu, Z. Q.; Chu, J. H.

    2013-12-28

    We have fabricated epitaxial thin films of NdNiO{sub 3} (NNO) on various single crystal substrates. The transport properties of NNO films are very sensitive to substrate-controlled epitaxial strain. As the strain varies from tensile to compressive, the Mott metal-insulator transition of NNO films shifts to low temperatures. Under a larger compressive strain, the film on LaSrAlO{sub 4} substrate exhibits a practically metallic transport characteristic. We have found that the conductivities of NNO films at low temperatures follow Mott's variable range hopping mechanism rather than thermal activation model and the epitaxial strain has a strong effect on Mott's parameters of NNO films. These findings demonstrate that the electronic transport of NNO thin films can be tuned by the epitaxial strain for next-generation perovskite-based microelectronic devices.

  16. Epitaxial Ge/Il-V Heterostructures : MOCVD growth, characterization, and applications

    E-Print Network [OSTI]

    Bai, Yu, Ph.D. Massachusetts Institute of Technology

    2011-01-01

    Epitaxial Ge thin films are being investigated for many important roles in next generation microelectronics. Metal-oxide-semiconductor field effect transistors (MOSFETs) utilizing Ge channels have demonstrated dramatic ...

  17. Chemical beam epitaxy growth of III–V semiconductor nanowires

    SciTech Connect (OSTI)

    Mohummed Noori, Farah T. [University of Baghdad , College of science, Physics department , Jadiriya ,Baghdad (Iraq)

    2013-12-16

    Indium- Arsenide (InAs) nanowires were grown in a high vacuum chemical beam epitaxy (CBE) unit on InAs(111) wafers substrates at 425–454°C. Two types of nanogold were used as orientation catalyst, 40nm and 80nm. The measurements were performed using scanning electron microscopy showed that uniform nanowires. The nanowires orient vertically in the InAs nanowire scanning electron microscopy of an array 80nm diameter InAs nanowire with length is in the range 0.5–1 ?m and of an array 40nm diameter with length is in the range 0.3–0.7?m. The nanowire length with growth time shows that the linear increase of nanowires start to grow as soon as TMIn is available. The growth rate with temperature was studied.

  18. Electronic Cooling via Interlayer Coulomb Coupling in Multilayer Epitaxial Graphene

    E-Print Network [OSTI]

    Mihnev, Momchil T; Divin, Charles J; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A; MacDonald, Allan H; Norris, Theodore B

    2015-01-01

    In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron-phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier ...

  19. Advanced Membrane Systems: Recovering Wasteful and Hazardous Fuel Vapors at the Gasoline Tank

    Office of Energy Efficiency and Renewable Energy (EERE)

    Case study covering Compact Membrane Systems, Inc. and its membrane vapor processor that recovers fuel vapors from gasoline refueling.

  20. Greatly improved interfacial passivation of in-situ high ? dielectric deposition on freshly grown molecule beam epitaxy Ge epitaxial layer on Ge(100)

    SciTech Connect (OSTI)

    Chu, R. L. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liu, Y. C.; Lee, W. C.; Huang, M. L.; Kwo, J., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, T. D.; Hong, M., E-mail: raynien@phys.nthu.edu.tw, E-mail: mhong@phys.ntu.edu.tw [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Pi, T. W. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

    2014-05-19

    A high-quality high-?/Ge interface has been achieved by combining molecule beam epitaxy grown Ge epitaxial layer and in-situ deposited high ? dielectric. The employment of Ge epitaxial layer has sucessfully buried and/or removed the residue of unfavorable carbon and native oxides on the chemically cleaned and ultra-high vacuum annealed Ge(100) wafer surface, as studied using angle-resolved x-ray photoelectron spectroscopy. Moreover, the scanning tunneling microscopy analyses showed the significant improvements in Ge surface roughness from 3.5?Å to 1?Å with the epi-layer growth. Thus, chemically cleaner, atomically more ordered, and morphologically smoother Ge surfaces were obtained for the subsquent deposition of high ? dielectrics, comparing with those substrates without Ge epi-layer. The capacitance-voltage (C-V) characteristics and low extracted interfacial trap density (D{sub it}) reveal the improved high-?/Ge interface using the Ge epi-layer approach.

  1. Heat storage system utilizing phase change materials government rights

    DOE Patents [OSTI]

    Salyer, Ival O. (Dayton, OH)

    2000-09-12

    A thermal energy transport and storage system is provided which includes an evaporator containing a mixture of a first phase change material and a silica powder, and a condenser containing a second phase change material. The silica powder/PCM mixture absorbs heat energy from a source such as a solar collector such that the phase change material forms a vapor which is transported from the evaporator to the condenser, where the second phase change material melts and stores the heat energy, then releases the energy to an environmental space via a heat exchanger. The vapor is condensed to a liquid which is transported back to the evaporator. The system allows the repeated transfer of thermal energy using the heat of vaporization and condensation of the phase change material.

  2. Doping and electronic properties of GaAs grown by close-spaced vapor transport from powder sources for scalable III–V photovoltaics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ritenour, Andrew J.; Boucher, Jason W.; DeLancey, Robert; Greenaway, Ann L.; Aloni, Shaul; Boettcher, Shannon W.

    2014-09-01

    We report the use of a simple close-spaced vapor transport technique for the growth of high-quality epitaxial GaAs films using potentially inexpensive GaAs powders as precursors. The free carrier type and density (1016 to 1019 cm–3) of the films were adjusted by addition of Te or Zn powder to the GaAs source powder. We show using photoelectrochemical and electron beam-induced current analyses that the minority carrier diffusion lengths of the n- and p-GaAs films reached ~3 ?m and ~8 ?m, respectively. Hall mobilities approach those achieved for GaAs grown by metal–organic chemical vapor deposition, 1000–4200 cm2 V–1 s–1 for n-GaAsmore »and 50–240 cm V–1 s–1 for p-GaAs depending on doping level. We conclude that the electronic quality of GaAs grown by close-spaced vapor transport is similar to that of GaAs made using conventional techniques and is thus sufficient for high-performance photovoltaic applications.« less

  3. Doping and electronic properties of GaAs grown by close-spaced vapor transport from powder sources for scalable III–V photovoltaics

    SciTech Connect (OSTI)

    Ritenour, Andrew J.; Boucher, Jason W.; DeLancey, Robert; Greenaway, Ann L.; Aloni, Shaul; Boettcher, Shannon W.

    2014-09-01

    We report the use of a simple close-spaced vapor transport technique for the growth of high-quality epitaxial GaAs films using potentially inexpensive GaAs powders as precursors. The free carrier type and density (1016 to 1019 cm–3) of the films were adjusted by addition of Te or Zn powder to the GaAs source powder. We show using photoelectrochemical and electron beam-induced current analyses that the minority carrier diffusion lengths of the n- and p-GaAs films reached ~3 ?m and ~8 ?m, respectively. Hall mobilities approach those achieved for GaAs grown by metal–organic chemical vapor deposition, 1000–4200 cm2 V–1 s–1 for n-GaAs and 50–240 cm V–1 s–1 for p-GaAs depending on doping level. We conclude that the electronic quality of GaAs grown by close-spaced vapor transport is similar to that of GaAs made using conventional techniques and is thus sufficient for high-performance photovoltaic applications.

  4. Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n-Alkanes from C78 to C92 at T ) 298.15 K by

    E-Print Network [OSTI]

    Chickos, James S.

    Hypothetical Thermodynamic Properties: Vapor Pressures and Vaporization Enthalpies of the Even n and vapor pressures of the n-alkanes from T ) (298.15 to 540) K for heneicosane to dononacontane. The vapor pressure and vaporization enthalpy results obtained are compared with estimated data from Morgan's "PERT2

  5. Comparison of the crystalline structure, morphology, and magnetic properties of -phase Mn/Cu3Au,,100... ultrathin films by varying the growth temperature

    E-Print Network [OSTI]

    Lin, Minn-Tsong

    Comparison of the crystalline structure, morphology, and magnetic properties of -phase Mn/Cu3Au behaviors in the crystalline structure, morphology, and magnetism. RT-Mn films reveal apparent layer the last de- cade, the pure - and -phase Mn films are prepared by epitaxial growth on single-crystalline

  6. Copper vapor laser modular packaging assembly

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA); Ault, Earl R. (Dublin, CA); Moses, Edward I. (Castro Valley, CA)

    1992-01-01

    A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment.

  7. Copper vapor laser modular packaging assembly

    DOE Patents [OSTI]

    Alger, T.W.; Ault, E.R.; Moses, E.I.

    1992-12-01

    A modularized packaging arrangement for one or more copper vapor lasers and associated equipment is disclosed herein. This arrangement includes a single housing which contains the laser or lasers and all their associated equipment except power, water and neon, and means for bringing power, water, and neon which are necessary to the operation of the lasers into the container for use by the laser or lasers and their associated equipment. 2 figs.

  8. Apparatus and method for photochemical vapor deposition

    DOE Patents [OSTI]

    Jackson, Scott C. (Wilmington, DE); Rocheleau, Richard E. (Wilmington, DE)

    1987-03-31

    A photochemical vapor deposition apparatus includes a reactor housing having a window in one wall above a reaction chamber in the housing. A transparent curtain divides the reaction chamber into a reaction zone and a flush zone. At least one substrate is mounted in the reaction zone in light communication with the window so that ultraviolet radiation may penetrate through the window into the reaction zone. The window is kept clear by a gas flowing through the flush zone.

  9. Water vapor distribution in protoplanetary disks

    E-Print Network [OSTI]

    Du, Fujun

    2014-01-01

    Water vapor has been detected in protoplanetary disks. In this work we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Lyman alpha photons, since the Lyman alpha line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more ...

  10. High volume fuel vapor release valve

    SciTech Connect (OSTI)

    Gimby, D.R.

    1991-09-03

    This patent describes a fuel vapor release valve for use in a vehicle fuel system. It comprises a valve housing 10 placed in a specific longitudinal orientation, the valve housing 10 defining an interior cavity 22 having an inlet 20 for admitting fuel vapor and an outlet 14 for discharging such fuel vapor; a valve member 24 positioned in the cavity 22 for movement between an outlet 14 opening position and an outlet 14 closing position, the valve member 24 including a cap member 34 having a seat surface 36 for mating with the outlet 14 and an orifice 42 extending through the cap member 34 providing a passageway from the outlet 14 to the cavity 22, the orifice 42 extending through the cap member 34 providing a passageway from the outlet 14 to the cavity 22, the orifice 42 having a lesser radius than the outlet 14; the valve member 24 further including a plug member 30 engaged with the cap member 34 for movement between an orifice 42 opening position and an orifice 42 closing position; and, a valve housing tilt responsive means for moving the valve member 24 to an outlet 14 and orifice 42 closing position in response to tilting of the valve 10 about its longitudinal axis whereby, upon the return of the valve 10 to its specified longitudinal orientation, the plug member 30 first moves to an orifice 42 opening position and the cap member 34 subsequently moves to an outlet 14 opening position.

  11. Combined rankine and vapor compression cycles

    DOE Patents [OSTI]

    Radcliff, Thomas D.; Biederman, Bruce P.; Brasz, Joost J.

    2005-04-19

    An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor. In another embodiment, an organic rankine cycle system is applied to an internal combustion engine to cool the fluids thereof, and the turbo charged air is cooled first by the organic rankine cycle system and then by an air conditioner prior to passing into the intake of the engine.

  12. Spectral Encoding and Decoding of Monolithic InP OCDMA Encoder , R. G. Broeke

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    . Lourdudoss3 , and S. J. B. Yoo 1 1: Department of Electrical and Computer Engineering, University-CDMA encoder realized in an InP material system with planarized BH waveguides using Hydride Vapor Phase Epitaxy

  13. A Monolithic Ultra-compact InP O-CDMA Encoder with Planarization by HPVE Regrowth

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    Engineering, University of California, Davis, CA 95616, USA Email: yoo@ece.ucdavis.edu F. Olsson, SP with surface planarization by low-pressure Hydride-Vapor-Phase-Epitaxy regrowth. The chip consists of an AWG

  14. Optical Gain and Laser Characteristics of InGaN Quantum Wells on Ternary InGaN Substrates

    E-Print Network [OSTI]

    Gilchrist, James F.

    Member, IEEE Center for Photonics and Nanoelectronics, Department of Electrical and Computer Engineering] and hydride vapor phase epitaxy [39]. Recent works [40], [41] had shown the feasibility for accessing

  15. Manufacturing Cost Analysis Relevant to Single-and Dual-Junction Photovoltaic Cells Fabricated with III-Vs and III-Vs Grown on Czochralski Silicon (Presentation)

    SciTech Connect (OSTI)

    Woodhouse, M.; Goodrich, A.

    2014-05-01

    In this analysis we examine the current, mid-term, and long-term manufacturing costs for III-Vs deposited by traditional Metal Organic Vapor Phase Epitaxy (MOVPE).

  16. Synthesis of alloys with controlled phase structure

    DOE Patents [OSTI]

    Guthrie, Stephen Everett (Livermore, CA); Thomas, George John (Livermore, CA); Bauer, Walter (Livermore, CA); Yang, Nancy Yuan Chi (Lafayette, CA)

    1999-04-20

    A method for preparing controlled phase alloys useful for engineering and hydrogen storage applications. This novel method avoids melting the constituents by employing vapor transport, in a hydrogen atmosphere, of an active metal constituent, having a high vapor pressure at temperatures .apprxeq.300 C. and its subsequent condensation on and reaction with the other constituent (substrate) of an alloy thereby forming a controlled phase alloy and preferably a single phase alloy. It is preferred that the substrate material be a metal powder such that diffusion of the active metal constituent, preferably magnesium, and reaction therewith can be completed within a reasonable time and at temperatures .apprxeq.300 C. thereby avoiding undesirable effects such as sintering, local compositional inhomogeneities, segregation, and formation of unwanted second phases such as intermetallic compounds.

  17. Synthesis of alloys with controlled phase structure

    DOE Patents [OSTI]

    Guthrie, S.E.; Thomas, G.J.; Bauer, W.; Yang, N.Y.C.

    1999-04-20

    A method is described for preparing controlled phase alloys useful for engineering and hydrogen storage applications. This novel method avoids melting the constituents by employing vapor transport, in a hydrogen atmosphere, of an active metal constituent, having a high vapor pressure at temperatures {approx_equal}300 C and its subsequent condensation on and reaction with the other constituent (substrate) of an alloy thereby forming a controlled phase alloy and preferably a single phase alloy. It is preferred that the substrate material be a metal powder such that diffusion of the active metal constituent, preferably magnesium, and reaction therewith can be completed within a reasonable time and at temperatures {approx_equal}300 C thereby avoiding undesirable effects such as sintering, local compositional inhomogeneities, segregation, and formation of unwanted second phases such as intermetallic compounds. 4 figs.

  18. High mobility single-crystalline-like GaAs thin films on inexpensive flexible metal substrates by metal-organic chemical vapor deposition

    SciTech Connect (OSTI)

    Dutta, P. Rathi, M.; Gao, Y.; Yao, Y.; Selvamanickam, V.; Zheng, N.; Ahrenkiel, P.; Martinez, J.

    2014-09-01

    We demonstrate heteroepitaxial growth of single-crystalline-like n and p-type doped GaAs thin films on inexpensive, flexible, and light-weight metal foils by metal-organic chemical vapor deposition. Single-crystalline-like Ge thin film on biaxially textured templates made by ion beam assisted deposition on metal foil served as the epitaxy enabling substrate for GaAs growth. The GaAs films exhibited strong (004) preferred orientation, sharp in-plane texture, low grain misorientation, strong photoluminescence, and a defect density of ?10{sup 7?}cm{sup ?2}. Furthermore, the GaAs films exhibited hole and electron mobilities as high as 66 and 300?cm{sup 2}/V-s, respectively. High mobility single-crystalline-like GaAs thin films on inexpensive metal substrates can pave the path for roll-to-roll manufacturing of flexible III-V solar cells for the mainstream photovoltaics market.

  19. Development of (Re)BaCuO Coated Conductors by Liquid Phase Epitaxy

    E-Print Network [OSTI]

    Cheng, Yee Siau

    for novel technological applications, be it for energy and power applications, for levitation of trains, in medicine for MRI (Magnetic Resonance Imaging) tomography, or for SQUIDs (Superconducting Quantum Interference Devices) in magnetic encephalography... planes and only weakly coupled to their neighbours. For a magnetic field that is parallel to the c-direction, the flux pancakes form a simple stack, if the field is parallel to the a,b-plane, vortices may form between the superconducting planes...

  20. Water injection as a means for reducing non-condensible andcorrosive gases in steam produced from vapor-dominated reservoirs

    SciTech Connect (OSTI)

    Pruess, Karsten; Spycher, Nicolas; Kneafsey, Timothy J.

    2007-01-08

    Large-scale water injection at The Geysers, California, hasgenerated substantial benefits in terms of sustaining reservoir pressuresand production rates, as well as improving steam composition by reducingthe content of non-condensible gases (NCGs). Two effects have beenrecognized and discussed in the literature as contributing to improvedsteam composition, (1) boiling of injectate provides a source of "clean"steam to production wells, and (2) pressurization effects induced byboiling of injected water reduce upflow of native steam with large NCGconcentrations from depth. In this paper we focus on a possibleadditional effect that could reduce NCGs in produced steam by dissolutionin a condensed aqueous phase.Boiling of injectate causes pressurizationeffects that will fairly rapidly migrate outward, away from the injectionpoint. Pressure increases will cause an increase in the saturation ofcondensed phase due to vapor adsorption on mineral surfaces, andcapillary condensation in small pores. NCGs will dissolve in theadditional condensed phase which, depending upon their solubility, mayreduce NCG concentrations in residual steam.We have analyzed thepartitioning of HCl between vapor and aqueous phases, and have performednumerical simulations of injection into superheated vapor zones. Oursimulations provide evidence that dissolution in the condensed phase canindeed reduce NCG concentrations in produced steam.

  1. Vapor pressure isotope fractionation effects in planetary atmospheres: application to deuterium

    E-Print Network [OSTI]

    Thierry Fouchet; Emmanuel Lellouch

    1999-11-15

    The impact of the vapor pressure difference between deuterated and nondeuterated condensing molecules in planetary atmospheres is quantitatively assessed. This difference results in a loss of deuterium in the vapor phase above the condensation level. In Titan, Uranus and Neptune, the effect on CH3D is too subtle to alter current D/H ratio determinations. In Mars, the effect can induce a large depletion of HDO, starting about one scale height above the condensation level. Although the current infrared measurements of the D/H ratio appear to be almost unaffected, the intensity of disk-averaged millimetric HDO lines can be modified by about 10%. The effect is much stronger in limb sounding, and can be easily detected from orbiter observations.

  2. Processing-structure-property relationships in electron beam physical vapor deposited yttria stabilized zirconia coatings

    SciTech Connect (OSTI)

    Rao, D. Srinivasa; Valleti, Krishna; Joshi, S. V.; Janardhan, G. Ranga

    2011-05-15

    The physical and mechanical properties of yttria stabilized zirconia (YSZ) coatings deposited by the electron beam physical vapor deposition technique have been investigated by varying the key process variables such as vapor incidence angle and sample rotation speed. The tetragonal zirconia coatings formed under varying process conditions employed were found to have widely different surface and cross-sectional morphologies. The porosity, phase composition, planar orientation, hardness, adhesion, and surface residual stresses in the coated specimens were comprehensively evaluated to develop a correlation with the process variables. Under transverse scratch test conditions, the YSZ coatings exhibited two different crack formation modes, depending on the magnitude of residual stress. The influence of processing conditions on the coating deposition rate, column orientation angle, and adhesion strength has been established. Key relationships between porosity, hardness, and adhesion are also presented.

  3. G-Band Vapor Radiometer Profiler (GVRP) Handbook

    SciTech Connect (OSTI)

    Caddeau, MP

    2010-06-23

    The G-Band Vapor Radiometer Profiler (GVRP) provides time-series measurements of brightness temperatures from 15 channels between 170 and 183.310 GHz. Atmospheric emission in this spectral region is primarily due to water vapor, with some influence from liquid water. Channels between 170.0 and 176.0 GHz are particularly sensitive to the presence of liquid water. The sensitivity to water vapor of the 183.31-GHz line is approximately 30 times higher than at the frequencies of the two-channel microwave radiometer (MWR) for a precipitable water vapor (PWV) amount of less than 2.5 mm. Measurements from the GVRP instrument are therefore especially useful during low-humidity conditions (PWV < 5 mm). In addition to integrated water vapor and liquid water, the GVRP can provide low-resolution vertical profiles of water vapor in very dry conditions.

  4. Method and apparatus for concentrating vapors for analysis

    DOE Patents [OSTI]

    Grate, Jay W. (West Richland, WA); Baldwin, David L. (Kennewick, WA); Anheier, Jr., Norman C. (Richland, WA)

    2012-06-05

    A pre-concentration device and a method are disclosed for concentrating gaseous vapors for analysis. Vapors sorbed and concentrated within the bed of the pre-concentration device are thermally desorbed, achieving at least partial separation of the vapor mixtures. The pre-concentration device is suitable, e.g., for pre-concentration and sample injection, and provides greater resolution of peaks for vapors within vapor mixtures, yielding detection levels that are 10-10,000 times better than direct sampling and analysis systems. Features are particularly useful for continuous unattended monitoring applications. The invention finds application in conjunction with, e.g., analytical instruments where low detection limits for gaseous vapors are desirable.

  5. Dynamic Phase Boundaries for Compressible Fluids , Z. L. Xu

    E-Print Network [OSTI]

    New York at Stoney Brook, State University of

    is required for the study of cavitation induced by strong rarefaction waves. The robustness of the proposed of hydrodynamics and thermal effects in liquid-vapor phase transitions is en- countered in many applications-equilibrium effects. A complete macroscopic description of phase changes requires the coupling of hydrodynamics

  6. Vapor port and groundwater sampling well

    DOE Patents [OSTI]

    Hubbell, J.M.; Wylie, A.H.

    1996-01-09

    A method and apparatus have been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing. 10 figs.

  7. Vapor port and groundwater sampling well

    DOE Patents [OSTI]

    Hubbell, Joel M. (Idaho Falls, ID); Wylie, Allan H. (Idaho Falls, ID)

    1996-01-01

    A method and apparatus has been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing.

  8. Copper vapor laser acoustic thermometry system

    DOE Patents [OSTI]

    Galkowski, Joseph J. (Livermore, CA)

    1987-01-01

    A copper vapor laser (CVL) acoustic thermometry system is disclosed. The invention couples an acoustic pulse a predetermined distance into a laser tube by means of a transducer and an alumina rod such that an echo pulse is returned along the alumina rod to the point of entry. The time differential between the point of entry of the acoustic pulse into the laser tube and the exit of the echo pulse is related to the temperature at the predetermined distance within the laser tube. This information is processed and can provide an accurate indication of the average temperature within the laser tube.

  9. Category:Mercury Vapor | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmentalBowerbank,CammackFLIR Jump to: navigation,Ground GravityListsMercury Vapor Jump to:

  10. Controlled epitaxial graphene growth within removable amorphous carbon corrals

    SciTech Connect (OSTI)

    Palmer, James; Hu, Yike; Hankinson, John; Guo, Zelei; Heer, Walt A. de; Kunc, Jan; Berger, Claire

    2014-07-14

    We address the question of control of the silicon carbide (SiC) steps and terraces under epitaxial graphene on SiC and demonstrate amorphous carbon (aC) corrals as an ideal method to pin SiC surface steps. aC is compatible with graphene growth, structurally stable at high temperatures, and can be removed after graphene growth. For this, aC is first evaporated and patterned on SiC, then annealed in the graphene growth furnace. There at temperatures above 1200?°C, mobile SiC steps accumulate at the aC corral that provide effective step flow barriers. Aligned step free regions are thereby formed for subsequent graphene growth at temperatures above 1330?°C. Atomic force microscopy imaging supports the formation of step-free terraces on SiC with the step morphology aligned to the aC corrals. Raman spectroscopy indicates the presence of good graphene sheets on the step-free terraces.

  11. Method for controlling corrosion in thermal vapor injection gases

    DOE Patents [OSTI]

    Sperry, John S. (Houston, TX); Krajicek, Richard W. (Houston, TX)

    1981-01-01

    An improvement in the method for producing high pressure thermal vapor streams from combustion gases for injection into subterranean oil producing formations to stimulate the production of viscous minerals is described. The improvement involves controlling corrosion in such thermal vapor gases by injecting water near the flame in the combustion zone and injecting ammonia into a vapor producing vessel to contact the combustion gases exiting the combustion chamber.

  12. Advanced Chemical Heat Pumps Using Liquid-Vapor Reactions 

    E-Print Network [OSTI]

    Kirol, L.

    1987-01-01

    HEAT PUMPS USING LIQUID-VAPOR REACTIONS LANCE KIROL Senior Program Specialist Idaho National Engineering Laboratory Idaho Falls, Idaho . ABSTRACT Chemical heat pumps utilizing liquid-vapor reactions can be configured in forms analogous... to electric drive vapor-compression heat pumps and heat activated absorption heat pumps. Basic thermodynamic considerations eliminate some heat pumps and place restrictive working fluid requirements on others, but two thermodynam ically feasible systems...

  13. Review of enhanced vapor diffusion in porous media

    SciTech Connect (OSTI)

    Webb, S.W.; Ho, C.K.

    1998-08-01

    Vapor diffusion in porous media in the presence of its own liquid has often been treated similar to gas diffusion. The gas diffusion rate in porous media is much lower than in free space due to the presence of the porous medium and any liquid present. However, enhanced vapor diffusion has also been postulated such that the diffusion rate may approach free-space values. Existing data and models for enhanced vapor diffusion, including those in TOUGH2, are reviewed in this paper.

  14. M. Bahrami ENSC 461 (S 11) Vapor Power Cycles 1 Vapor Power Cycles

    E-Print Network [OSTI]

    Bahrami, Majid

    is not a suitable model for steam power cycle since: The turbine has to handle steam with low quality which will cause erosion and wear in turbine blades. It is impractical to design a compressor that handles two vapor expands isentropically in turbine and produces work. 4-1: Const P heat rejection High quality

  15. Micromechanical Resonators with Nanoporous Materials for Enhanced Vapor Sensing

    E-Print Network [OSTI]

    Hwang, Yong Ha

    2012-01-01

    organic compounds," Analytical Chemistry, vol. 74, pp. 3084-Gas Sensor Array," Analytical Chemistry, vol. 81, pp. 595-Chemical Vapors," Analytical Chemistry, vol. 83, pp. 3448-

  16. Thermodynamic and transport properties of sodium liquid and vapor...

    Office of Scientific and Technical Information (OSTI)

    sodium liquid and vapor. Recently published Russian recommendations and results of equation of state calculations on thermophysical properties of sodium have been included in...

  17. Direct-Current Resistivity Survey At Cove Fort Area - Vapor ...

    Open Energy Info (EERE)

    Direct-Current Resistivity Survey At Cove Fort Area - Vapor (Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity:...

  18. Direct-Current Resistivity Survey At Cove Fort Area - Vapor ...

    Open Energy Info (EERE)

    2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Direct-Current Resistivity Survey At Cove Fort Area - Vapor (Warpinski, Et Al., 2002)...

  19. Structure of epitaxial (Fe,N) codoped rutile TiO2 thin films by x-ray absorption

    SciTech Connect (OSTI)

    Kaspar, Tiffany C.; Ney, A.; Mangham, Andrew N.; Heald, Steve M.; Joly, Yves; Ney, V.; Wilhelm, F.; Rogalev, A.; Yakou, Flora; Chambers, Scott A.

    2012-07-23

    Homoepitaxial thin films of Fe:TiO2 and (Fe,N):TiO2 were deposited on rutile(110) by molecular beam epitaxy. X-ray absorption near edge spectroscopy (XANES) spectra were collected at the Ti L-edge, Fe L-edge, O K-edge, N K-edge, and Ti K-edge. No evidence of structural disorder associated with a high concentration of oxygen vacancies is observed. Substitution of Fe for Ti could not be confirmed, although secondary phase Fe2O3 and metallic Fe can be ruled out. The similarity of the N K-edge spectra to O, and the presence of a strong x-ray linear dichroism (XLD) signal for the N K-edge, indicates that N is substitutional for O in the rutile lattice, and is not present as a secondary phase such as TiN. Simulations of the XANES spectra qualitatively confirm substitution, although N appears to be present in more than one local environment. Neither Fe:TiO2 nor (Fe,N):TiO2 exhibit intrinsic room temperature ferromagnetism, despite the presence of mixed valence Fe(II)/Fe(III) in the reduced (Fe,N):TiO2 film.

  20. Field effect in epitaxial graphene on a silicon carbide substrate Sarnoff Corporation, CN5300, Princeton, New Jersey 08543

    E-Print Network [OSTI]

    Feenstra, Randall

    could be created by patterning 2D graphene into nanometers- wide strips2 to enable semiconductor1 Field effect in epitaxial graphene on a silicon carbide substrate Gong Gua) Sarnoff Corporation in epitaxially synthesized, as opposed to exfoliated, graphene. The graphene formed on the silicon face of a 4H

  1. Development of a Water Based, Critical Flow, Non-Vapor Compression cooling Cycle

    SciTech Connect (OSTI)

    Hosni, Mohammad H.

    2014-03-30

    Expansion of a high-pressure liquid refrigerant through the use of a thermostatic expansion valve or other device is commonplace in vapor-compression cycles to regulate the quality and flow rate of the refrigerant entering the evaporator. In vapor-compression systems, as the condensed refrigerant undergoes this expansion, its pressure and temperature drop, and part of the liquid evaporates. We (researchers at Kansas State University) are developing a cooling cycle that instead pumps a high-pressure refrigerant through a supersonic converging-diverging nozzle. As the liquid refrigerant passes through the nozzle, its velocity reaches supersonic (or critical-flow) conditions, substantially decreasing the refrigerant’s pressure. This sharp pressure change vaporizes some of the refrigerant and absorbs heat from the surrounding conditions during this phase change. Due to the design of the nozzle, a shockwave trips the supersonic two-phase refrigerant back to the starting conditions, condensing the remaining vapor. The critical-flow refrigeration cycle would provide space cooling, similar to a chiller, by running a secondary fluid such as water or glycol over one or more nozzles. Rather than utilizing a compressor to raise the pressure of the refrigerant, as in a vapor-cycle system, the critical-flow cycle utilizes a high-pressure pump to drive refrigerant liquid through the cooling cycle. Additionally, the design of the nozzle can be tailored for a given refrigerant, such that environmentally benign substances can act as the working fluid. This refrigeration cycle is still in early-stage development with prototype development several years away. The complex multi-phase flow at supersonic conditions presents numerous challenges to fully understanding and modeling the cycle. With the support of DOE and venture-capital investors, initial research was conducted at PAX Streamline, and later, at Caitin. We (researchers at Kansas State University) have continued development of the cycle and have gained an in-depth understanding of the governing fundamental knowledge, based on the laws of physics and thermodynamics and verified with our testing results. Through this research, we are identifying optimal working fluid and operating conditions to eventually demonstrate the core technology for space cooling or other applications.

  2. An ultra-thin buffer layer for Ge epitaxial layers on Si

    SciTech Connect (OSTI)

    Kawano, M.; Yamada, S.; Tanikawa, K.; Miyao, M.; Hamaya, K. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan)] [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Sawano, K. [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Tokyo 158-0082 (Japan)] [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Tokyo 158-0082 (Japan)

    2013-03-25

    Using an Fe{sub 3}Si insertion layer, we study epitaxial growth of Ge layers on a Si substrate by a low-temperature molecular beam epitaxy technique. When we insert only a 10-nm-thick Fe{sub 3}Si layer in between Si and Ge, epitaxial Ge layers can be obtained on Si. The detailed structural characterizations reveal that a large lattice mismatch of {approx}4% is completely relaxed in the Fe{sub 3}Si layer. This means that the Fe{sub 3}Si layers can become ultra-thin buffer layers for Ge on Si. This method will give a way to realize a universal buffer layer for Ge, GaAs, and related devices on a Si platform.

  3. Structural controlled magnetic anisotropy in Heusler L1{sub 0}-MnGa epitaxial thin films

    SciTech Connect (OSTI)

    Wang Kangkang; Lu Erdong; Smith, Arthur R.; Knepper, Jacob W.; Yang Fengyuan

    2011-04-18

    Ferromagnetic L1{sub 0}-MnGa thin films have been epitaxially grown on GaN, sapphire, and MgO substrates using molecular beam epitaxy. Using diffraction techniques, the epitaxial relationships are determined. It is found that the crystalline orientation of the films differ due to the influence of the substrate. By comparing the magnetic anisotropy to the structural properties, a clear correlation could be established indicating that the in-plane and out-of-plane anisotropy is directly determined by the crystal orientation of the film and could be controlled via selection of the substrates. This result could be helpful in tailoring magnetic anisotropy in thin films for spintronic applications.

  4. Vapor and gas sampling of Single-Shell Tank 241-A-101 using the Vapor Sampling System

    SciTech Connect (OSTI)

    Caprio, G.S.

    1995-11-01

    This document presents sampling data resulting from the June 8, 1995, sampling of SST 241-A-101 using the Vapor Sampling System.

  5. Materials Science and Engineering B 127 (2006) 9197 Short communication

    E-Print Network [OSTI]

    Anderson, Timothy J.

    2006-01-01

    Materials Science and Engineering B 127 (2006) 91­97 Short communication Oxynitride mediated epitaxy of gallium nitride on silicon(1 1 1) substrates in a merged hydride/metal-organic vapor phase epitaxy system M.A. Mastro, O.M. Kryliouk, T.J. Anderson Department of Chemical Engineering, University

  6. Reduced gravity rankine cycle design and optimization with passive vortex phase separation 

    E-Print Network [OSTI]

    Supak, Kevin Robert

    2009-05-15

    turbo machinery, require kilowatts of power and are untested for high vapor flow conditions. The Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive microgravity vortex phase separator (MVS) which has already proven...

  7. Interface characterization of epitaxial Fe/MgO/Fe magnetic tunnel junctions

    SciTech Connect (OSTI)

    Wang, Shouguo; Ward, R. C. C.; Zhang, Xiaoguang; Kohn, A.; Ma, Q. L.; Zhang, J.; Liu, H. F.; Han, Prof. X. F.

    2012-01-01

    Following predictions by first-principles theory of huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratio about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, MR ratio of about 600% has been reported at RT in MgO-based amorphous MTJs with core structure of CoFeB/MgO/CoFeB grown by magnetron sputtering with amorphous CoFeB layers. The sputtered CoFeB/MgO/CoFeB MTJs shows a great potential application in spintronic devices. Although epitaxial structure will probably not be used in devices, it remains an excellent model system to compare theoretical calculations with experimental results and to enhance our understanding of the spin dependent tunneling. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role on coherent tunneling across single crystalMgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism have been used for interface characterization. However, no consistent viewpoint has been reached, and this is still an open issue. In this article, recent studies on the interface characterization in MgO-based epitaxial MTJs will be introduced, with a focus on research by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin dependent tunneling spectroscopy.

  8. Structure-property correlation in epitaxial (2 0 0) rutile films on sapphire substrates

    SciTech Connect (OSTI)

    Bayati, M.R.; Joshi, Sh.; Molaei, R.; Narayan, R.J.; Narayan, J.

    2012-03-15

    We have investigated the influence of the deposition variables on photocatalytic properties of epitaxial rutile films. Despite a large lattice misfit of rutile with sapphire substrate, (2 0 0) epitaxial layers were grown on (0 0 0 1)sapphire by domain matching epitaxy paradigm. Using {phi}-scan XRD and cross section TEM, the epitaxial relationship was determined to be rutile(1 0 0)||sapphire(0 0 0 1), rutile(0 0 1)||sapphire(1 0 -1 0), and rutile(0 1 0)||sapphire(1 -2 1 0). Based on the XRD patterns, increasing the repetition rate introduced tensile stress along the film normal direction, which may arise as a result of trapped defects. Formation of such defects was studied by UV-VIS, PL, and XPS techniques. AFM studies showed that the film roughness increases with the repetition rate. Finally, photocatalytic performance of the layers was investigated through measuring decomposition rate of 4-chlorophenol on the films surface. The films grown at higher frequencies revealed higher photocatalytic efficiency. This behavior was mainly related to formation of point defects which enhance the charge separation. - Graphical abstract: In this report, epitaxial rutile TiO{sub 2} thin films were deposited by PLD process under various deposition rates (frequencies) and their physical and chemical properties, especially photocatalytic performance, were investigated. It was found that photocatalytic efficiency improves when frequency increases. This behavior was mainly related to formation of point defects which enhance the charge separation. Highlights: Black-Right-Pointing-Pointer Rutile epitaxial thin films were deposited via PLD process under different frequencies. Black-Right-Pointing-Pointer Defect characteristic was studied. Black-Right-Pointing-Pointer Photocatalytic performance of the layers was investigated.

  9. The Water Vapor Abundance in Orion KL Outflows

    E-Print Network [OSTI]

    J. Cernicharo; J. R. Goicoechea; F. Daniel; M. R. Lerate; M. J. Barlow; B. M. Swinyard; E. van Dishoeck; T. L. Lim; S. Viti; J. Yates

    2006-08-16

    We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, towards Orion KL. Observations were performed with the Long Wavelength Spectrometer Fabry-Perot (LWS/FP; R~6800-9700) on board the Infrared Space Observatory (ISO) between ~43 and ~197 um. The water line profiles evolve from P-Cygni type profiles (even for the H2O18 lines) to pure emission at wavelengths above ~100 um. We find that most of the water emission/absorption arises from an extended flow of gas expanding at 25+-5 kms^-1. Non-local radiative transfer models show that much of the water excitation and line profile formation is driven by the dust continuum emission. The derived beam averaged water abundance is 2-3x10^-5. The inferred gas temperature Tk=80-100 K suggests that: (i) water could have been formed in the "plateau" by gas phase neutral-neutral reactions with activation barriers if the gas was previously heated (e.g. by shocks) to >500 K and/or (ii) H2O formation in the outflow is dominated by in-situ evaporation of grain water-ice mantles and/or (iii) H2O was formed in the innermost and warmer regions (e.g. the hot core) and was swept up in ~1000 yr, the dynamical timescale of the outflow.

  10. Chromium Vaporization Reduction by Nickel Coatings For SOEC Interconnect Materials

    SciTech Connect (OSTI)

    Michael V. Glazoff; Sergey N. Rashkeev; J. Stephen Herring

    2014-09-01

    The vaporization of Cr-rich volatile species from interconnect materials is a major source of degradation that limits the lifetime of planar solid oxide devices systems with metallic interconnects, including Solid Oxide Electrolysis Cells, or SOECs. Some metallic coatings (Ni, Co, and Cu) significantly reduce the Cr release from interconnects and slow down the oxide scale growth on the steel substrate. To shed additional light upon the mechanisms of such protection and find a suitable coating material for ferritic stainless steel materials, we used a combination of first-principles calculations, thermodynamics, and diffusion modeling to investigate which factors determine the quality of the Ni metallic coating at stainless steel interconnector. We found that the Cr migration in Ni coating is determined by a delicate combination of the nickel oxidation, Cr diffusion, and phase transformation processes. Although the formation of Cr2O3 oxide is more exothermic than that of NiO, the kinetic rate of the chromia formation in the coating layer and its surface is significantly reduced by the low mobility of Cr in nickel oxide and in NiCr2O4 spinel. These results are in a good agreement with diffusion modeling for Cr diffusion through Ni coating layer on the ferritic 441 steel substrate.

  11. Magnetism and transport properties of epitaxial Fe-Ga thin films on GaAs(001)

    SciTech Connect (OSTI)

    Duong Anh Tuan; Shin, Yooleemi; Cho, Sunglae; Dang Duc Dung; Vo Thanh Son

    2012-04-01

    Epitaxial Fe-Ga thin films in disordered bcc {alpha}-Fe crystal structure (A2) have been grown on GaAs(001) by molecular beam epitaxy. The saturated magnetization (M{sub S}) decreased from 1371 to 1105 kA/m with increasing Ga concentration from 10.5 to 24.3 % at room temperature. The lattice parameter increased with the increase in Ga content because of the larger atomic radius of Ga atom than that of Fe. The increase in carrier density with Ga content caused in lower resistivity.

  12. Perpendicularly magnetized {tau}-MnAl (001) thin films epitaxied on GaAs

    SciTech Connect (OSTI)

    Nie, S. H.; Zhu, L. J.; Lu, J.; Pan, D.; Wang, H. L.; Yu, X. Z.; Xiao, J. X.; Zhao, J. H.

    2013-04-15

    Perpendicularly magnetized {tau}-MnAl films have been epitaxied on GaAs (001) by molecular-beam epitaxy. Crystalline quality and magnetic properties of the samples were strongly dependent on growth temperature. The highest coercivity of 10.7 kOe, saturation magnetization of 361.4 emu/cm{sup 3}, perpendicular magnetic anisotropy constant of 13.65 Merg/cm{sup 3}, and magnetic energy product of 4.44 MGOe were achieved. These tunable magnetic properties make MnAl films valuable as excellent and cost-effective alternative for not only high density perpendicular magnetic recording storage and spintronics devices but also permanent magnets.

  13. Effect of substrate temperature on the magnetic properties of epitaxial sputter-grown Co/Pt

    SciTech Connect (OSTI)

    Mihai, A. P.; Whiteside, A. L.; Canwell, E. J.; Marrows, C. H.; Moore, T. A.; Benitez, M. J.; McGrouther, D.; McVitie, S.; McFadzean, S.

    2013-12-23

    Epitaxial Co/Pt films have been deposited by dc-magnetron sputtering onto heated C-plane sapphire substrates. X-ray diffraction, the residual resistivity, and transmission electron microscopy indicate that the Co/Pt films are highly ordered on the atomic scale. The coercive field and the perpendicular magnetic anisotropy increase as the substrate temperature is increased from 100–250?°C during deposition of the Co/Pt. Measurement of the domain wall creep velocity as a function of applied magnetic field yields the domain wall pinning energy, which scales with the coercive field. Evidence for an enhanced creep velocity in highly ordered epitaxial Co/Pt is found.

  14. Surface photovoltage method for the quality control of silicon epitaxial layers on sapphire

    SciTech Connect (OSTI)

    Yaremchuk, A. F.; Starkov, A. V.; Zaikin, A. V., E-mail: lynch0000@gmail.com [National Rsearch University MIET (Russian Federation); Alekseev, A. V. [ZAO “Telekom-STV” (Russian Federation); Sokolov, E. M. [ZAO “Epiel” (Russian Federation)

    2014-12-15

    The surface photovoltage method is used to study “silicon-on-sapphire” epitaxial layers with a thickness of 0.3–0.6 ?m, which are used to fabricate p-channel MOS (metal—oxide-semiconductor) transistors with improved radiation hardness. It is shown that the manner in which the photoconductivity of the epitaxial layer decays after the end of a light pulse generated by a light-emitting diode (wavelength ?400 nm) strongly depends on the density of structural defects in the bulk of the structure. This enables control over how a “silicon-on-sapphire” structure is formed to provide the manufacturing of MOS structures with optimal operating characteristics.

  15. Myers et al. Page 1 Use of High Temperature Hydrogen Annealing to

    E-Print Network [OSTI]

    Myers, Tom

    , Department of Chemical Engineering West Virginia University, Morgantown, WV 26506 J. Alam, Electrical Eng growth of GaN and AlN as well as with thick, "free-standing" layers grown by hydride vapor phase epitaxy in this study were Ga-polar GaN layers grown on (0001) sapphire grown at TDI, Inc. using hydride vapor phase

  16. UNCORRECTEDPROOF Please cite this article in press as: D. Lipkind et al., The vaporization enthalpies and vapor pressures of a series of unsaturated fatty acids methyl

    E-Print Network [OSTI]

    Chickos, James S.

    enthalpies and vapor pressures of a series of unsaturated fatty acids methyl esters by correlation gas­8 Thermochimica Acta xxx (2007) xxx­xxx The vaporization enthalpies and vapor pressures of a series of unsaturated- vonate (methyl Z 15-tetracosenoate) are evaluated at T = 298.15 and vapor pressures are evaluated over

  17. Chemical vapor detection with a multispectral thermal imager

    E-Print Network [OSTI]

    Chang, Chein-I

    Chemical vapor detection with a multispectral thermal imager Mark 1. G. Aithouse, MEMBER SPIE U.S. Army Chemical Research Development and Engineering Center SMCCR-DDT Aberdeen Proving Ground, Maryland algorithm 7. Conclusions 8. Acknowledgments 9. References 1. INTRODUCTION Detection of chemical vapor clouds

  18. Recuperative Vapor Recompression Heat Pumps for Cryogenic Air Separation

    E-Print Network [OSTI]

    Ahrendt, Wolfgang

    Air N2 CW MAC MHE LP HP CW N2 O2 Recuperative Vapor Recompression Heat Pumps for Cryogenic Air · The compression of O2 in the air feed is avoided by applying recuperative vapor recompression heat pumps) heat pump The compression of B can be avoided 77 79 81 83 85 87 89 91 93 -5000 5000 15000 25000 35000

  19. ADHESION FORCES BETWEEN MICA SURFACES IN UNDERSATURATED VAPORS OF HYDROCARBONS

    E-Print Network [OSTI]

    Matsuoka, Hiroshige

    ADHESION FORCES BETWEEN MICA SURFACES IN UNDERSATURATED VAPORS OF HYDROCARBONS H. MATSUOKA1 , T] or meniscus force [3], which have been neglected in the conventional and relatively large mechani- cal systems forces between mica surfaces in under- saturated vapors of several kind of hydrocarbon liquids are mea

  20. RESONANT FARADAY ROTATION IN A HOT LITHIUM VAPOR

    E-Print Network [OSTI]

    Cronin, Alex D.

    RESONANT FARADAY ROTATION IN A HOT LITHIUM VAPOR By SCOTT RUSSELL WAITUKAITIS A Thesis Submitted: #12;Abstract I describe a study of Faraday rotation in a hot lithium vapor. I begin by dis- cussing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 The Lithium Oven and Solenoid . . . . . . . . . . . . . . . . . 7 3 Theoretical Framework

  1. Epitaxial growth of 100-?m thick M-type hexaferrite crystals on wide bandgap semiconductor GaN/Al{sub 2}O{sub 3} substrates

    SciTech Connect (OSTI)

    Hu, Bolin; Su, Zhijuan; Bennett, Steve; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07

    Thick barium hexaferrite BaFe{sub 12}O{sub 19} (BaM) films having thicknesses of ?100??m were epitaxially grown on GaN/Al{sub 2}O{sub 3} substrates from a molten-salt solution by vaporizing the solvent. X-ray diffraction measurement verified the growth of BaM (001) textured growth of thick films. Saturation magnetization, 4?M{sub s}, was measured for as-grown films to be 4.6 ± 0.2 kG and ferromagnetic resonance measurements revealed a microwave linewidth of ?100?Oe at X-band. Scanning electron microscopy indicated clear hexagonal crystals distributed on the semiconductor substrate. These results demonstrate feasibility of growing M-type hexaferrite crystal films on wide bandgap semiconductor substrates by using a simple powder melting method. It also presents a potential pathway for the integration of ferrite microwave passive devices with active semiconductor circuit elements creating system-on-a-wafer architectures.

  2. Petrology and geochemistry of Alto Peak, a vapor-cored hydrothermal system, Leyte Province, Philippines

    SciTech Connect (OSTI)

    Reyes, A.G.; Giggenbach, W.F.; Saleras, J.R.M.; Salonga, N.D.; Vergara, M.C.

    1993-10-01

    Based on detailed petrological information on secondary mineral assemblages and the composition of fluids trapped in inclusions and discharged from five wells, the Alto Peak geothermal field was found to represent a combined vapor and liquid-dominated system. A central core or chimney, with a diameter of about 1 km, a height of some 3 km and occupied by a high gas vapor (1.1 to 5.6 molal CO{sub 2}), is surrounded by an envelope of intermediate salinity water (7,000 mg/kg Cl) with temperatures between 250 and 350 C. The transition from purely vapor-dominated to liquid-dominated zones takes place via two-phase zones occupied by fluid mixtures of highly variable compositions. Much of the lower temperature, mature neutral pH Cl water is likely to have formed during an earlier stage in the evolution of the system. High temperatures of > 300 C, and associated alteration, are limited to wells AP-1D and the lower parts of AP-2D and are ascribed to re-heating by recent magmatic intrusions. The isotopic composition of the well discharges suggests that they contain some 40 to 50% of magmatic water. Alto Peak is considered a typical example of hydrothermal systems associated with many dormant volcanoes.

  3. Oxide vapor distribution from a high-frequency sweep e-beam system

    SciTech Connect (OSTI)

    Chow, R.; Tassano, P.L.; Tsujimoto, N.

    1995-03-01

    Oxide vapor distributions have been determined as a function of operating parameters of a high frequency sweep e-beam source combined with a programmable sweep controller. We will show which parameters are significant, the parameters that yield the broadest oxide deposition distribution, and the procedure used to arrive at these conclusions. A design-of-experimental strategy was used with five operating parameters: evaporation rate, sweep speed, sweep pattern (pre-programmed), phase speed (azimuthal rotation of the pattern), profile (dwell time as a function of radial position). A design was chosen that would show which of the parameters and parameter pairs have a statistically significant effect on the vapor distribution. Witness flats were placed symmetrically across a 25 inches diameter platen. The stationary platen was centered 24 inches above the e-gun crucible. An oxide material was evaporated under 27 different conditions. Thickness measurements were made with a stylus profilometer. The information will enable users of the high frequency e-gun systems to optimally locate the source in a vacuum system and understand which parameters have a major effect on the vapor distribution.

  4. Kinetics of wet sodium vapor complex plasma

    SciTech Connect (OSTI)

    Mishra, S. K., E-mail: nishfeb@rediffmail.com [Institute for Plasma Research (IPR), Gandhinagar 382428 (India); Sodha, M. S. [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)] [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)

    2014-04-15

    In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.

  5. Chemical vapor deposition of group IIIB metals

    DOE Patents [OSTI]

    Erbil, A.

    1989-11-21

    Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula given in the patent where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula 1 is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula 1 and a heat decomposable tellurium compound under nonoxidizing conditions.

  6. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    SciTech Connect (OSTI)

    Westwater, Edgeworth

    2011-05-06

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of this contract, we participated in another ARM-sponsored experiment at the NSA during February-March 2007. This experiment is called the Radiative Heating in Underexplored Bands Campaign (RHUBC) and the GSR was operated successfully for the duration of the campaign. One of the principal goals of the experiment was to provide retrievals of water vapor during PWV amounts less than 2 mm and to compare GSR data with ARM radiometers and radiosondes. A secondary goal was to compare the radiometric response of the microwave and millimeter wavelength radiometers to water and ice clouds. In this final report, we will include the separate progress reports for each of the three years of the project and follow with a section on major accomplishments of the project.

  7. Controlled VLS Growth of Indium, Gallium and Tin Oxide Nanowires via Chemical Vapor Transport

    E-Print Network [OSTI]

    Johnson, M.C.; Aloni, S.; McCready, D.E.; Bourret-Courchesne, E.D.

    2006-01-01

    6 Growth Rate (um/hr) Vapor Pressure (Torr) In2O3 Ga2O3 SnO2Rate (µm/hr) Metal Vapor Pressure (Torr) Crystalline phaseto the source metal vapor pressure. Initial experiments show

  8. Gas Separation Using Organic-Vapor-Resistent Membranes In Conjunctin With Organic-Vapor-Selective Membranes

    DOE Patents [OSTI]

    Baker, Richard W. (Palo Alto, CA); Pinnau, Ingo (Palo Alto, CA); He, Zhenjie (Fremont, CA); Da Costa, Andre R. (Menlo Park, CA); Daniels, Ramin (San Jose, CA); Amo, Karl D. (Mountain View, CA); Wijmans, Johannes G. (Menlo Park, CA)

    2003-06-03

    A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

  9. Hybrid Vapor Compression Adsorption System: Thermal Storage Using Hybrid Vapor Compression Adsorption System

    SciTech Connect (OSTI)

    2012-01-04

    HEATS Project: UTRC is developing a new climate-control system for EVs that uses a hybrid vapor compression adsorption system with thermal energy storage. The targeted, closed system will use energy during the battery-charging step to recharge the thermal storage, and it will use minimal power to provide cooling or heating to the cabin during a drive cycle. The team will use a unique approach of absorbing a refrigerant on a metal salt, which will create a lightweight, high-energy-density refrigerant. This unique working pair can operate indefinitely as a traditional vapor compression heat pump using electrical energy, if desired. The project will deliver a hot-and-cold battery that provides comfort to the passengers using minimal power, substantially extending the driving range of EVs.

  10. Studies on multi-phase equilibrium separation of hydrocarbon/water systems 

    E-Print Network [OSTI]

    Chawla, Inderjit Singh

    1995-01-01

    varying from C6 to C20. PVT-VLLE apparatus can provide on-line compositional analysis and phase volumes of all equilibrium phases for temperatures up to 350 'F and an Isochoric Steam Distillation Cell (ISDC) can provide only vapor phase compositions...

  11. Isobaric vapor-liquid equilibria of the water + 1-propanol system at 30, 60, and 100 kPa

    SciTech Connect (OSTI)

    Gabaldon, C.; Marzal, P.; Monton, J.B.; Rodrigo, M.A. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica] [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

    1996-09-01

    Isobaric vapor-liquid equilibria for the water + 1-propanol system are reported at 30, 60, and 100 kPa. The results were found to be thermodynamically consistent according to Van Ness-Byer-Gibbs, Kojima, and Wisniak methods. The system shows a minimum boiling azeotrope, and the azeotropic composition is scarcely shifted with pressure. Results were compared with literature values. The data were correlated with Margules, Van Laar, Wilson, NRTL, and UNIQUAC liquid-phase activity coefficient models.

  12. Lattice mismatched epitaxy of heterostructures for non-nitride green light emitting devices

    E-Print Network [OSTI]

    Mori, Michael James

    2008-01-01

    In this project, we implement modern metal organic chemical vapor deposition (MOCVD) technology to fabricate monolithic platforms which integrate traditionally incompatible materials with the ultimate goal of achieving ...

  13. Semi-epitaxial magnetic tunnel transistor: Effect of electron energy and temperature

    E-Print Network [OSTI]

    Bayreuther, Günther

    ; published online 6 May 2005 A magnetic tunnel transistor with spin-valve metallic base and epitaxial collector leakage. © 2005 American Institute of Physics. DOI: 10.1063/1.1853892 I. INTRODUCTION The hot-electron spin-valve transistor was introduced by Monsma et al. in 1995.1 Since then, interest in hot

  14. Journal of Crystal Growth 304 (2007) 399401 Growth of high quality, epitaxial InSb nanowires

    E-Print Network [OSTI]

    Wang, Zhong L.

    2007-01-01

    Journal of Crystal Growth 304 (2007) 399­401 Growth of high quality, epitaxial InSb nanowires Hyun, Washington, DC. 20375, USA b School of Materials Science and Engineering, Georgia Institute of Technology March 2007 Communicated by R.M. Biefeld Available online 1 April 2007 Abstract The growth of In

  15. Stabilizing Graphitic Thin Films of Wurtzite Materials by Epitaxial Strain Dangxin Wu,1

    E-Print Network [OSTI]

    Simons, Jack

    numbers: 81.15.Aa, 64.70.Nd, 68.35.BÀ, 73.20.At Modern materials growth and synthesis technology have allowed the creation of materials that do not exist in nature. Epitaxial growth of thin films, one such technology, creates novel materials by employing two mechanisms: (1) grow thermodynamically metastable thin

  16. Local deformations and incommensurability of high quality epitaxial graphene on a weakly interacting transition metal

    E-Print Network [OSTI]

    parameter mismatch when cooling down the sample from the graphene preparation temperature to the measurement to the preparation conditions. All these effects are consistent with initial growth and subsequent pining of grapheneLocal deformations and incommensurability of high quality epitaxial graphene on a weakly

  17. EVOLUTION AND REGULARITY RESULTS FOR EPITAXIALLY STRAINED THIN FILMS AND MATERIAL VOIDS

    E-Print Network [OSTI]

    Segatti, Antonio

    EVOLUTION AND REGULARITY RESULTS FOR EPITAXIALLY STRAINED THIN FILMS AND MATERIAL VOIDS PAOLO PIOVANO Abstract. We consider free boundary problems that model the evolution of interfaces, and the surface energy, which has a stabilizing effect. First, we introduce the evolution equation with curvature

  18. Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

    DOE Patents [OSTI]

    Chang, Y. Austin (Middleton, WI); Yang, Jianhua Joshua (Madison, WI)

    2008-11-11

    This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

  19. Characterization of Epitaxial Film Silicon Solar Cells Grown on Seeded Display Glass: Preprint

    SciTech Connect (OSTI)

    Young, D. L.; Grover, S.; Teplin, C.; Stradins, P.; LaSalvia, V.; Chuang, T. K.; Couillard, J. G.; Branz, H. M.

    2012-06-01

    We report characterizations of epitaxial film crystal silicon (c-Si) solar cells with open-circuit voltages (Voc) above 560 mV. The 2-um absorber cells are grown by low-temperature (<750 degrees C) hot-wire CVD (HWCVD) on Corning EAGLE XG display glass coated with a layer-transferred (LT) Si seed. The high Voc is a result of low-defect epitaxial Si (epi-Si) growth and effective hydrogen passivation of defects. The quality of HWCVD epitaxial growth on seeded glass substrates depends on the crystallographic quality of the seed and the morphology of the epitaxial growth surface. Heterojunction devices consist of glass/c-Si LT seed/ epi n+ Si:P/epi n- Si:P/intrinsic a-Si:H/p+ a-Si:H/ITO. Similar devices grown on electronically 'dead' n+ wafers have given Voc {approx}630 mV and {approx}8% efficiency with no light trapping features. Here we study the effects of the seed surface polish on epi-Si quality, how hydrogenation influences the device character, and the dominant junction transport physics.

  20. Tunneling evidence of half-metallicity in epitaxial films of ferromagnetic perovskite manganites and ferrimagnetic magnetite

    E-Print Network [OSTI]

    Yeh, Nai-Chang

    Tunneling evidence of half-metallicity in epitaxial films of ferromagnetic perovskite manganites with the perovskite manganites are discussed. © 1998 American Institute of Physics. S0021-8979 98 45811-0 Half magnetoresistance CMR in the perovskite manganites, Ln1 xMxMnO3 Ln: trivalent rare earth ions, M divalent alkaline

  1. Surface Reaction Kinetics of Ga 1x In x P Growth During Pulsed Chemical Beam Epitaxy

    E-Print Network [OSTI]

    Surface Reaction Kinetics of Ga 1­x In x P Growth During Pulsed Chemical Beam Epitaxy N. Dietz 1 growth has been a slow process because little is known about chemical reaction properties and reaction into the surface reaction kinetics during an organometallic deposition process. These insights will allow us

  2. Silicon epitaxy below 200C: Towards thin crystalline solar cells R. Carioua,b

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . However material still represent more than 40% of the cost of c-Si PV Thin Film Solar Technology IV-Si) technology. Indeed, the learning curve of c-Si solar cells has reached a plateau since 1999 with the 25Silicon epitaxy below 200°C: Towards thin crystalline solar cells R. Carioua,b , R. Ruggeria,c , P

  3. Enhanced surface diffusion through termination conversion during epitaxial SrRuO3 growth

    E-Print Network [OSTI]

    Eom, Chang Beom

    Enhanced surface diffusion through termination conversion during epitaxial SrRuO3 growth Guus of the ferromagnetic oxide SrRuO3 on TiO2-terminated SrTiO3 , we observe a self-organized conversion of the terminating to surface termination and growth mode.6 Because their application is mostly in mirror-symmetric trilayer

  4. Nanostaircases: An atomic shadowing instability during epitaxial CrN,,001... layer growth

    E-Print Network [OSTI]

    Gall, Daniel

    Nanostaircases: An atomic shadowing instability during epitaxial CrN,,001... layer growth J. R the effect of atomic shadowing on surface morphological and microstructural evolution. The layers are single deposition flux than the surrounding layer. This leads to both vertical and lateral growth and the formation

  5. Epitaxial crystals of Bi?Pt?O? pyrochlore through the transformation of ?–Bi?O? fluorite

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gutiérrez–Llorente, Araceli; Joress, Howie; Woll, Arthur; Holtz, Megan E.; Ward, Matthew J.; Sullivan, Matthew C.; Muller, David A.; Brock, Joel D.

    2015-03-01

    Bi?Pt?O? pyrochlore is thought to be one of the most promising oxide catalysts for application in fuel cell technology. Unfortunately, direct film growth of Bi?Pt?O? has not yet been achieved, owing to the difficulty of oxidizing platinum metal in the precursor material to Pt??. In this work, in order to induce oxidation of the platinum, we annealed pulsed laser deposited films consisting of epitaxial ?–Bi?O? and co-deposited, comparatively disordered platinum. We present synchrotron x-ray diffraction results that show the nonuniform annealed films contain the first epitaxial crystals of Bi?Pt?O?. We also visualized the pyrochlore structure by scanning transmission electron microscopy,more »and observed ordered cation vacancies in the epitaxial crystals formed in a bismuth-rich film but not in those formed in a platinum-rich film. The similarity between the ?–Bi?O? and Bi?Pt?O? structures appears to facilitate the pyrochlore formation. These results provide the only route to date for the formation of epitaxial Bi?Pt?O?.« less

  6. Domain Engineering for Enhanced Ferroelectric Properties of Epitaxial (001) BiFeO Thin Films

    E-Print Network [OSTI]

    Eom, Chang Beom

    Domain Engineering for Enhanced Ferroelectric Properties of Epitaxial (001) BiFeO Thin Films By Ho of conventional Ti-rich lead zirconia titanate, suggested BiFeO3 as a strong candidate for lead-free nonvolatile are simultaneously improved by domain engineering. For the demonstration of the domain variant selection in BiFeO3

  7. GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies

    E-Print Network [OSTI]

    Rogers, John A.

    LETTERS GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies and high electron mobilities. Examples range from effi- cient photovoltaic devices1,2 to radio and logic gates on plates of glass, near-infrared imaging devices on wafers of silicon, and photovoltaic

  8. Epitaxially grown colloidal crystals of silica microspheres on patterned substrate of triangular arrays

    E-Print Network [OSTI]

    Braun, Paul

    Epitaxially grown colloidal crystals of silica microspheres on patterned substrate of triangular by colloidal crystallization were rigorously examined in real-space using a laser scanning confocal microscopy. In wet colloidal crystals, both systems showed a strong preference toward face centered cubic (fcc

  9. Properties of molecular beam epitaxy grown Eu{sub x}(transition metal){sub y} films (transition metals: Mn, Cr)

    SciTech Connect (OSTI)

    Balin, K.; Nowak, A.; Gibaud, A.; Szade, J.; Celinski, Z.

    2011-04-01

    The electronic and crystallographic structures, as well as the magnetic properties, of Eu{sub x}(transition metal){sub y} (transition metals: Mn, Cr) thin films grown by molecular beam epitaxy were studied. Relative changes of the Eu/Mn and Eu/Cr ratios derived from the XPS lines, as well as x-ray reflectivity, indicate mixing of the Eu/Mn and Eu/Cr layers. Valency transitions from Eu{sup 2+} to Eu{sup 3+} were observed in both systems for most studied stoichiometries. A transition to a magnetically ordered phase was observed at 15 K, 40 K, and 62 K for selected films in the Eu-Mn system, and at 50 K for the film with a Eu/Cr ratio of 0.5.

  10. Enlarged Mn 3s splitting and room-temperature ferromagnetism in epitaxially grown oxygen doped Mn{sub 2}N{sub 0.86} films

    SciTech Connect (OSTI)

    Meng, M.; Wu, S. X. Ren, L. Z.; Zhou, W. Q.; Wang, Y. J.; Wang, G. L.; Li, S. W.

    2014-11-07

    Single-phase and oxygen doped Mn{sub 2}N{sub 0.86} thin films have been grown on MgO (111) by plasma-assisted molecular beam epitaxy. The films grow under tensile strain and, remarkably, they show ferromagnetic-like interactions at low temperature and ferromagnetic ordering agreed well with the Bloch-law T{sup 3/2} at room-temperature. We further demonstrate the enlarged Mn 3s splitting (6.46?eV) and its possible relation to the observed ferromagnetism. Our study not only provide a strategy for further theoretical work on oxygen doped manganese nitrides, but also shed promising light on utilizing its room-temperature FM property to fabricate spintronic devices.

  11. Enhancement of pyroelectric signal by continuous ultraviolet illumination of epitaxial Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} films

    SciTech Connect (OSTI)

    Pintilie, L.; Iuga, A. [National Institute of Materials Physics, Atomistilor 105bis, Magurele, Ilfov 077125 (Romania); Botea, M. [National Institute of Materials Physics, Atomistilor 105bis, Magurele, Ilfov 077125 (Romania); Faculty of Physics, University of Bucharest, Magurele 077125 (Romania)

    2014-09-29

    The pyroelectric signal generated by an epitaxial Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} film can be enhanced by continuous illumination with ultraviolet (UV) light. The measured signal increases more than 2 times at low modulation frequencies of the incident infrared (IR) radiation (?10?Hz) and at wavelengths where the short-circuit photocurrent presents the maximum value (?280–300?nm). The tentative explanation is that the changes in polarization induced by the temperature variation under modulated IR illumination are generating a variable internal electric field, able to collect the photogenerated carriers produced under continuous UV illumination leading to an additional signal in phase with the pyroelectric one. This finding could be exploited for designing pyroelectric detectors with enhanced characteristics by combining both UV and IR responses.

  12. Step-edge-induced resistance anisotropy in quasi-free-standing bilayer chemical vapor deposition graphene on SiC

    SciTech Connect (OSTI)

    Ciuk, Tymoteusz [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland); Cakmakyapan, Semih; Ozbay, Ekmel [Department of Electrical and Electronics Engineering, Department of Physics, Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Ankara (Turkey); Caban, Piotr; Grodecki, Kacper; Pasternak, Iwona; Strupinski, Wlodek, E-mail: wlodek.strupinski@itme.edu.pl [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Krajewska, Aleksandra [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Institute of Optoelectronics, Military University of Technology, Gen. S. Kaliskiego 2, 00-908 Warsaw (Poland); Szmidt, Jan [Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland)

    2014-09-28

    The transport properties of quasi-free-standing (QFS) bilayer graphene on SiC depend on a range of scattering mechanisms. Most of them are isotropic in nature. However, the SiC substrate morphology marked by a distinctive pattern of the terraces gives rise to an anisotropy in graphene's sheet resistance, which may be considered an additional scattering mechanism. At a technological level, the growth-preceding in situ etching of the SiC surface promotes step bunching which results in macro steps ~10 nm in height. In this report, we study the qualitative and quantitative effects of SiC steps edges on the resistance of epitaxial graphene grown by chemical vapor deposition. We experimentally determine the value of step edge resistivity in hydrogen-intercalated QFS-bilayer graphene to be ~190 ??m for step height hS = 10 nm and provide proof that it cannot originate from mechanical deformation of graphene but is likely to arise from lowered carrier concentration in the step area. Our results are confronted with the previously reported values of the step edge resistivity in monolayer graphene over SiC atomic steps. In our analysis, we focus on large-scale, statistical properties to foster the scalable technology of industrial graphene for electronics and sensor applications.

  13. Magnetic properties of MnSb inclusions formed in GaSb matrix directly during molecular beam epitaxial growth

    SciTech Connect (OSTI)

    Lawniczak-Jablonska, Krystyna; Wolska, Anna; Klepka, Marcin T.; Kret, Slawomir; Kurowska, Boguslawa; Kowalski, Bogdan J.; Twardowski, Andrzej; Wasik, Dariusz; Kwiatkowski, Adam; Sadowski, Janusz

    2011-04-01

    Despite of intensive search for the proper semiconductor base materials for spintronic devices working at room temperature no appropriate material based on ferromagnetic semiconductors has been found so far. We demonstrate that the phase segregated system with MnSb hexagonal inclusions inside the GaSb matrix, formed directly during the molecular beam epitaxial growth reveals the ferromagnetic properties at room temperature and is a good candidate for exploitation in spintronics. Furthermore, the MnSb inclusions with only one crystalline structure were identified in this GaMn:MnSb granular material. The SQUID magnetometry confirmed that this material exhibits ferromagnetic like behavior starting from helium up to room temperature. Moreover, the magnetic anisotropy was found which was present also at room temperature, and it was proved that by choosing a proper substrate it is possible to control the direction of easy axis of inclusions' magnetization moment between in-plane and out-of-plane; the latter is important in view of potential applications in spintronic devices.

  14. Monitoring PVD metal vapors using laser absorption spectroscopy

    SciTech Connect (OSTI)

    Braun, D.G.; Anklam, T.M.; Berzins, L.V.; Hagans, K.G.

    1994-04-01

    Laser absorption spectroscopy (LAS) has been used by the Atomic Vapor Laser Isotope Separation (AVLIS) program for over 10 years to monitor the co-vaporization of uranium and iron in its separators. During that time, LAS has proven to be an accurate and reliable method to monitor both the density and composition of the vapor. It has distinct advantages over other rate monitors, in that it is completely non-obtrusive to the vaporization process and its accuracy is unaffected by the duration of the run. Additionally, the LAS diagnostic has been incorporated into a very successful process control system. LAS requires only a line of sight through the vacuum chamber, as all hardware is external to the vessel. The laser is swept in frequency through an absorption line of interest. In the process a baseline is established, and the line integrated density is determined from the absorption profile. The measurement requires no hardware calibration. Through a proper choice of the atomic transition, a wide range of elements and densities have been monitored (e.g. nickel, iron, cerium and gadolinium). A great deal of information about the vapor plume can be obtained from the measured absorption profiles. By monitoring different species at the same location, the composition of the vapor is measured in real time. By measuring the same density at different locations, the spatial profile of the vapor plume is determined. The shape of the absorption profile is used to obtain the flow speed of the vapor. Finally, all of the above information is used evaluate the total vaporization rate.

  15. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    SciTech Connect (OSTI)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE flowchart provides a structured process to determine if the technology is, or is not, reasonable and defensible for a particular site. The central basis for that decision is the expected performance of PSVE under the site specific conditions. Will PSVE have sufficient mass removal rates to reduce the release, or flux, of contamination into the underlying groundwater so that the site can meet it overall remedial objectives? The summary technical information, case study experiences, and structured decision process provided in this 'user guide' should assist environmental decision-makers, regulators, and engineers in selecting and successfully implementing PSVE at appropriate sites.

  16. Controlling the vapor pressure of a mercury lamp

    DOE Patents [OSTI]

    Grossman, Mark W. (Belmont, MA); George, William A. (Rockport, MA)

    1988-01-01

    The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled.

  17. Controlling the vapor pressure of a mercury lamp

    DOE Patents [OSTI]

    Grossman, M.W.; George, W.A.

    1988-05-24

    The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled. 2 figs.

  18. Pool boilup analysis using the TRANSIT-HYDRO code with improved vapor/liquid drag models. [LMFBR

    SciTech Connect (OSTI)

    Wigeland, R.A.; Graff, D.L.

    1984-01-01

    The TRANSIT-HYDRO computer code is being developed to provide a tool for assessing the consequences of transition phase events in a hypothetical core disruptive accident in an LMFBR. The TRANSIT-HYDRO code incorporates detailed geometric modeling on a subassembly-by-subassembly basis and detailed modeling of reactor material behavior and thermal and hydrodynamic phenomena. The purpose of this summary is to demonstrate the validity of the improved vapor/liquid momentum exchange models in the TRANSIT-HYDRO code for a prototypic experiment and describe some implications for transition phase scenarios.

  19. Catalytic Reactor For Oxidizing Mercury Vapor

    DOE Patents [OSTI]

    Helfritch, Dennis J. (Baltimore, MD)

    1998-07-28

    A catalytic reactor (10) for oxidizing elemental mercury contained in flue gas is provided. The catalyst reactor (10) comprises within a flue gas conduit a perforated corona discharge plate (30a, b) having a plurality of through openings (33) and a plurality of projecting corona discharge electrodes (31); a perforated electrode plate (40a, b, c) having a plurality of through openings (43) axially aligned with the through openings (33) of the perforated corona discharge plate (30a, b) displaced from and opposing the tips of the corona discharge electrodes (31); and a catalyst member (60a, b, c, d) overlaying that face of the perforated electrode plate (40a, b, c) opposing the tips of the corona discharge electrodes (31). A uniformly distributed corona discharge plasma (1000) is intermittently generated between the plurality of corona discharge electrode tips (31) and the catalyst member (60a, b, c, d) when a stream of flue gas is passed through the conduit. During those periods when corona discharge (1000) is not being generated, the catalyst molecules of the catalyst member (60a, b, c, d) adsorb mercury vapor contained in the passing flue gas. During those periods when corona discharge (1000) is being generated, ions and active radicals contained in the generated corona discharge plasma (1000) desorb the mercury from the catalyst molecules of the catalyst member (60a, b, c, d), oxidizing the mercury in virtually simultaneous manner. The desorption process regenerates and activates the catalyst member molecules.

  20. Water Vapor around Sgr B2

    E-Print Network [OSTI]

    J. Cernicharo; J. R. Goicoechea; J. R. Pardo; A. Asensio Ramos

    2006-01-16

    We have conducted a study combining H2O lines in two spectral regions. First, Infrared Space Observatory observations of several H2O thermal lines seen in absorption toward Sgr B2(M) at a spectral resolution of 35 kms^-1 have been analyzed. Second, an IRAM-30m telescope map of the para-H2O 3_13-2_20 line at 183.31 GHz, seen in emission, has also been obtained and analyzed. The H2O lines seen in absorption are optically thick and are formed in the outermost gas of the condensations in front of the far-IR continuum sources. They probe a maximum visual extinction of ~5 to 10 mag. Radiative transfer models indicate that these lines are quite insensitive to temperature and gas density, and that IR photons from the dust play a dominant role in the excitation of the involved H2O rotational levels. The water vapor abundance in the region is (1-2)x10^-5. The relatively low H2O/OH abundance ratio in the region, 2-4, is a signature of UV photon dominated surface layers traced by far-IR observations.

  1. Optimization of Xenon Difluoride Vapor Delivery

    SciTech Connect (OSTI)

    Sweeney, Joseph; Marganski, Paul; Kaim, Robert; Wodjenski, Mike; Gregg, John; Yedave, Sharad; Sergi, Steve; Bishop, Steve; Eldridge, David; Zou Peng [ATMI, Inc., Danbury, Connecticut 06810 (United States)

    2008-11-03

    Xenon difluoride (XeF{sub 2}) has been shown to provide many process benefits when used as a daily maintenance recipe for ion implant. Regularly flowing XeF{sub 2} into the ion source cleans the deposits generated by ion source operation. As a result, significant increases in productivity have been demonstrated. However, XeF{sub 2} is a toxic oxidizer that must be handled appropriately. Furthermore, it is a low vapor pressure solid under standard conditions ({approx}4.5 torr at 25 deg. C). These aspects present unique challenges for designing a package for delivering the chemistry to an ion implanter. To address these challenges, ATMI designed a high-performance, re-usable cylinder for dispensing XeF{sub 2} in an efficient and reliable manner. Data are presented showing specific attributes of the cylinder, such as the importance of internal heat transfer media and the cylinder valve size. The impact of mass flow controller (MFC) selection and ion source tube design on the flow rate of XeF{sub 2} are also discussed. Finally, cylinder release rate data are provided.

  2. The Atomic Vapor Laser Isotope Separation Program

    SciTech Connect (OSTI)

    Not Available

    1992-11-09

    This report provides the finding and recommendations on the audit of the Atomic Vapor Laser Isotope Separation (AVLIS) program. The status of the program was assessed to determine whether the Department was achieving objectives stated in its January 1990 Plan for the Demonstration, Transition and Deployment of AVLIS Technology. Through Fiscal Year 1991, the Department had spent about $1.1 billion to develop AVLIS technology. The January 1990 plan provided for AVLIS to be far enough along by September to enable the Department to make a determination of the technical and economic feasibility of deployment. However, the milestones needed to support that determination were not met. An estimated $550 million would be needed to complete AVLIS engineering development and related testing prior to deployment. The earliest possible deployment date has slipped to beyond the year 2000. It is recommended that the Department reassess the requirement for AVLIS in light of program delays and changes that have taken place in the enrichment market since January 1990. Following the reassessment, a decision should be made to either fully support and promote the actions needed to complete AVLIS development or discontinue support for the program entirely. Management`s position is that the Department will successfully complete the AVLIS technology demonstration and that the program should continue until it can be transferred to a Government corporation. Although the auditors recognize that AVLIS may be transferred, there are enough technical and financial uncertainties that a thorough assessment is warranted.

  3. Dispersion of seed vapor and gas ionization in an MHD second stage combustor and channel

    SciTech Connect (OSTI)

    Chang, S.L.; Lottes, S.A.; Bouillard, J.X.

    1992-01-01

    An approach is introduced for the simulation of a magnetohydrodynamic system consisting of a second stage combustor, a convergent nozzle, and a channel. The simulation uses an Argonne integral combustion flow computer code and another Argonne channel computer code to predict flow, thermal and electric properties in the seed particle laden reacting flow in the system. The combustion code is a general hydrodynamics computer code for two-phase, two-dimensional, turbulent, and reacting flows, based on mass, momentum, and energy conservation laws for gaseous and condensed phases. The channel code is a multigrid three-dimensional computer code for compressible flow subject to magnetic and electric interactions. Results of this study suggests that (1) the processes of seed particle evaporation, seed vapor dispersion, and gas ionization in the reacting flow are critical to the evaluation of the downstream channel performance and (2) particle size, loading, and inlet profile have strong effects on wall deposition and plasma temperature development.

  4. Dispersion of seed vapor and gas ionization in an MHD second stage combustor and channel

    SciTech Connect (OSTI)

    Chang, S.L.; Lottes, S.A.; Bouillard, J.X.

    1992-07-01

    An approach is introduced for the simulation of a magnetohydrodynamic system consisting of a second stage combustor, a convergent nozzle, and a channel. The simulation uses an Argonne integral combustion flow computer code and another Argonne channel computer code to predict flow, thermal and electric properties in the seed particle laden reacting flow in the system. The combustion code is a general hydrodynamics computer code for two-phase, two-dimensional, turbulent, and reacting flows, based on mass, momentum, and energy conservation laws for gaseous and condensed phases. The channel code is a multigrid three-dimensional computer code for compressible flow subject to magnetic and electric interactions. Results of this study suggests that (1) the processes of seed particle evaporation, seed vapor dispersion, and gas ionization in the reacting flow are critical to the evaluation of the downstream channel performance and (2) particle size, loading, and inlet profile have strong effects on wall deposition and plasma temperature development.

  5. University of Oregon: GPS-based Precipitable Water Vapor (PWV)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Vignola, F.; Andreas, A.

    2013-08-22

    A partnership with the University of Oregon and U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to collect Precipitable Water Vapor (PWV) data to compliment existing resource assessment data collection by the university.

  6. Enabling integration of vapor-deposited polymer thin films

    E-Print Network [OSTI]

    Petruczok, Christy D. (Christy Danielle)

    2014-01-01

    Initiated Chemical Vapor Deposition (iCVD) is a versatile, one-step process for synthesizing conformal and functional polymer thin films on a variety of substrates. This thesis emphasizes the development of tools to further ...

  7. Initiated chemical vapor deposition of functional polyacrylic thin films

    E-Print Network [OSTI]

    Mao, Yu, 1975-

    2005-01-01

    Initiated chemical vapor deposition (iCVD) was explored as a novel method for synthesis of functional polyacrylic thin films. The process introduces a peroxide initiator, which can be decomposed at low temperatures (<200?C) ...

  8. Chemical vapor deposition of organosilicon and sacrificial polymer thin films

    E-Print Network [OSTI]

    Casserly, Thomas Bryan

    2005-01-01

    Chemical vapor deposition (CVD) produced films for a wide array of applications from a variety of organosilicon and organic precursors. The structure and properties of thin films were controlled by varying processing ...

  9. Photoinitiated chemical vapor depostion [sic] : mechanism and applications

    E-Print Network [OSTI]

    Baxamusa, Salmaan Husain

    2009-01-01

    Photoinitiated chemical vapor deposition (piCVD) is developed as a simple, solventless, and rapid method for the deposition of swellable hydrogels and functional hydrogel copolymers. Mechanistic experiments show that piCVD ...

  10. Systems and methods for generation of hydrogen peroxide vapor

    DOE Patents [OSTI]

    Love, Adam H; Eckels, Joel Del; Vu, Alexander K; Alcaraz, Armando; Reynolds, John G

    2014-12-02

    A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above a hydrogen peroxide solution in the second container for producing a hydrogen peroxide vapor. A method according one embodiment includes at least one of bubbling dried air through a hydrogen peroxide solution in a container for producing a first hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above the hydrogen peroxide solution in a container for producing a second hydrogen peroxide vapor. Additional systems and methods are also presented.

  11. Water vapor and the dynamics of climate changes

    E-Print Network [OSTI]

    Schneider, Tapio

    Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus ...

  12. Fatigue Resistance of Asphalt Mixtures Affected by Water Vapor Movement 

    E-Print Network [OSTI]

    Tong, Yunwei

    2013-11-08

    This dissertation has two key objectives: the first objective is to develop a method of predicting and quantifying the amount of water that can enter into a pavement system by vapor transport; the second objective is to ...

  13. All graphene electromechanical switch fabricated by chemical vapor deposition

    E-Print Network [OSTI]

    Milaninia, Kaveh M.

    We demonstrate an electromechanical switch comprising two polycrystalline graphene films; each deposited using ambient pressure chemical vapor deposition. The top film is pulled into electrical contact with the bottom film ...

  14. Low Level Heat Recovery Through Heat Pumps and Vapor Recompression 

    E-Print Network [OSTI]

    Gilbert, J.

    1980-01-01

    The intent of this paper is to examine the methods and economics of recovering low level heat through heat pumps and vapor recompression. Actual commercially available equipment is considered to determine the near-term and future economic viability...

  15. University of Oregon: GPS-based Precipitable Water Vapor (PWV)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Vignola, F.; Andreas, A.

    A partnership with the University of Oregon and U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to collect Precipitable Water Vapor (PWV) data to compliment existing resource assessment data collection by the university.

  16. Use Vapor Recompression to Recover Low-Pressure Waste Steam,...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    that it can be reused. Vapor recompression relies upon a mechanical compressor or steam jet ejector to increase the temperature of the latent heat in steam to render it usable for...

  17. Effect of furnace operating conditions on alkali vaporization...

    Office of Scientific and Technical Information (OSTI)

    on alkali vaporization, batch carryover, and the formation of SO2 and NO in an oxy-fuel fired container glass furnace. Citation Details In-Document Search Title: Effect of...

  18. Numerical analysis of vapor flow in a micro heat pipe 

    E-Print Network [OSTI]

    Liu, Xiaoqin

    1996-01-01

    The vapor flow in a flat plate micro heat pipe with both uniform and linear heat flux boundary conditions has been numerically analyzed. For both types of boundary conditions, the Navier-Stokes equations with steady incompressible two...

  19. Screw Type Steam Compressors for Mechanical Vapor Recompression (MVR) Systems 

    E-Print Network [OSTI]

    Kawamura, K.; Apaloo, Thomas-L.

    1986-01-01

    hand, is not affected by such problem. No special mist separator is required and, at the same time, the wet or saturated vapor compression is possible, and does not affect the efficiency of the SSHP. (3) Stability of performance for a wide... COMPRESSORS FOR MECHANICAL VAPOR RECOMPRESSION (MVR) SYSTEMS K. KAWAMURA AND THOMAS-L. APALOO MYCOM CORPORATION, LOS ANGELES, CALIFORNIA MATSUDA, MAYEKAWA MFG. CO., TOKYO, JAPAN ABSTRACT In processes of evaporation, distillation or drying, steam...

  20. Injection locked oscillator system for pulsed metal vapor lasers

    DOE Patents [OSTI]

    Warner, Bruce E. (Livermore, CA); Ault, Earl R. (Dublin, CA)

    1988-01-01

    An injection locked oscillator system for pulsed metal vapor lasers is disclosed. The invention includes the combination of a seeding oscillator with an injection locked oscillator (ILO) for improving the quality, particularly the intensity, of an output laser beam pulse. The present invention includes means for matching the first seeder laser pulses from the seeding oscillator to second laser pulses of a metal vapor laser to improve the quality, and particularly the intensity, of the output laser beam pulse.

  1. PROJECT PROFILE: Stable Perovskite Solar Cells via Chemical Vapor Deposition

    Broader source: Energy.gov [DOE]

    This project is focused on novel approaches to remove risk related to the development of hybrid perovskite solar cells (HPSCs). Researchers will synthesize a new and chemically stable hybrid organic-inorganic perovskite that eliminates decomposition of the absorber layer upon exposure to water vapor, which is a chief obstacle to widespread use of HPSC technology. They will also demonstrate a unique and industrially-scalable chemical vapor deposition method without halides or iodine, which are the main contributors to perovskite degradation.

  2. Evidence for graphite-like hexagonal AlN nanosheets epitaxially grown on single crystal Ag(111)

    SciTech Connect (OSTI)

    Tsipas, P.; Kassavetis, S.; Tsoutsou, D.; Xenogiannopoulou, E.; Golias, E.; Giamini, S. A.; Dimoulas, A.; Grazianetti, C.; Fanciulli, M.; Dipartimento di Scienza dei Materiali, Università degli Studi di Milano Bicocca, I-20126, Milano ; Chiappe, D.; Molle, A.

    2013-12-16

    Ultrathin (sub-monolayer to 12 monolayers) AlN nanosheets are grown epitaxially by plasma assisted molecular beam epitaxy on Ag(111) single crystals. Electron diffraction and scanning tunneling microscopy provide evidence that AlN on Ag adopts a graphite-like hexagonal structure with a larger lattice constant compared to bulk-like wurtzite AlN. This claim is further supported by ultraviolet photoelectron spectroscopy indicating a reduced energy bandgap as expected for hexagonal AlN.

  3. ARM: Microwave Radiometer data (MWR Profiles - QME), water vapor, temp, cloud liquid water, precip water retrievals

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Maria Cadeddu

    2004-02-19

    Microwave Radiometer data (MWR Profiles - QME), water vapor, temp, cloud liquid water, precip water retrievals

  4. ARM: Microwave Radiometer data (MWR Profiles - QME), water vapor, temp, cloud liquid water, precip water retrievals

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Maria Cadeddu

    Microwave Radiometer data (MWR Profiles - QME), water vapor, temp, cloud liquid water, precip water retrievals

  5. Continuous phase transition and negative specific heat in finite nuclei

    E-Print Network [OSTI]

    J. N. De; S. K. Samaddar; S. Shlomo; J. B. Natowitz

    2006-01-30

    The liquid-gas phase transition in finite nuclei is studied in a heated liquid-drop model where the nuclear drop is assumed to be in thermodynamic equilibrium with its own evaporated nucleonic vapor conserving the total baryon number and isospin of the system. It is found that in the liquid-vapor coexistence region the pressure is not a constant on an isotherm indicating that the transition is continuous. At constant pressure, the caloric curve shows some anomalies, namely, the systems studied exhibit negative heat capacity in a small temperature domain. The dependence of this specific feature on the mass and isospin of the nucleus, Coulomb interaction and the chosen pressure is studied. The effects of the presence of clusters in the vapor phase on specific heat have also been explored.

  6. Strain-induced orbital polarization and multiple phase transitions in Ba{sub 2}MnWO{sub 6} from first principles

    SciTech Connect (OSTI)

    Ju, Weiwei; Zhao, Bao; Yang, Zhongqin

    2013-11-28

    Electronic structures of double perovskite Ba{sub 2}MnWO{sub 6} with epitaxial strain are explored by using methods based on density functional theory. An in-plane compressive strain is found not only resulting in a semiconductor-metal transition (SMT), but also altering the magnetic structures, from different kinds of antiferromagnetic to ferromagnetic orders. Orbital polarization and different orbital occupancies of Mn d{sub z{sup 2}} and d{sub x{sup 2}?y{sup 2}} states, induced by the epitaxial strain, are employed to understand the SMT. The rich magnetic phase transitions are rationalized by a magnetic stabilization mechanism. Our results show that many technological applications may be carried out in the material with the control of epitaxial strain.

  7. Phase Change Heat Transfer Device for Process Heat Applications

    SciTech Connect (OSTI)

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2010-10-01

    The next generation nuclear plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to approx.1300 K) and industrial scale power transport (=50MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a thermal device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization/condensing process. The condensate is further returned to the hot source by gravity, i.e., without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) of vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

  8. One-step aluminium-assisted crystallization of Ge epitaxy on Si by magnetron sputtering

    SciTech Connect (OSTI)

    Liu, Ziheng, E-mail: ziheng.liu@unsw.edu.au; Hao, Xiaojing; Ho-Baillie, Anita; Green, Martin A. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052 (Australia)

    2014-02-03

    In this work, one-step aluminium-assisted crystallization of Ge on Si is achieved via magnetron sputtering by applying an in-situ low temperature (50?°C to 150?°C) heat treatment in between Al and Ge depositions. The effect of heat treatment on film properties and the growth mechanism of Ge epitaxy on Si are studied via X-ray diffraction, Raman and transmission electron microscopy analyses. Compared with the conventional two-step process, the one-step aluminium-assisted crystallization requires much lower thermal budget and results in pure Ge epitaxial layer, which may be suitable for use as a virtual substrate for the fabrication of III-V solar cells.

  9. Pseudorotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Steinrück, H. -G.; Magerl, A.; Deutsch, M.; Ocko, B. M.

    2014-10-06

    The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ~1% – 3% to the sapphire’s and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in themore »crystalline coherence length of the SAM’s powderlike crystallites when rotationally aligned with the sapphire’s lattice. As a result, the increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.« less

  10. Pseudo-rotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)

    SciTech Connect (OSTI)

    Steinruck, H. -G.; Ocko, B. M.; Magerl, A.; Deutsch, M.

    2014-10-06

    The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ~1% – 3% to the sapphire’s and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in the crystalline coherence length of the SAM’s powderlike crystallites when rotationally aligned with the sapphire’s lattice. The increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.

  11. Extrinsic anomalous Hall effect in epitaxial Mn{sub 4}N films

    SciTech Connect (OSTI)

    Meng, M.; Wu, S. X. Ren, L. Z.; Zhou, W. Q.; Wang, Y. J.; Wang, G. L.; Li, S. W.

    2015-01-19

    Anomalous Hall effect (AHE) in ferrimagnetic Mn{sub 4}N epitaxial films grown by molecular-beam epitaxy is investigated. The longitudinal conductivity ?{sub xx} is within the superclean regime, indicating Mn{sub 4}N is a highly conducting material. We further demonstrate that the AHE signal in 40-nm-thick films is mainly due to the extrinsic contributions based on the analysis fitted by ?{sub AH}=a??{sub xx0}+b?{sub xx}{sup 2} and ?{sub AH}??{sub xx}. Our study not only provide a strategy for further theoretical work on antiperovskite manganese nitrides but also shed promising light on utilizing their extrinsic AHE to fabricate spintronic devices.

  12. Pseudo-rotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)

    SciTech Connect (OSTI)

    Steinruck, H. -G. [Univ. of Erlangen-Nurnberg, Erlangen (Germany); Ocko, B. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Magerl, A. [Univ. of Erlangen-Nurnberg, Erlangen (Germany); Deutsch, M. [Bar-Ilan Univ., Ramat-Gan (Israel)

    2014-10-01

    The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ~1% – 3% to the sapphire’s and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in the crystalline coherence length of the SAM’s powderlike crystallites when rotationally aligned with the sapphire’s lattice. The increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.

  13. Thin film GaAs solar cells on glass substrates by epitaxial liftoff

    SciTech Connect (OSTI)

    Lee, X.Y.; Goertemiller, M.; Boroditsky, M.; Ragan, R.; Yablonovitch, E.

    1997-02-01

    In this work, we describe the fabrication and operating characteristics of GaAs/AlGaAs thin film solar cells processed by the epitaxial liftoff (ELO) technique. This technique allows the transfer of these cells onto glass substrates. The performance of the lifted-off solar cell is demonstrated by means of electrical measurements under both dark and illuminated conditions. We have also optimized the light trapping conditions in this direct-gap material. The results show that good solar absorption is possible in active layers as thin as 0.32 {mu}m. In such a thin solar cell, the open circuit voltage would be enhanced. We believe that the combination of an epitaxial liftoff thin GaAs film, and nano-texturing can lead to record breaking performance. {copyright} {ital 1997 American Institute of Physics.}

  14. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOE Patents [OSTI]

    McKee, Rodney Allen (Kingston, TN); Walker, Frederick Joseph (Oak Ridge, TN)

    1998-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  15. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    DOE Patents [OSTI]

    McKee, Rodney A. (Kingston, TN); Walker, Frederick J. (Oak Ridge, TN)

    1995-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  16. Pseudo-rotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Steinruck, H. -G.; Ocko, B. M.; Magerl, A.; Deutsch, M.

    2014-10-06

    The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ~1% – 3% to the sapphire’s and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in themore »crystalline coherence length of the SAM’s powderlike crystallites when rotationally aligned with the sapphire’s lattice. The increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.« less

  17. Continuous ultra-thin MoS{sub 2} films grown by low-temperature physical vapor deposition

    SciTech Connect (OSTI)

    Muratore, C. [Department of Chemical and Materials Engineering, University of Dayton, Dayton, Ohio 45469 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Hu, J. J.; Bultman, J. E.; Jespersen, M. L. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); University of Dayton Research Institute, Dayton, Ohio 45469 (United States); Wang, B.; Haque, M. A. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, College Park, Pennsylvania 16802 (United States); Shamberger, P. J.; McConney, M. E.; Naguy, R. D.; Voevodin, A. A. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)

    2014-06-30

    Uniform growth of pristine two dimensional (2D) materials over large areas at lower temperatures without sacrifice of their unique physical properties is a critical pre-requisite for seamless integration of next-generation van der Waals heterostructures into functional devices. This Letter describes a vapor phase growth technique for precisely controlled synthesis of continuous, uniform molecular layers of MoS{sub 2} on silicon dioxide and highly oriented pyrolitic graphite substrates of over several square centimeters at 350?°C. Synthesis of few-layer MoS{sub 2} in this ultra-high vacuum physical vapor deposition process yields materials with key optical and electronic properties identical to exfoliated layers. The films are composed of nano-scale domains with strong chemical binding between domain boundaries, allowing lift-off from the substrate and electronic transport measurements from contacts with separation on the order of centimeters.

  18. Isobaric vapor-liquid equilibria of the water + 2-propanol system at 30, 60, and 100 kPa

    SciTech Connect (OSTI)

    Marzal, P.; Monton, J.B.; Rodrigo, M.A. [Univ. de Valencia (Spain). Departamento de Ingenieria Quimica] [Univ. de Valencia (Spain). Departamento de Ingenieria Quimica

    1996-05-01

    Distillation is perhaps the separation process most widely used in the chemical processing industry. The correct design of distillation columns requires the availability of accurate and, if possible, thermodynamically consistent vapor-liquid equilibria (VLE) data. The present work is part of a project studying the effect of pressure on the behavior of the azeotropic point in mixtures in which at least one component is an alcohol. Isobaric vapor-liquid equilibria were obtained for the water + 2-propanol system at 30, 60, and 100 kPa. The activity coefficients were found to be thermodynamically consistent by the methods of Van Ness-Byer-Gibbs, Kojima, and Wisniak. The data were correlated with five liquid phase activity coefficient models (Margules, Van Laar, Wilson, NRTL, and UNIQUAC).

  19. Experimental study of the distribution of alloying elements after the formation of epitaxial ferrite upon cooling in a low-carbon steel

    SciTech Connect (OSTI)

    Santofimia, M.J.; Kwakernaak, C.; Sloof, W.G.; Zhao, L.; Sietsma, J.

    2010-10-15

    The distributions of carbon and substitutional elements in a low-carbon steel during the formation of epitaxial ferrite on cooling after intercritical annealing have been studied by electron probe microanalysis (EPMA). The analysis has shown that the formation of epitaxial ferrite takes place with a partial redistribution of alloying elements between the epitaxial ferrite and the austenite. This redistribution of alloying elements causes compositional gradients in the epitaxial ferrite that lead to a different etching behaviour with respect to the intercritical ferrite. Contrary to Thermo-Calc predictions, a distinct partitioning behaviour of silicon has been observed.

  20. Molecular Beam Epitaxial Growth of GaAs on (631) Oriented Substrates

    SciTech Connect (OSTI)

    Cruz Hernandez, Esteban; Rojas Ramirez, Juan-Salvador; Contreras Hernandez, Rocio; Lopez Lopez, Maximo; Pulzara Mora, Alvaro; Mendez Garcia, Victor H.

    2007-02-09

    In this work, we report the study of the homoepitaxial growth of GaAs on (631) oriented substrates by molecular beam epitaxy (MBE). We observed the spontaneous formation of a high density of large scale features on the surface. The hilly like features are elongated towards the [-5, 9, 3] direction. We show the dependence of these structures with the growth conditions and we present the possibility of to create quantum wires structures on this surface.

  1. Method of fabricating low-dislocation-density epitaxially-grown films with textured surfaces

    DOE Patents [OSTI]

    Li, Qiming; Wang, George T

    2015-01-13

    A method for forming a surface-textured single-crystal film layer by growing the film atop a layer of microparticles on a substrate and subsequently selectively etching away the microparticles to release the surface-textured single-crystal film layer from the substrate. This method is applicable to a very wide variety of substrates and films. In some embodiments, the film is an epitaxial film that has been grown in crystallographic alignment with respect to a crystalline substrate.

  2. Low-temperature grown graphene films by using molecular beam epitaxy

    SciTech Connect (OSTI)

    Lin, Meng-Yu [Institute of Electronics, National Taiwan University, Taipei, Taiwan (China); Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Guo, Wei-Ching; Wang, Pro-Yao [Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung, Taiwan (China); Wu, Meng-Hsun [College of Photonics, National Chiao-Tung University, Tainan, Taiwan (China); Liu, Te-Huan; Chang, Chien-Cheng [Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan (China); Pao, Chun-Wei; Lin, Shih-Yen [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei, Taiwan (China); Lee, Si-Chen [Institute of Electronics, National Taiwan University, Taipei, Taiwan (China)

    2012-11-26

    Complete graphene film is prepared by depositing carbon atoms directly on Cu foils in a molecular beam epitaxy chamber at 300 Degree-Sign C. The Raman spectrum of the film has indicated that high-quality few-layer graphene is obtained. With back-gated transistor architecture, the characteristic current modulation of graphene transistors is observed. Following the similar growth procedure, graphitization is observed at room temperature, which is consistent with the molecular dynamics simulations of graphene growth.

  3. Fabrication of precision high quality facets on molecular beam epitaxy material

    DOE Patents [OSTI]

    Petersen, Holly E. (Tracy, CA); Goward, William D. (Antioch, CA); Dijaili, Sol P. (Moraga, CA)

    2001-01-01

    Fabricating mirrored vertical surfaces on semiconductor layered material grown by molecular beam epitaxy (MBE). Low energy chemically assisted ion beam etching (CAIBE) is employed to prepare mirrored vertical surfaces on MBE-grown III-V materials under unusually low concentrations of oxygen in evacuated etching atmospheres of chlorine and xenon ion beams. UV-stabilized smooth-surfaced photoresist materials contribute to highly vertical, high quality mirrored surfaces during the etching.

  4. Tuning carrier density across Dirac point in epitaxial graphene on SiC by corona discharge

    SciTech Connect (OSTI)

    Lartsev, Arseniy; Yager, Tom; Lara-Avila, Samuel, E-mail: samuel.lara@chalmers.se; Kubatkin, Sergey [Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg (Sweden); Bergsten, Tobias [SP Technical Research Institute of Sweden, S-50115 Borås (Sweden); Tzalenchuk, Alexander [National Physical Laboratory, Teddington TW110LW (United Kingdom); Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Janssen, T. J. B. M [National Physical Laboratory, Teddington TW110LW (United Kingdom); Yakimova, Rositza [Department of Physics, Chemistry and Biology (IFM), Linköping University, S-58183 Linköping (Sweden)

    2014-08-11

    We demonstrate reversible carrier density control across the Dirac point (?n???10{sup 13?}cm{sup ?2}) in epitaxial graphene on SiC (SiC/G) via high electrostatic potential gating with ions produced by corona discharge. The method is attractive for applications where graphene with a fixed carrier density is needed, such as quantum metrology, and more generally as a simple method of gating 2DEGs formed at semiconductor interfaces and in topological insulators.

  5. Possibility of Gravitational Tempering in Colloidal Epitaxy to Obtain a Perfect Crystal

    E-Print Network [OSTI]

    Mori, Atsushi; Matsuo, Shigeki

    2012-01-01

    We have performed Monte Carlo simulations of hard spheres on a pattern under gravity. We have found that a crystal formed at a moderate gravity strength contains essentially no defects while one formed at a higher strength gravity contains a significant amount of defects. This result suggests the possibility of using gravitational-tempering in a colloidal epitaxy to reduce the number of defects in colloidal crystals. Moreover, we wish to emphasize the possibility to obtain a perfect crystal.

  6. Suppression of Octahedral Tilts and Associated Changes in Electronic Properties at Epitaxial Oxide Heterostructure Interfaces

    E-Print Network [OSTI]

    Pennycook, Steve

    Heterostructure Interfaces A. Y. Borisevich,1,* H. J. Chang,1 M. Huijben,2,3 M. P. Oxley,1 S. Okamoto,1 M. K (Received 10 February 2010; published 19 August 2010) Epitaxial oxide interfaces with broken translational-cell-by-unit-cell mapping of lattice parameters and oxygen octahedral rotations across the BiFeO3-La0:7Sr0:3MnO3 interface

  7. Two phase coexistence for the hydrogen-helium mixture

    E-Print Network [OSTI]

    Fantoni, Riccardo

    2015-01-01

    We use our newly constructed quantum Gibbs ensemble Monte Carlo algorithm to perform computer experiments for the two phase coexistence of a hydrogen-helium mixture. Our results are in quantitative agreement with the experimental results of C. M. Sneed, W. B. Streett, R. E. Sonntag, and G. J. Van Wylen. The difference between our results and the experimental ones is in all cases less than 15% relative to the experiment, reducing to less than 5% in the low helium concentration phase. At the gravitational inversion between the vapor and the liquid phase, at low temperatures and high pressures, the quantum effects become relevant. At extremely low temperature and pressure the first component to show superfluidity is the helium in the vapor phase.

  8. Evaluation of the Vaporization, Fusion, and Sublimation Enthalpies of the 1-Alkanols: The Vaporization Enthalpy of 1-, 6-, 7-, and 9-Heptadecanol,

    E-Print Network [OSTI]

    Chickos, James S.

    thermochemical cycles involving sublimation, fusion, and vaporization enthalpies.5 The technique is also capableEvaluation of the Vaporization, Fusion, and Sublimation Enthalpies of the 1-Alkanols: The Vaporization Enthalpy of 1-, 6-, 7-, and 9-Heptadecanol, 1-Octadecanol, 1-Eicosanol, 1-Docosanol, 1-Hexacosanol

  9. The correlation of epitaxial graphene properties and morphology of SiC (0001)

    SciTech Connect (OSTI)

    Guo, Y.; Guo, L. W., E-mail: lwguo@iphy.ac.cn, E-mail: xlchen@iphy.ac.cn; Huang, J.; Jia, Y. P.; Lin, J. J.; Lu, W.; Li, Z. L. [Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Yang, R. [Nanoscale Physics and Devices Laboratory, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Chen, X. L., E-mail: lwguo@iphy.ac.cn, E-mail: xlchen@iphy.ac.cn [Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100190 (China)

    2014-01-28

    The electronic properties of epitaxial graphene (EG) on SiC (0001) depend sensitively on the surface morphology of SiC substrate. Here, 2–3 layers of graphene were grown on on-axis 6H-SiC with different step densities realized through controlling growth temperature and ambient pressure. We show that epitaxial graphene on SiC (0001) with low step density and straight step edge possesses fewer point defects laying mostly on step edges and higher carrier mobility. A relationship between step density and EG mobility is established. The linear scan of Raman spectra combined with the atomic force microscopy morphology images revealed that the Raman fingerprint peaks are nearly the same on terraces, but shift significantly while cross step edges, suggesting the graphene is not homogeneous in strain and carrier concentration over terraces and step edges of substrates. Thus, control morphology of epitaxial graphene on SiC (0001) is a simple and effective method to pursue optimal route for high quality graphene and will be helpful to prepare wafer sized graphene for device applications.

  10. Energy band alignment of atomic layer deposited HfO{sub 2} on epitaxial (110)Ge grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-04

    The band alignment properties of atomic layer HfO{sub 2} film deposited on epitaxial (110)Ge, grown by molecular beam epitaxy, was investigated using x-ray photoelectron spectroscopy. The cross-sectional transmission electron microscopy exhibited a sharp interface between the (110)Ge epilayer and the HfO{sub 2} film. The measured valence band offset value of HfO{sub 2} relative to (110)Ge was 2.28 {+-} 0.05 eV. The extracted conduction band offset value was 2.66 {+-} 0.1 eV using the bandgaps of HfO{sub 2} of 5.61 eV and Ge bandgap of 0.67 eV. These band offset parameters and the interface chemical properties of HfO{sub 2}/(110)Ge system are of tremendous importance for the design of future high hole mobility and low-power Ge-based metal-oxide transistor devices.

  11. Drying of pulverized material with heated condensible vapor

    DOE Patents [OSTI]

    Carlson, Larry W. (Oswego, IL)

    1986-01-01

    Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fins, on the outer lateral surface thereof. The cooled collection fins are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized material then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal.

  12. Drying of pulverized material with heated condensible vapor

    DOE Patents [OSTI]

    Carlson, L.W.

    1984-08-16

    Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fines, on the outer lateral surface thereof. The cooled collection fines are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized materials then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal. 2 figs.

  13. Direct Real-Time Detection of Vapors from Explosive Compounds

    SciTech Connect (OSTI)

    Ewing, Robert G.; Clowers, Brian H.; Atkinson, David A.

    2013-10-03

    The real-time detection of vapors from low volatility explosives including PETN, tetryl, RDX and nitroglycerine along with various compositions containing these substances is demonstrated. This was accomplished with an atmospheric flow tube (AFT) using a non-radioactive ionization source and coupled to a mass spectrometer. Direct vapor detection was demonstrated in less than 5 seconds at ambient temperature without sample pre-concentration. The several seconds of residence time of analytes in the AFT provides a significant opportunity for reactant ions to interact with analyte vapors to achieve ionization. This extended reaction time, combined with the selective ionization using the nitrate reactant ions (NO3- and NO3-•HNO3), enables highly sensitive explosives detection. Observed signals from diluted explosive vapors indicate detection limits below 10 ppqv using selected ion monitoring (SIM) of the explosive-nitrate adduct at m/z 349, 378, 284 and 289 for tetryl, PETN, RDX and NG respectively. Also provided is a demonstration of the vapor detection from 10 different energetic formulations, including double base propellants, plastic explosives and commercial blasting explosives using SIM for the NG, PETN and RDX product ions.

  14. Vapor etching of nuclear tracks in dielectric materials

    DOE Patents [OSTI]

    Musket, Ronald G. (Danville, CA); Porter, John D. (Berkeley, CA); Yoshiyama, James M. (Fremont, CA); Contolini, Robert J. (Lake Oswego, OR)

    2000-01-01

    A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.

  15. Laser absorption spectroscopy system for vaporization process characterization and control

    SciTech Connect (OSTI)

    Galkowski, J.; Hagans, K.

    1993-09-07

    In support of the Lawrence Livermore National Laboratory`s (LLNL`s) Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) Program, a laser atomic absorption spectroscopy (LAS) system has been developed. This multi-laser system is capable of simultaneously measuring the line densities of {sup 238}U ground and metastable states, {sup 235}U ground and metastable states, iron, and ions at up to nine locations within the separator vessel. Supporting enrichment experiments that last over one hundred hours, this laser spectroscopy system is employed to diagnose and optimize separator system performance, control the electron beam vaporizer and metal feed systems, and provide physics data for the validation of computer models. As a tool for spectroscopic research, vapor plume characterization, vapor deposition monitoring, and vaporizer development, LLNL`s LAS laboratory with its six argon-ion-pumped ring dye lasers and recently added Ti:Sapphire and external-cavity diode-lasers has capabilities far beyond the requirements of its primary mission.

  16. Low temperature photochemical vapor deposition of alloy and mixed metal oxide films

    DOE Patents [OSTI]

    Liu, David K. (San Pablo, CA)

    1992-01-01

    Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor vapor(s) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor vapor(s) is formed by vaporization of one or more precursor materials, where the vaporization temperature(s) is selected to control the ratio of concentration of metals present in the precursor vapor(s) and/or the total precursor vapor pressure.

  17. Liu UCD Phy9B 07 12 17-6. Phase Change: Latent Heat

    E-Print Network [OSTI]

    Yoo, S. J. Ben

    Liu UCD Phy9B 07 12 17-6. Phase Change: Latent Heat GasLiquidSolid onVaporizatiFusion Phase of fusion LF Absorbs leasesRe Solid Liquid Absorbs leasesRe Liquid Gas heat of vaporization LV Latent in fluids: liquids & gases. Forced convection: circulation by pump/blower Natural convection: natural

  18. Removal of Sarin Aerosol and Vapor by Water Sprays

    SciTech Connect (OSTI)

    Brockmann, John E.

    1998-09-01

    Falling water drops can collect particles and soluble or reactive vapor from the gas through which they fall. Rain is known to remove particles and vapors by the process of rainout. Water sprays can be used to remove radioactive aerosol from the atmosphere of a nuclear reactor containment building. There is a potential for water sprays to be used as a mitigation technique to remove chemical or bio- logical agents from the air. This paper is a quick-look at water spray removal. It is not definitive but rather provides a reasonable basic model for particle and gas removal and presents an example calcu- lation of sarin removal from a BART station. This work ~ a starting point and the results indicate that further modeling and exploration of additional mechanisms for particle and vapor removal may prove beneficial.

  19. The effects of heat conduction on the vaporization of liquid invading superheated permeable rock

    SciTech Connect (OSTI)

    Woods, Andrew, W.; Fitzgerald, Shaun D.

    1996-01-24

    We examine the role of conductive and convective heat transfer in the vaporization of liquid as it slowly invades a superheated permeable rock. For very slow migration, virtually all of the liquid vaporizes. As the liquid supply rate increases beyond the rate of heat transfer by thermal conduction, a decreasing fraction of the liquid can vaporize. Indeed, for sufficiently high flow rates, the fraction vaporizing depends solely on the superheat of the rock, and any heat transfer from the superheated region is negligible. These results complement earlier studies of vaporization under very high injection rates, in which case the dynamic vapour pressure reduces the mass fraction vaporizing to very small values.

  20. Metamorphosis: Phases of UF{sub 6}

    SciTech Connect (OSTI)

    Dyer, R.H. [Department of Energy, Oak Ridge, TN (United States)

    1991-12-31

    A 15-minute videotape is presented. The subject matter is 150 grams of UF{sub 6} sealed in a glass tube. Close-up views show the UF{sub 6} as phase changes are effected by the addition or removal of heat from the closed system. The solid-to-liquid transition is shown as heat is added, both slowly and rapidly. The solid phases which result from freezing and from desublimation are contrasted. In the solid state, uranium hexafluoride is a nearly-white, dense crystalline solid. The appearance of this solid depends on whether it is formed by freezing from the liquid or by desublimation from the vapor phase. If frozen from the liquid, the solid particles take the form of irregularly shaped coarse grains, while the solid product of desublimation tends to be a rather formless mass without individually distinguishable particles. The changes in state are presented in terms of the UF{sub 6} phase diagram.

  1. Epitaxial Ni{sub 3}FeN thin films: A candidate for spintronic devices and magnetic sensors

    SciTech Connect (OSTI)

    Loloee, Reza

    2012-07-15

    A new type of epitaxial ferromagnetic nitride (Ni{sub 3} Fe N = permalloy nitride = 'PyN') compound films were grown on Al{sub 2}O{sub 3}(1120) substrates using reactive triode magnetron sputtering. The results of electron back-scattering diffraction and x-ray diffraction techniques indicate a high quality epitaxial crystalline structure with growth normal of (100). Magnetization measurements of epitaxial PyN films revealed several unique results. (1) A textbook square hysteresis loop that suggest existence of single magnetic domain in these films. (2) A coercive field is tunable from a few mOe up to a few Oe by changing the film thickness. (3) A magnetization that switches (rotate) over a very small field range of {delta}H{sub C} {<=} 0.05 Oe, independent of the film thickness. This small {delta}H indicates a very large resistive sensitivity ({delta}R/{delta}H) of the epitaxial PyN. (4) The epitaxial PyN thermal cycling through several cycles between '2 and 800 K' (-271 Degree-Sign C to +527 Degree-Sign C) shows much less degradation only about 2-5% compared to 40% degradation of a simple Py film. Four-probe transport measurements give an anisotropic magnetoresistance of Almost-Equal-To 6%, sufficiently higher than other known ferromagnetic materials. These interesting properties are ideal for a variety of spintronic devices and magnetic sensors.

  2. Effect of chemical order on the magnetic and electronic properties of epitaxial off-stoichiometry F e x S i 1 - x thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Karel, J.; Juraszek, J.; Minar, J.; Bordel, C.; Stone, K. H.; Zhang, Y. N.; Hu, J.; Wu, R. Q.; Ebert, H.; Kortright, J. B.; Hellman, F.

    2015-04-01

    Off-stoichiometry, epitaxial FexSi1-x thin films (0.5phase, while both theoretical and experimental results show that the magnetization is nearly the same in the B2 and D0? phases, meaning partial chemical disorder does not influence the magnetism. The dependencies of the magnetic moments are directly and nonlinearly linked to the number of Si atoms, primarily nearest neighbor but also to a lesser extent (up to 10%) next nearest neighbor, surrounding Fe, explaining the similarities between B2 and D0? and the strong enhancement for the A2 structure. The calculated electronic density of states shows many similarities in both structure and spin polarization between the D0? and B2 structures, while the A2 structure exhibits disorder broadening and a reduced spin polarization.

  3. ZnO:Sb/ZnO:Ga Light Emitting Diode on c-Plane Sapphire by Molecular Beam Epitaxy Zheng Yang, Sheng Chu, Winnie V. Chen1

    E-Print Network [OSTI]

    Yang, Zheng

    ZnO:Sb/ZnO:Ga Light Emitting Diode on c-Plane Sapphire by Molecular Beam Epitaxy Zheng Yang, Sheng substrates using plasma-assisted molecular-beam epitaxy. Mesa geometry light emitting diodes (LEDs) were demonstrated in recent years, such as photodetectors,8,9) light-emitting diodes (LEDs),10­13) and random lasing

  4. Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor Deposition

    E-Print Network [OSTI]

    Blanc, Wilfried; Nguyen, Luan; Bhaktha, S N B; Sebbah, Patrick; Pal, Bishnu P; Dussardier, Bernard

    2011-01-01

    Rare earth (RE) doped silica-based optical fibers with transparent glass ceramic (TGC) core was fabricated through the well-known modified chemical vapor deposition (MCVD) process without going through the commonly used stage of post-ceramming. The main characteristics of the RE-doped oxyde nanoparticles namely, their density and mean diameter in the fibers are dictated by the concentration of alkaline earth element used as phase separating agent. Magnesium and erbium co-doped fibers were fabricated. Optical transmission in term of loss due to scattering as well as some spectroscopic characteristics of the erbium ions was studied. For low Mg content, nano-scale particles could be grown with and relatively low scattering losses were obtained, whereas large Mg-content causes the growth of larger particles resulting in much higher loss. However in the latter case, certain interesting alteration of the spectroscopic properties of the erbium ions were observed. These initial studies should be useful in incorporati...

  5. Reduction of erythema in hairless guinea pigs after cutaneous sulfur mustard vapor exposure by pretreatment with niacinamide, promethazine and indomethacin

    SciTech Connect (OSTI)

    Yourick, J.J.; Dawson, J.S.; Mitcheltree, L.W.

    1995-12-31

    Erythema is the initial symptom that occurs after sulfur mustard (HD) cutaneous exposure. The time course of HD-induced erythema is similar to that observed after UV irradiation, which can be reduced by indomethacin. Sulfur mustard lethality is decreased by using promethazine, which is an antihistamine. Niacinamide can reduce microvesication after HD vapor exposure in hairless guinea pig (HGP) skin. The present study examines the effect of the combined administration of niacinamide, indomethacin and promethazine used alone or in all possible combinations on the degree of erythema and histopathologic skin damage after HD exposure in HGP. Niacinamide (750 mg kg%`, i.p.), promethazine (12.5 mg kg%1, i.m.) or indomethacin (4 mg kg%1, p.o.) used singly or in combination was given as a 30-min pretreatment before an 8-min HD vapor cup skin exposure. Using a combination pretreatment of niacinamide, promethazine and indomethacin, erythema was reduced at 4 (91%) and 6 (55%) h, but not 24 h after HD. The incidence of histopathological skin changes (microvesicles, follicular involvement, epidermal necrosis, intracellular edema and pustular epidermatitis) 24 h after HD was not reduced. This study indicates that HD (induced erythema) may result from several different mechanisms, including inflammation, histamine release and DNA damage. It is suggested that two phases of inflammation may occur: an early phase sensitive to antihistamines and non-steroidal antiinflammatory drugs and a late phase of extensive cell damage that was not sensitive to these drug pretreatments.

  6. A combined droplet train and ambient pressure photoemission spectrometer for the investigation of liquid/vapor interfaces

    E-Print Network [OSTI]

    Starr, David E.

    2008-01-01

    ambient conditions the vapor pressure of water or aqueousrange (e.g. , the equilibrium vapor pressure of water at itsUHV conditions due to the vapor pressure of the liquids, but

  7. The Atomic Vapor Laser Isotope Separation Program. [Atomic Vapor Laser Isotope Separation (AVLIS) Program

    SciTech Connect (OSTI)

    Not Available

    1992-11-09

    This report provides the finding and recommendations on the audit of the Atomic Vapor Laser Isotope Separation (AVLIS) program. The status of the program was assessed to determine whether the Department was achieving objectives stated in its January 1990 Plan for the Demonstration, Transition and Deployment of AVLIS Technology. Through Fiscal Year 1991, the Department had spent about $1.1 billion to develop AVLIS technology. The January 1990 plan provided for AVLIS to be far enough along by September to enable the Department to make a determination of the technical and economic feasibility of deployment. However, the milestones needed to support that determination were not met. An estimated $550 million would be needed to complete AVLIS engineering development and related testing prior to deployment. The earliest possible deployment date has slipped to beyond the year 2000. It is recommended that the Department reassess the requirement for AVLIS in light of program delays and changes that have taken place in the enrichment market since January 1990. Following the reassessment, a decision should be made to either fully support and promote the actions needed to complete AVLIS development or discontinue support for the program entirely. Management's position is that the Department will successfully complete the AVLIS technology demonstration and that the program should continue until it can be transferred to a Government corporation. Although the auditors recognize that AVLIS may be transferred, there are enough technical and financial uncertainties that a thorough assessment is warranted.

  8. Epitaxial single-crystal thin films of MnxTi1-xO2-? grown on (rutile)TiO2 substrates with pulsed laser deposition: Experiment and theory

    SciTech Connect (OSTI)

    Ilton, Eugene S.; Droubay, Timothy C.; Chaka, Anne M.; Kovarik, Libor; Varga, Tamas; Arey, Bruce W.; Kerisit, Sebastien N.

    2015-02-01

    Epitaxial rutile-structured single-crystal MnxTi1-xO2-? films were synthesized on rutile- (110) and -(001) substrates using pulsed laser deposition. The films were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and aberration-corrected transmission electron microscopy (ACTEM). Under the present conditions, 400oC and PO2 = 20 mTorr, single crystal epitaxial thin films were grown for x = 0.13, where x is the nominal average mole fraction of Mn. In fact, arbitrarily thick films could be grown with near invariant Mn/Ti concentration profiles from the substrate/film interface to the film surface. In contrast, at x = 0.25, Mn became enriched towards the surface and a secondary nano-scale phase formed which appeared to maintain the basic rutile structure but with enhanced z-contrast in the tunnels, or tetrahedral interstitial sites. Ab initio thermodynamic calculations provided quantitative estimates for the destabilizing effect of expanding the ?-MnO2 lattice parameters to those of TiO2-rutile, the stabilizing effect of diluting Mn with increasing Ti concentration, and competing reaction pathways.

  9. Microstructure of Co/X (X=Cu,Ag,Au) epitaxial thin films grown on Al{sub 2}O{sub 3}(0001) substrates

    SciTech Connect (OSTI)

    Ohtake, Mitsuru; Akita, Yuta; Futamoto, Masaaki; Kirino, Fumiyoshi

    2007-05-01

    Epitaxial thin films of Co/X (X=Cu,Ag,Au) were prepared on Al{sub 2}O{sub 3}(0001) substrates at substrate temperatures of 100 and 300 degree sign C by UHV molecular beam epitaxy. A complicated microstructure was realized for the epitaxial thin films. In-situ reflection high-energy electron diffraction observation has shown that X atoms of the buffer layer segregated to the surface during Co layer deposition, and it yielded a unique epitaxial granular structure. The structure consists of small Co grains buried in the X buffer layer, where both the magnetic small Co grains and the nonmagnetic X layer are epitaxially grown on the single crystal substrate. The structure varied depending on the X element and the substrate temperature. The crystal structure of Co grains is influenced by the buffer layer material and determined to be hcp and fcc structures for the buffer layer materials of Au and Cu, respectively.

  10. Solubilities of butane, vapor pressures, and densities for benzene + cyclohexane, benzene + methanol, and methanol + cyclohexane solutions at 298 K

    SciTech Connect (OSTI)

    Miyano, Yoshimori (Okayama Univ. of Science (Japan)); Hayduk, W. (Univ. of Ottawa, Ontario (Canada))

    1993-04-01

    In this paper the solubilities of butane at a pressure of 101.3 kPa and a temperature of 298.15 K are presented for three mixed solvent solutions: benzene + methanol, cyclohexane + methanol, and benzene + cyclohexane. The densities and vapor pressures are also reported for these solutions at the same conditions. Whereas the benzene + methanol and cyclohexane + methanol mixtures form azeotropic solutions, they are mutually soluble for all compositions of the two solvents. On the other hand, mixtures of cyclohexane and methanol are not mutually soluble but form two immiscible liquid phases for a significant portion of the composition range, but at a higher temperature also form an azeotropic solution.

  11. Slow light in paraffin-coated Rb vapor cells

    E-Print Network [OSTI]

    M. Klein; I. Novikova; D. F. Phillips; R. L. Walsworth

    2006-02-15

    We present preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapor cells, and describe the construction and testing of such cells. The slow ground state decoherence rate allowed by coated cell walls leads to a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (cell systems.

  12. Compositional Variations in Vapor Deposited Samarium Zirconate Coatings

    E-Print Network [OSTI]

    Wadley, Haydn

    Compositional Variations in Vapor Deposited Samarium Zirconate Coatings A Thesis Presented temperatures instead have relied on the development of thermal barrier coating (TBC) systems. The thermal barrier coating systems applied to superalloys consist of three layers: (i) an aluminum rich metallic bond

  13. Method for removing metal vapor from gas streams

    DOE Patents [OSTI]

    Ahluwalia, R.K.; Im, K.H.

    1996-04-02

    A process for cleaning an inert gas contaminated with a metallic vapor, such as cadmium, involves withdrawing gas containing the metallic contaminant from a gas atmosphere of high purity argon; passing the gas containing the metallic contaminant to a mass transfer unit having a plurality of hot gas channels separated by a plurality of coolant gas channels; cooling the contaminated gas as it flows upward through the mass transfer unit to cause contaminated gas vapor to condense on the gas channel walls; regenerating the gas channels of the mass transfer unit; and, returning the cleaned gas to the gas atmosphere of high purity argon. The condensing of the contaminant-containing vapor occurs while suppressing contaminant particulate formation, and is promoted by providing a sufficient amount of surface area in the mass transfer unit to cause the vapor to condense and relieve supersaturation buildup such that contaminant particulates are not formed. Condensation of the contaminant is prevented on supply and return lines in which the contaminant containing gas is withdrawn and returned from and to the electrorefiner and mass transfer unit by heating and insulating the supply and return lines. 13 figs.

  14. Chemical vapor deposition of fluorine-doped zinc oxide

    DOE Patents [OSTI]

    Gordon, Roy G. (Cambridge, MA); Kramer, Keith (Avon Lake, OH); Liang, Haifan (Santa Clara, CA)

    2000-06-06

    Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

  15. AN IMPROVED METHOD FOR TRANSFERRING GRAPHENE GROWN BY CHEMICAL VAPOR

    E-Print Network [OSTI]

    AN IMPROVED METHOD FOR TRANSFERRING GRAPHENE GROWN BY CHEMICAL VAPOR DEPOSITION YUJIE REN Key Laboratory of Semiconductor Materials and Applications Xiamen University, Xiamen 361005, P. R In this paper, we report an improved transfer of graphene by directly picking up the graphene with target

  16. Vapor deposited samarium zirconate thermal barrier coatings Hengbei Zhao a,

    E-Print Network [OSTI]

    Wadley, Haydn

    by Elsevier B.V. 1. Introduction Thermal barrier coating (TBC) systems have become an enabling materials technology for the gas turbine engines used for propulsion and power generation [1]. Through their abilityVapor deposited samarium zirconate thermal barrier coatings Hengbei Zhao a, , Carlos G. Levi b

  17. On the physical adsorption of vapors by microporous carbons

    SciTech Connect (OSTI)

    Bradley, R.H. (Univ. of Technology, Loughborough (United Kingdom). Inst. of Surface Science and Technology); Rand, B. (Univ. of Leeds (United Kingdom). Division of Ceramics)

    1995-01-01

    The physical adsorption of nonpolar and polar vapors by active carbons is discussed in relation to pore structure and pore wall chemistry. For nonpolar vapors the Dubinin-Radushkevich equation is used to derive micropore volumes (W[sub 0]), average adsorption energies (E[sub 0]), and micropore widths (L) for a number of systems. These parameters are used to interpret the adsorption behavior of nitrogen which, because it is a relatively small molecule, is frequently used at 77 K to probe porosity and surface area. Results are presented for three carbons from differing precursors, namely, coal, coconut shells, and polyvinylidene chloride (PVDC) to illustrate the applicability of the technique. For the latter carbon increases in micropore size, induced by activation in carbon dioxide, and reductions in accessible pore volume caused by heat treatment in argon are also characterized and related to structural changes. The approach is then extended to the adsorption of larger hydrogen vapors, where the resulting W[sub 0] values may require correction for molecular packing effects which occur in the lower relative pressure regions of the isotherms, i.e., during the filling of ultramicropores. These packing effects are shown to limit the use of the Polanyi characteristic curve for correlating isotherm data for several vapors, of differing molecular size, by one adsorbent. Data for the adsorption of water, which is a strongly polar liquid, have been interpreted using the Dubinin-Serpinsky equation.

  18. Sorption and Diffusion of Organic Vapors in Two Fluoroelastomers

    E-Print Network [OSTI]

    Wang, Ping

    ; fluoroelastomers; self-diffusion coefficient; in- teraction parameters; barrier properties INTRODUCTION FluorelSorption and Diffusion of Organic Vapors in Two Fluoroelastomers PING WANG,* NATHANIEL S. SCHNEIDER and Aflas are two fluoroelastomers designed to provide superior solvent resistance and, in the case

  19. Experimental Study of Water Vapor Adsorption on Geothermal

    E-Print Network [OSTI]

    Stanford University

    SGP-TR-148 Experimental Study of Water Vapor Adsorption on Geothermal Reservoir Rocks Shubo Shang Geothermal Program under Department of Energy Grant No. DE-FG07-90IDI2934,and by the Department of Petroleum Engineering, Stanford University Stanford Geothermal Program Interdisciplinary Research in Engineering

  20. Amine functionalization by initiated chemical vapor deposition (iCVD) for interfacial adhesion and film cohesion

    E-Print Network [OSTI]

    Xu, Jingjing, Ph. D. Massachusetts Institute of Technology

    2011-01-01

    Amine functional polymer thin films provide a versatile platform for subsequent functionalization because of their diverse reactivity. Initiated chemical vapor deposition (iCVD) is a polymer chemical vapor deposition ...

  1. M. Bahrami ENSC 461 (S 11) Assignment 8 1 Assignment #8 (Vapor Power Cycles)

    E-Print Network [OSTI]

    Bahrami, Majid

    M. Bahrami ENSC 461 (S 11) Assignment 8 1 ENSC 461 Assignment #8 (Vapor Power Cycles) Assignment date: Due date: Consider a reheat-regenerative vapor power cycle with two feedwater heaters, a closed

  2. Simulation and Validation of Vapor Compression System Faults and Start-up/Shut-down Transients 

    E-Print Network [OSTI]

    Ayyagari, Balakrishna

    2012-10-19

    as vapor compression system faults. This thesis addresses these concerns and enhances the existing modeling library to capture the transients related to the above mentioned conditions. In this thesis, the various faults occurring in a vapor compressor...

  3. Technology Solutions Case Study: Moisture Durability of Vapor Permeable Insulating Sheathing

    SciTech Connect (OSTI)

    2013-10-01

    In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor permeable insulation on retrofit walls with vapor permeable cavity insulation. Retrofit strategies are a key factor in reducing exterior building stock consumption.

  4. Water Vapor Variability Across Spatial Scales: Insights for Theory, Parameterization, and Model Assessment

    E-Print Network [OSTI]

    Pressel, Kyle Gregory

    2012-01-01

    11 2 Scaling of Water Vapor Structure Functions as 2.1cloud model. q is the total water mixing-ratio and q ? isAIRS Exponents from AIRS Data Water Vapor Time Series from a

  5. Method and apparatus to measure vapor pressure in a flow system

    DOE Patents [OSTI]

    Grossman, Mark W. (Belmont, MA); Biblarz, Oscar (Swampscott, MA)

    1991-01-01

    The present invention is directed to a method for determining, by a condensation method, the vapor pressure of a material with a known vapor pressure versus temperature characteristic, in a flow system particularly in a mercury isotope enrichment process.

  6. Synthesis of multiferroic Er-Fe-O thin films by atomic layer and chemical vapor deposition

    SciTech Connect (OSTI)

    Mantovan, R., E-mail: roberto.mantovan@mdm.imm.cnr.it; Vangelista, S.; Wiemer, C.; Lamperti, A.; Tallarida, G. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Chikoidze, E.; Dumont, Y. [GEMaC, Université de Versailles St. Quentin en Yvelines-CNRS, Versailles (France); Fanciulli, M. [Laboratorio MDM IMM-CNR, I-20864 Agrate Brianza (MB) (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Milano (Italy)

    2014-05-07

    R-Fe-O (R?=?rare earth) compounds have recently attracted high interest as potential new multiferroic materials. Here, we report a method based on the solid-state reaction between Er{sub 2}O{sub 3} and Fe layers, respectively grown by atomic layer deposition and chemical vapor deposition, to synthesize Er-Fe-O thin films. The reaction is induced by thermal annealing and evolution of the formed phases is followed by in situ grazing incidence X-ray diffraction. Dominant ErFeO{sub 3} and ErFe{sub 2}O{sub 4} phases develop following subsequent thermal annealing processes at 850?°C in air and N{sub 2}. Structural, chemical, and morphological characterization of the layers are conducted through X-ray diffraction and reflectivity, time-of-flight secondary ion-mass spectrometry, and atomic force microscopy. Magnetic properties are evaluated by magnetic force microscopy, conversion electron Mössbauer spectroscopy, and vibrating sample magnetometer, being consistent with the presence of the phases identified by X-ray diffraction. Our results constitute a first step toward the use of cost-effective chemical methods for the synthesis of this class of multiferroic thin films.

  7. Phase Transitions

    E-Print Network [OSTI]

    Michael Creutz

    1997-08-25

    This is a set of notes on phase transitions and critical phenomena prepared to accompany my lectures for the RHIC '97 summer school, held at Brookhaven from July 6 to 16, 1997.

  8. Optimising GaN (1122) hetero-epitaxial templates grown on (1010) sapphire

    E-Print Network [OSTI]

    Pristovsek, Markus; Frentrup, Martin; Han, Yisong; Humphreys, Colin J.

    2015-01-01

    N (112¯2) hetero-epitaxial templates grown on (101¯0) sapphire process was monitored with a two wavelength Laytec EpiTT reflectometer. Two different approaches have been used for the initial GaN buffer. One is a nucleation of GaN islands which were... annealed and overgrown. This approach is described in [2]. The other approach is AlN nucle- ation, which is performed at 5 kPa reactor pressure with a total flow of 21.7 litres/minute. First the re- actor is heated to 1060?C under hydrogen flow and 150 Pa...

  9. Structural and optoelectronic properties of germanium-rich islands grown on silicon using molecular beam epitaxy

    SciTech Connect (OSTI)

    Nataraj, L.; Sustersic, N.; Coppinger, M.; Gerlein, L. F.; Kolodzey, J. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Cloutier, S. G. [Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716 (United States); Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19711 (United States)

    2010-03-22

    We report on the structural and optoelectronic properties of self-assembled germanium-rich islands grown on silicon using molecular beam epitaxy. Raman, photocurrent, photoluminescence, and transient optical spectroscopy measurements suggest significant built-in strains and a well-defined interface with little intermixing between the islands and the silicon. The shape of these islands depends on the growth conditions and includes pyramid, dome, barn-shaped, and superdome islands. Most importantly, we demonstrate that these germanium-rich islands provide efficient light emission at telecommunication wavelengths on a complementary metal-oxide semiconductor-compatible platform.

  10. Growth of atomically smooth MgO films on graphene by molecular beam epitaxy

    SciTech Connect (OSTI)

    Wang, W. H.; Han, W.; Pi, K.; McCreary, K. M.; Miao, F.; Bao, W.; Lau, C. N.; Kawakami, R. K.

    2008-11-03

    We investigate the growth of MgO films on graphene by molecular beam epitaxy and find that surface diffusion promotes a rough morphology. To reduce the mobility of surface atoms, the graphene surface is dressed by Ti atoms prior to MgO deposition. With as little as 0.5 ML (monolayer) of Ti, the MgO overlayer becomes atomically smooth. Furthermore, no aggregation of MgO is observed at the edges of the graphene sheet. These results are important for the fabrication of nanoscale electronic and spintronic devices.

  11. Interface Coupling Transition in a Thin EpitaxialAntiferromagnetic Film Interacting with a Ferromagnetic Substrate

    SciTech Connect (OSTI)

    Finazzi, M.; Brambilla, A.; Biagioni, P.; Graf, J.; Gweon, G.-H.; Scholl, A.; Lanzara, A.; Duo, L.

    2006-09-07

    We report experimental evidence for a transition in theinterface coupling between an antiferromagnetic film and a ferromagneticsubstrate. The transition is observed in a thin epitaxial NiO film grownon top of Fe(001) as the film thickness is increased. Photoemissionelectron microscopy excited with linearly polarized x rays shows that theNiO film is antiferromagnetic at room temperature with in-plane uniaxialmagnetic anisotropy. The anisotropy axis is perpendicular to the Fesubstrate magnetization when the NiO thickness is less than about 15A,but rapidly becomes parallel to the Fe magnetization for a NiO coveragehigher than 25 A.

  12. Effect of Oxygen Adsorption on the Local Properties of Epitaxial Graphene on SiC (0001)

    E-Print Network [OSTI]

    Mathieu, C; Mentes, T O; Pallecchi, E; Locatelli, A; Latil, S; Belkhou, R; Ouerghi, A

    2015-01-01

    The effect of oxygen adsorption on the local structure and electronic properties of monolayer graphene grown on SiC(0001) has been studied by means of Low Energy Electron Microscopy (LEEM), microprobe Low Energy Electron Diffraction (\\muLEED) and microprobe Angle Resolved Photoemission (\\muARPES). We show that the buffer layer of epitaxial graphene on SiC(0001) is partially decoupled after oxidation. The monitoring of the oxidation process demonstrates that the oxygen saturates the Si dangling bonds, breaks some Si-C bonds at the interface and intercalates the graphene layer. Accurate control over the oxidation parameters enables us to tune the charge density modulation in the layer.

  13. Comparison of beryllium oxide and pyrolytic graphite crucibles for boron doped silicon epitaxy

    SciTech Connect (OSTI)

    Ali, Dyan; Richardson, Christopher J. K. [Laboratory for Physical Sciences, University of Maryland, College Park, Maryland 20740 (United States)

    2012-11-15

    This article reports on the comparison of beryllium oxide and pyrolytic graphite as crucible liners in a high-temperature effusion cell used for boron doping in silicon grown by molecular beam epitaxy. Secondary ion mass spectroscopy analysis indicates decomposition of the beryllium oxide liner, leading to significant incorporation of beryllium and oxygen in the grown films. The resulting films are of poor crystal quality with rough surfaces and broad x-ray diffraction peaks. Alternatively, the use of pyrolytic graphite crucible liners results in higher quality films.

  14. Structural characterization of metastable hcp-Ni thin films epitaxially grown on Au(100) single-crystal underlayers

    SciTech Connect (OSTI)

    Ohtake, Mitsuru; Tanaka, Takahiro; Futamoto, Masaaki; Kirino, Fumiyoshi

    2010-05-15

    Ni(1120) epitaxial thin films with hcp structure were prepared on Au(100) single-crystal underlayers at 100 deg. C by ultra high vacuum molecular beam epitaxy. The detailed film structure is studied by in situ reflection high energy electron diffraction, x-ray diffraction, and transmission electron microscopy. The hcp-Ni film consists of two types of variants whose c-axes are rotated around the film normal by 90 deg. each other. An atomically sharp boundary is recognized between the film and the underlayer, where misfit dislocations are introduced. Presence of such dislocations seems to relieve the strain caused by the lattice mismatch between the film and the underlayer.

  15. Influence of process variables on electron beam chemical vapor deposition of platinum

    E-Print Network [OSTI]

    Wang, Zhong L.

    Influence of process variables on electron beam chemical vapor deposition of platinum D. Beaulieu; accepted 8 August 2005; published 22 September 2005 Electron beam chemical vapor deposition was performed. DOI: 10.1116/1.2050672 I. INTRODUCTION Electron beam chemical vapor deposition EBCVD is a technology

  16. Optical characterization of InN layers grown by high-pressure chemical vapor deposition

    E-Print Network [OSTI]

    Dietz, Nikolaus

    Optical characterization of InN layers grown by high-pressure chemical vapor deposition M. Alevli properties of InN layers grown by high-pressure chemical vapor deposition have been studied. Raman, infrared at elevated temperatures, a high-pressure chemical vapor deposition HPCVD system has been established at GSU.6

  17. Correlation Between Opacity and Surface Water Vapor Pressure Measurements at Rio Frio

    E-Print Network [OSTI]

    Groppi, Christopher

    Correlation Between Opacity and Surface Water Vapor Pressure Measurements at Rio Frio M.A. Holdaway 1, 1996 Abstract We use the surface water vapor pressure measured by weather stations at 4060 m opacity. The surface water vapor pressure is inverted some 20% of the time at night and some 35

  18. Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical vapor deposition

    E-Print Network [OSTI]

    Dietz, Nikolaus

    grown by high-pressure chemical vapor deposition have been studied. Atomic hydrogen cleaning produced and heterostructures--which can be accomplished by low- pressure metalorganic chemical vapor deposition MOCVD --the- rium vapor pressure of nitrogen during growth. This requires different approaches in growing structures

  19. A HOMOGENIZATION TECHNIQUE FOR THE BOLTZMANN EQUATION FOR LOW PRESSURE CHEMICAL VAPOR DEPOSITION 1

    E-Print Network [OSTI]

    Markowich, Peter A.

    A HOMOGENIZATION TECHNIQUE FOR THE BOLTZMANN EQUATION FOR LOW PRESSURE CHEMICAL VAPOR DEPOSITION 1 the approach. The setup models low pressure chemical vapor deposition processes in the manufacturing. Low pressure chemical vapor deposition is used in the manufactur- ing of integrated circuits

  20. Effect of Substrate Roughness on D Spacing Supports Theoretical Resolution of Vapor Pressure Paradox

    E-Print Network [OSTI]

    Nagle, John F.

    Effect of Substrate Roughness on D Spacing Supports Theoretical Resolution of Vapor Pressure with and provides experimental support for a recently proposed theoretical resolution of the vapor pressure paradox has been called the vapor pressure paradox (Rand and Parsegian, 1989). Resolving this paradox