National Library of Energy BETA

Sample records for bi uup se

  1. Bi-Se doped with Cu, p-type semiconductor

    DOE Patents [OSTI]

    Bhattacharya, Raghu Nath; Phok, Sovannary; Parilla, Philip Anthony

    2013-08-20

    A Bi--Se doped with Cu, p-type semiconductor, preferably used as an absorber material in a photovoltaic device. Preferably the semiconductor has at least 20 molar percent Cu. In a preferred embodiment, the semiconductor comprises at least 28 molar percent of Cu. In one embodiment, the semiconductor comprises a molar percentage of Cu and Bi whereby the molar percentage of Cu divided by the molar percentage of Bi is greater than 1.2. In a preferred embodiment, the semiconductor is manufactured as a thin film having a thickness less than 600 nm.

  2. Structural phase transitions in Bi2Se3 under high pressure

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

    Yu, Zhenhai; Gu, Genda; Wang, Lin; Hu, Qingyang; Zhao, Jinggeng; Yan, Shuai; Yang, Ke; Sinogeikin, Stanislav; Mao, Ho -kwang

    2015-11-02

    Raman spectroscopy and angle dispersive X-ray diffraction (XRD) experiments of bismuth selenide (Bi2Se3) have been carried out to pressures of 35.6 and 81.2 GPa, respectively, to explore its pressure-induced phase transformation. The experiments indicate that a progressive structural evolution occurs from an ambient rhombohedra phase (Space group (SG): R-3m) to monoclinic phase (SG: C2/m) and eventually to a high pressure body-centered tetragonal phase (SG: I4/mmm). Evidenced by our XRD data up to 81.2 GPa, the Bi2Se3 crystallizes into body-centered tetragonal structures rather than the recently reported disordered body-centered cubic (BCC) phase. Furthermore, first principles theoretical calculations favor the viewpoint thatmore » the I4/mmm phase Bi2Se3 can be stabilized under high pressure (>30 GPa). Remarkably, the Raman spectra of Bi2Se3 from this work (two independent runs) are still Raman active up to ~35 GPa. Furthermore, it is worthy to note that the disordered BCC phase at 27.8 GPa is not observed here. The remarkable difference in atomic radii of Bi and Se in Bi2Se3 may explain why Bi2Se3 shows different structural behavior than isocompounds Bi2Te3 and Sb2Te3.« less

  3. Potential thermoelectric performance from optimization of hole-doped Bi2Se3

    SciTech Connect (OSTI)

    Parker, David S; Singh, David J

    2011-01-01

    We present an analysis of the potential thermoelectric performance of hole-doped Bi2Se3, which is commonly considered to show inferior room temperature performance when compared to Bi2Te3. We find that if the lattice thermal conductivity can be reduced by nanostructuring techniques (as have been applied to Bi2Te3) the material may show optimized ZT values of unity or more in the 300 - 500 K temperature range and thus be suitable for cooling and moderate temperature waste heat recovery and thermoelectric solar cell applications. Central to this conclusion are the larger band gap and the relatively heavier valence bands of Bi2Se3.

  4. Electronic structure, irreversibility line and magnetoresistance of Cu0.3Bi2Se3 superconductor

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

    Hemian, Yi; Gu, Genda; Chen, Chao -Yu; Sun, Xuan; Xie, Zhuo -Jin; Feng, Ya; Liang, Ai -Ji; Peng, Ying -Ying; He, Shao -Long; Zhao, Lin; et al

    2015-06-01

    CuxBi2Se3 is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the CuxBi2Se3 superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi2Se3 topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ~4000 Oe formore » the Cu0.3Bi2Se3 superconductor with a middle point Tc of 1.9K. The relation between the upper critical field Hc2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu0.3Bi2Se3 superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.« less

  5. A comparative transport study of Bi{sub 2}Se{sub 3} and Bi{sub 2}Se{sub 3}/yttrium iron garnet

    SciTech Connect (OSTI)

    Jiang, Zilong; Tang, Chi; Shi, Jing; Katmis, Ferhat; Wei, Peng; Moodera, Jagadeesh S.

    2014-06-02

    Bilayers of 20 quintuple layer Bi{sub 2}Se{sub 3} on 30 nm thick yttrium iron garnet (YIG) have been grown with molecular beam epitaxy in conjunction with pulsed laser deposition. The presence of the ferri-magnetic insulator YIG causes additional scattering to the surface states of the Bi{sub 2}Se{sub 3} topological insulator layer, as indicated by the temperature dependence of the resistivity. From the two-channel analysis of the Hall data, we find that the surface contribution in the bilayer samples is greatly reduced. Furthermore, the weak antilocalization effect from the surface states is clearly suppressed due to the presence of the YIG layer.

  6. Tuning thermoelectricity in a Bi2Se3 topological insulator via varied film thickness

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

    Guo, Minghua; Wang, Zhenyu; Xu, Yong; Huang, Huaqing; Zang, Yunyi; Liu, Chang; Duan, Wenhui; Gan, Zhongxue; Zhang, Shou-Cheng; He, Ke; et al

    2016-01-12

    We report thermoelectric transport studies on Bi2Se3 topological insulator thin films with varied thickness grown by molecular beam epitaxy. We find that the Seebeck coefficient and thermoelectric power factor decrease systematically with the reduction of film thickness. These experimental observations can be explained quantitatively by theoretical calculations based on realistic electronic band structure of the Bi2Se3 thin films. Lastly, this work illustrates the crucial role played by the topological surface states on the thermoelectric transport of topological insulators, and sheds new light on further improvement of their thermoelectric performance.

  7. Molecular beam epitaxial growth of Bi{sub 2}Se{sub 3} nanowires and nanoflakes

    SciTech Connect (OSTI)

    Knebl, G. M. Gessler, J. R.; Kamp, M.; Höfling, S.

    2014-09-29

    Topological Insulators are in focus of immense research efforts and rapid scientific progress is obtained in that field. Bi{sub 2}Se{sub 3} has proven to be a topological insulator material that provides a large band gap and a band structure with a single Dirac cone at the Γ-point. This makes Bi{sub 2}Se{sub 3} one of the most promising three dimensional topological insulator materials. While Bi{sub 2}Se{sub 3} nanowires and nanoflakes so far were fabricated with different methods and for different purposes, we here present the first Bi{sub 2}Se{sub 3} nanowires as well as nanoflakes grown by molecular beam epitaxy. The nanostructures were nucleated on pretreated, silicon (100) wafers. Altering the growth conditions nanoflakes could be fabricated instead of nanowires; both with high crystalline quality, confirmed by scanning electron microscopy as well as transmission electron microscopy. These nanostructures have promise for spintronic devices and Majorana fermion observation in contact to superconductor materials.

  8. The new misfit compound (BiSe){sub 1.15}(TiSe{sub 2}){sub 2} and the role of dimensionality in the Cu{sub x}(BiSe){sub 1+δ}(TiSe{sub 2}){sub n} series

    SciTech Connect (OSTI)

    Trump, Benjamin A.; Livi, Kenneth J.T.; McQueen, Tyrel M.

    2014-01-15

    The synthesis and physical properties of the new misfit compound (BiSe){sub 1.15}(TiSe{sub 2}){sub 2} are reported. Transmission electron microscopy and powder X-ray diffraction show that the structure consists of alternating rock-salt type BiSe layers and hexagonal (TiSe{sub 2}){sub 2} double layers. Resistivity, specific heat, and magnetization measurements show that it has metallic and diamagnetic behaviors. These results are interpreted and discussed in the context of the transition between single-layer (BiSe){sub 1.13}(TiSe{sub 2}), which shows no charge density wave, and infinite-layered (bulk) 1T-TiSe{sub 2}, which undergoes a charge density wave transition at T=202 K. Intercalation with copper, Cu{sub x}(BiSe){sub 1.15}(TiSe{sub 2}){sub 2}, (0≤x≤0.10) is also reported, but unlike Cu{sub x}TiSe{sub 2}, no superconductivity is observed down to T=0.05 K. Thus, the series Cu{sub x}(BiSe){sub 1+δ}(TiSe{sub 2}){sub n} provides an effective approach to elucidate the impact of dimensionality on charge density wave formation and superconductivity. - Graphical abstract: The newly discovered misfit compound (BiSe){sub 1.15}(TiSe{sub 2}){sub 2} shown in the series (BiSe){sub 1+δ}(TiSe{sub 2}){sub n}. Display Omitted - Highlights: • Reports the structure and properties of the new misfit compound (BiSe){sub 1.15}(TiSe{sub 2}){sub 2}. • The structure consists of a rock salt type BiSe layer and a double (TiSe{sub 2}){sub 2} layer. • The n=1, 2 misfits (BiSe){sub 1+δ}(TiSe{sub 2}){sub n} are found not to exhibit CDW transitions. • Evidence is presented that there is likely a low-lying CDW excited state. • The series Cu{sub x}(BiSe){sub 1+δ}(TiSe{sub 2}){sub 2} does not superconduct, unlike Cu{sub x}TiSe{sub 2}.

  9. Structural phase transitions in Bi2Se3 under high pressure

    SciTech Connect (OSTI)

    Yu, Zhenhai; Gu, Genda; Wang, Lin; Hu, Qingyang; Zhao, Jinggeng; Yan, Shuai; Yang, Ke; Sinogeikin, Stanislav; Mao, Ho -kwang

    2015-11-02

    Raman spectroscopy and angle dispersive X-ray diffraction (XRD) experiments of bismuth selenide (Bi2Se3) have been carried out to pressures of 35.6 and 81.2 GPa, respectively, to explore its pressure-induced phase transformation. The experiments indicate that a progressive structural evolution occurs from an ambient rhombohedra phase (Space group (SG): R-3m) to monoclinic phase (SG: C2/m) and eventually to a high pressure body-centered tetragonal phase (SG: I4/mmm). Evidenced by our XRD data up to 81.2 GPa, the Bi2Se3 crystallizes into body-centered tetragonal structures rather than the recently reported disordered body-centered cubic (BCC) phase. Furthermore, first principles theoretical calculations favor the viewpoint that the I4/mmm phase Bi2Se3 can be stabilized under high pressure (>30 GPa). Remarkably, the Raman spectra of Bi2Se3 from this work (two independent runs) are still Raman active up to ~35 GPa. Furthermore, it is worthy to note that the disordered BCC phase at 27.8 GPa is not observed here. The remarkable difference in atomic radii of Bi and Se in Bi2Se3 may explain why Bi2Se3 shows different structural behavior than isocompounds Bi2Te3 and Sb2Te3.

  10. Experimental study of the valence band of Bi2Se3

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

    Gao, Yi-Bin; He, Bin; Parker, David; Androulakis, Ioannis; Heremans, Joseph P.

    2014-09-26

    The valence band of Bi2Se3 is investigated with Shubnikov - de Haas measurements, galvanomagnetic and thermoelectric transport. At low hole concentration, the hole Fermi surface is closed and box-like, but at higher concentrations it develops tube-like extensions that are open. The experimentally determined density-of-states effective mass is lighter than density-functional theory calculations predict; while we cannot give a definitive explanation for this, we suspect that the theory may lack sufficient precision to compute room-temperature transport properties, such as the Seebeck coefficient, in solids in which there are Van der Waals interlayer bonds.

  11. Dependence of superconductivity in CuxBi?Se? on quenching conditions

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

    Schneeloch, J. A.; Zhong, R. D.; Xu, Z. J.; Gu, G. D.; Tranquada, J. M.

    2015-04-20

    Topological superconductivity, implying gapless protected surface states, has recently been proposed to exist in the compound CuxBi?Se?. Unfortunately, low diamagnetic shielding fractions and considerable inhomogeneity have been reported in this compound. In an attempt to understand and improve on the finite superconducting volume fractions, we have investigated the effects of various growth and post-annealing conditions. With a melt-growth (MG) method, diamagnetic shielding fractions of up to 56% in Cu???Bi?Se? have been obtained, the highest value reported for this method. We investigate the efficacy of various quenching and annealing conditions, finding that quenching from temperatures above 560C is essential for superconductivity,morewhereas quenching from lower temperatures or not quenching at all is detrimental. A modified floating zone (FZ) method yielded large single crystals but little superconductivity. Even after annealing and quenching, FZ-grown samples had much less chance of being superconducting than MG-grown samples. From the low shielding fractions in FZ-grown samples and the quenching dependence, we suggest that a metastable secondary phase having a small volume fraction in most of the samples may be responsible for the superconductivity.less

  12. Benefits of Carrier-Pocket Anisotropy to Thermoelectric Performance: The Case of p -Type AgBiSe2

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

    Parker, David S.; May, Andrew F.; Singh, David J.

    2015-06-05

    Here we study theoretically the effects of anisotropy on the thermoelectric performance of p-type AgBiSe2. We present an apparent realization of the thermoelectric benefits of one-dimensional plate-like carrier pocket anisotropy in the valence band of this material. Based on first principles calculations we find a substantial anisotropy in the electronic structure, likely favorable for thermoelectric performance, in the valence bands of the hexagonal phase of the silver chalcogenide thermoelectric AgBiSe2, while the conduction bands are more isotropic, and in our experiments do not attain high performance. AgBiSe2 has already exhibited a ZT value of 1.5 in a high-temperature disordered fccmore » phase, but room-temperature performance has not been demonstrated. We develop a theory for the ability of anisotropy to decouple the density-of-states and conductivity effective masses, pointing out the influence of this effect in the high performance thermoelectrics Bi2Te3 and PbTe. From our first principles and Boltzmann transport calculations we find that p-type AgBiSe2 has substantial promise as a room temperature thermoelectric, and estimate its performance.« less

  13. Benefits of Carrier Pocket Anisotropy to Thermoelectric Performance: The case of p-type AgBiSe2

    SciTech Connect (OSTI)

    Parker, David S; May, Andrew F; Singh, David J

    2015-01-01

    We study theoretically the effects of anisotropy on the thermoelectric performance of p-type AgBiSe2. We present an apparent realization of the thermoelectric benefits of one-dimensional plate-like carrier pocket anisotropy in the valence band of this material. Based on first principles calculations we find a substantial anisotropy in the electronic structure, likely favorable for thermoelectric performance, in the valence bands of the hexagonal phase of the silver chalcogenide thermoelectric AgBiSe2, while the conduction bands are more isotropic, and in our experiments do not attain high performance. AgBiSe2 has already exhibited a ZT value of 1.5 in a high-temperature disordered fcc phase, but room-temperature performance has not been demonstrated. We develop a theory for the ability of anisotropy to decouple the density-of-states and conductivity effective masses, pointing out the influence of this effect in the high performance thermoelectrics Bi2Te3 and PbTe. From our first principles and Boltzmann transport calculations we find that p-type AgBiSe2 has substantial promise as a room temperature thermoelectric, and estimate its performance.

  14. Fano q-reversal in topological insulator Bi2Se3

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

    S. V. Dordevic; Petrovic, C.; Foster, G. M.; Wolf, M. S.; Stojilovic, N.; Lei, Hechang; Chen, Z.; Li, Z. Q.; Tung, L. C.

    2016-03-22

    Here, we studied the magneto-optical response of a canonical topological insulator Bi2Se3 with the goal of addressing a controversial issue of electron–phonon coupling. Magnetic-field induced modifications of reflectance are very pronounced in the infrared part of the spectrum, indicating strong electron–phonon coupling. This coupling causes an asymmetric line-shape of the 60 cm–1 phonon mode, and is analyzed within the Fano formalism. The analysis reveals that the Fano asymmetry parameter (q) changes sign when the cyclotron resonance is degenerate with the phonon mode. To the best of our knowledge this is the first example of magnetic field driven q-reversal.

  15. Time-resolved terahertz dynamics in thin films of the topological insulator Bi2Se3

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

    Valdés Aguilar, R.; Qi, J.; Brahlek, M.; Bansal, N.; Azad, A.; Bowlan, J.; Oh, S.; Taylor, A. J.; Prasankumar, R. P.; Yarotski, D. A.

    2015-01-07

    We use optical pump–THz probe spectroscopy at low temperatures to study the hot carrier response in thin Bi2Se3 films of several thicknesses, allowing us to separate the bulk from the surface transient response. We find that for thinner films the photoexcitation changes the transport scattering rate and reduces the THz conductivity, which relaxes within 10 picoseconds (ps). For thicker films, the conductivity increases upon photoexcitation and scales with increasing both the film thickness and the optical fluence, with a decay time of approximately 5 ps as well as a much higher scattering rate. Furthermore, these different dynamics are attributed tomore » the surface and bulk electrons, respectively, and demonstrate that long-lived mobile surface photo-carriers can be accessed independently below certain film thicknesses for possible optoelectronic applications.« less

  16. Connecting thermoelectric performance and topological-insulator behavior: Bi2Te3 and Bi2Te2Se from first principles

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

    Shi, Hongliang; Parker, David S.; Du, Mao-Hua; Singh, David J.

    2015-01-20

    Thermoelectric performance is of interest for numerous applications such as waste-heat recovery and solid-state energy conversion and will be seen to be closely connected to topological-insulator behavior. In this paper, we here report first-principles transport and defect calculations for Bi2Te2Se in relation to Bi2Te3. The two compounds are found to contain remarkably different electronic structures in spite of being isostructural and isoelectronic. We also discuss these results in terms of the topological-insulator characteristics of these compounds.

  17. Temperature dependent Raman scattering studies of three dimensional topological insulators Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Irfan, Bushra; Chatterjee, Ratnamala; Sahoo, Satyaprakash; Gaur, Anand P. S.; Ahmadi, Majid; Katiyar, Ram S.; Guinel, Maxime J.-F.

    2014-05-07

    We investigate the temperature dependent (83 K≤T≤523 K) frequency shift of 2A{sub g}{sup 1} and 1E{sub g}{sup 2} phonon modes in the three dimensional topological insulator Bi{sub 2}Se{sub 3}, using Raman spectroscopy. The high quality single crystals of Bi{sub 2}Se{sub 3} were grown using a modified Bridgman technique and characterized by Laue diffraction and high resolution transmission electron microscopy. A significant broadening in the line shape and red-shift in the frequencies were observed with increase in temperature. Polarized Raman scattering measurement shows a strong polarization effect of A{sub g}{sup 1} and A{sub g}{sup 2} phonon modes which confirms the good quality single crystals of Bi{sub 2}Se{sub 3}. Temperature co-efficient for A{sub 1g}{sup 1}, E{sub g}{sup 2}, and A{sub 1g}{sup 2} modes was estimated to be −1.44 × 10{sup −2}, −1.94 × 10{sup −2}, and −1.95 × 10{sup −2} cm{sup −1}∕K, respectively. Our results shed light on anharmonic properties of Bi{sub 2}Se{sub 3}.

  18. Electronic structure of a superconducting topological insulator Sr-doped Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Han, C. Q.; Chen, W. J.; Zhu, Fengfeng; Yao, Meng-Yu; Li, H.; Li, Z. J.; Wang, M.; Gao, Bo F.; Guan, D. D.; Liu, Canhua; Qian, Dong Jia, Jin-Feng; Gao, C. L.

    2015-10-26

    Using high-resolution angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy, the atomic and low energy electronic structure of the Sr-doped superconducting topological insulators (Sr{sub x}Bi{sub 2}Se{sub 3}) was studied. Scanning tunneling microscopy shows that most of the Sr atoms are not in the van der Waals gap. After Sr doping, the Fermi level was found to move further upwards when compared with the parent compound Bi{sub 2}Se{sub 3}, which is consistent with the low carrier density in this system. The topological surface state was clearly observed, and the position of the Dirac point was determined in all doped samples. The surface state is well separated from the bulk conduction bands in the momentum space. The persistence of separated topological surface state combined with small Fermi energy makes this superconducting material a very promising candidate for the time reversal invariant topological superconductor.

  19. Antiferromagnetic order induced by gadolinium substitution in Bi{sub 2}Se{sub 3} single crystals

    SciTech Connect (OSTI)

    Kim, S. W.; Jung, M. H.; Vrtnik, S.; Dolinšek, J.

    2015-06-22

    Magnetic topological insulators can serve as a fundamental platform for various spin-based device applications. We report the antiferromagnetic order induced by the magnetic impurity dopants of Gd in Gd{sub x}Bi{sub 2−x}Se{sub 3} and the systematic results with varying the Gd concentration x ( = 0.14, 0.20, 0.30, and 0.40). The antiferromagnetic order is demonstrated by the magnetic susceptibility, electrical resistivity, and specific heat measurements. The anomaly observed at T{sub N} = 6 K for x ≥ 0.30 shifts towards lower temperature with increasing the magnetic field, indicative of antiferromagnetic ground state. The Gd substitution into Bi{sub 2}Se{sub 3} enables not only tuning the magnetism from paramagnetic to antiferromagnetic for high x (≥ 0.30) but also giving a promising candidate for antiferromagnetic topological insulators.

  20. Tunable inverse topological heterostructure utilizing (Bi1−xInx)2Se3 and multichannel weak-antilocalization effect

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

    Brahlek, Matthew J.; Koirala, Nikesh; Liu, Jianpeng; Yusufaly, Tahir I.; Salehi, Maryam; Han, Myung-Geun; Zhu, Yimei; Vanderbilt, David; Oh, Seongshik

    2016-03-10

    In typical topological insulator (TI) systems the TI is bordered by a non-TI insulator, and the surrounding conventional insulators, including vacuum, are not generally treated as part of the TI system. Here, we implement a material system where the roles are reversed, and the topological surface states form around the non-TI (instead of the TI) layers. This is realized by growing a layer of the tunable non-TI (Bi1-xInx)2Se3 in between two layers of the TI Bi2Se3 using the atomically precise molecular beam epitaxy technique. On this tunable inverse topological platform, we systematically vary the thickness and the composition of themore » (Bi1-xInx)2Se3 layer and show that this tunes the coupling between the TI layers from strongly coupled metallic to weakly coupled, and finally to a fully decoupled insulating regime. This system can be used to probe the fundamental nature of coupling in TI materials and provides a tunable insulating layer for TI devices.« less

  1. Acoustic phonon dynamics in thin-films of the topological insulator Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2015-04-28

    Transient reflectivity traces measured for nanometer-sized films (6–40 nm) of the topological insulator Bi{sub 2}Se{sub 3} revealed GHz-range oscillations driven within the relaxation of hot carriers photoexcited with ultrashort (∼100 fs) laser pulses of 1.51 eV photon energy. These oscillations have been suggested to result from acoustic phonon dynamics, including coherent longitudinal acoustic phonons in the form of standing acoustic waves. An increase of oscillation frequency from ∼35 to ∼70 GHz with decreasing film thickness from 40 to 15 nm was attributed to the interplay between two different regimes employing traveling-acoustic-waves for films thicker than 40 nm and the film bulk acoustic wave resonator (FBAWR) modes for films thinner than 40 nm. The amplitude of oscillations decays rapidly for films below 15 nm thick when the indirect intersurface coupling in Bi{sub 2}Se{sub 3} films switches the FBAWR regime to that of the Lamb wave excitation. The frequency range of coherent longitudinal acoustic phonons is in good agreement with elastic properties of Bi{sub 2}Se{sub 3}.

  2. 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 semiconductorTI 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.

  3. Palladium site ordering and the occurrence of superconductivity in Bi{sub 2}Pd{sub 3}Se{sub 2-x}S{sub x}

    SciTech Connect (OSTI)

    Weihrich, R.; Matar, S.F.; Anusca, I.; Pielnhofer, F.; Peter, P.; Bachhuber, F.; Eyert, V.

    2011-04-15

    The crystallographic and electronic structures of compounds related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}) are investigated with respect to the recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. Similarities and differences of the crystal structures are discussed within the series of solid solutions Bi{sub 2}Pd{sub 3}S{sub 2-x}Se{sub x} from powder and single crystal diffraction data. From crystal structure refinements, the question of different structures and settings of parkerite is discussed. Similar and different 2D and 3D partial Pd-Ch (Ch=S, Se) structures are related to half antiperovskite ordering schemes. To investigate the relation of low dimensional structures and the occurrence of superconductivity, electronic structures are analyzed by scalar-relativistic DFT calculations, including site projected DOS, ECOV and Fermi surfaces. -- Graphical abstract: Structure relations for perovskite type BiPd{sub 3}C, BiPd{sub 3/2}Se and BiPd{sub 3/2}S. Display Omitted Research highlights: {yields} Merging crystallographic and electronic structures studies to understand chalcogenides related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}). {yields} Investigation in view of recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. {yields} Relationship of half perovskites with perovskites.

  4. Surface collective modes in the topological insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex

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

    Kogar, A.; Gu, G.; Vig, S.; Thaler, A.; Wong, M. H.; Xiao, Y.; Reig-i-Plessis, D.; Cho, G. Y.; Valla, T.; Pan, Z.; et al

    2015-12-15

    In this study, we used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex. Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ''(q,ω) at THz energy scales, and is the most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggestsmore » that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role.« less

  5. Effect of sintering in ball-milled K{sub 2}Bi{sub 8}Se{sub 13} thermoelectric nano-composites

    SciTech Connect (OSTI)

    Hatzikraniotis, E.; Ioannou, M.; Chrissafis, K.; Chung, D.Y.; Paraskevopoulos, K.M.; Kyratsi, Th.

    2012-09-15

    K{sub 2}Bi{sub 8}Se{sub 13} has many attractive features for thermoelectric applications. Recently, K{sub 2}Bi{sub 8}Se{sub 13}-based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated based on powder technology techniques. The Seebeck coefficient has been enhanced while the thermal conductivity has been decreased presenting, thus, interesting behavior. The behavior of the materials under heat treatment conditions is now of interest, as the application of sintering process is necessary for the development of thermoelectric modules. In this work, the crystallization of the K{sub 2}Bi{sub 8}Se{sub 13}-based nano-composites is studied using Differential Scanning Calorimetry. The results show that crystallization follows a multiple-step process with different activation energies. The thermoelectric properties are also discussed in the range that crystallization occurs. - Graphical Abstract: {beta}-K{sub 2}Bi{sub 8}Se{sub 13}-based nanocomposites follow a multiple-step crystallization process. Highlights: Black-Right-Pointing-Pointer K{sub 2}Bi{sub 8}Se{sub 13}-based composites consisting of nanocrystalline and amorphous phases. Black-Right-Pointing-Pointer Sintering results multiple-step crystallization with variable activation energies. Black-Right-Pointing-Pointer Thermoelectric properties follow a step-like behavior during sintering. Black-Right-Pointing-Pointer Properties are attributed to the strain relaxation, nucleation and grain growth.

  6. Electronic structure, irreversibility line and magnetoresistance of Cu0.3Bi2Se3 superconductor

    SciTech Connect (OSTI)

    Hemian, Yi; Gu, Genda; Chen, Chao -Yu; Sun, Xuan; Xie, Zhuo -Jin; Feng, Ya; Liang, Ai -Ji; Peng, Ying -Ying; He, Shao -Long; Zhao, Lin; Liu, Guo -Dong; Dong, Xiao -Li; Zhang, Jun; Chen, Chuang -Tian; Xu, Zu -Yan; Zhou, X. -J.

    2015-06-01

    CuxBi2Se3 is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the CuxBi2Se3 superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi2Se3 topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ~4000 Oe for the Cu0.3Bi2Se3 superconductor with a middle point Tc of 1.9K. The relation between the upper critical field Hc2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu0.3Bi2Se3 superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.

  7. Temperature-dependent carrier–phonon coupling in topological insulator Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Lai, Yi-Ping; Liu, Jia-Ming; Chen, Hsueh-Ju; Wu, Kuang-Hsiung

    2014-12-08

    Temperature-dependent (11.0 K−294.5 K) carrier–phonon coupling in Bi{sub 2}Se{sub 3} is investigated by ultrafast pump−probe spectroscopy. The rise time of the differential reflectivity is interpreted by a combined effect of electron temperature relaxation and hot-phonon lifetime. The electron−phonon coupling constant of the bulk state (λ=0.63±0.05) is deduced from theoretical fitting. Increasing hot-phonon lifetime with decreasing temperature is attributed to a decreasing phonon−phonon collision rate. A complete analysis of the thermalization process is presented. Understanding carrier and phonon dynamics is essential for future optoelectronic and spintronic applications of topological insulators.

  8. Gate-modulated weak anti-localization and carrier trapping in individual Bi{sub 2}Se{sub 3} nanoribbons

    SciTech Connect (OSTI)

    Wang, Li-Xian; Yan, Yuan; Liao, Zhi-Min Yu, Da-Peng

    2015-02-09

    We report a gate-voltage modulation on the weak anti-localization of individual topological insulator Bi{sub 2}Se{sub 3} nanoribbons. The phase coherence length decreases with decreasing the carrier density of the surface states on the bottom surface of the Bi{sub 2}Se{sub 3} nanoribbon as tuning the gate voltage from 0 to −100 V, indicating that the electron-electron interaction dominates the decoherence at low carrier density. Furthermore, we observe an abnormal conductance decline at positive gate voltage regime, which is ascribed to the capture of surface carriers by the trapping centers in the surface oxidation layer.

  9. Connecting thermoelectric performance and topological-insulator behavior: Bi2Te3 and Bi2Te2Se from first principles

    SciTech Connect (OSTI)

    Shi, Hongliang; Parker, David S.; Du, Mao-Hua; Singh, David J.

    2015-01-20

    Thermoelectric performance is of interest for numerous applications such as waste-heat recovery and solid-state energy conversion and will be seen to be closely connected to topological-insulator behavior. In this paper, we here report first-principles transport and defect calculations for Bi2Te2Se in relation to Bi2Te3. The two compounds are found to contain remarkably different electronic structures in spite of being isostructural and isoelectronic. We also discuss these results in terms of the topological-insulator characteristics of these compounds.

  10. Anomalous reduction of the switching voltage of Bi-doped Ge{sub 0.5}Se{sub 0.5} ovonic threshold switching devices

    SciTech Connect (OSTI)

    Seo, Juhee; Ahn, Hyung-Woo; Shin, Sang-yeol; Cheong, Byung-ki; Lee, Suyoun

    2014-04-14

    Switching devices based on Ovonic Threshold Switching (OTS) have been considered as a solution to overcoming limitations of Si-based electronic devices, but the reduction of switching voltage is a major challenge. Here, we investigated the effect of Bi-doping in Ge{sub 0.5}Se{sub 0.5} thin films on their thermal, optical, electrical properties, as well as on the characteristics of OTS devices. As Bi increased, it was found that both of the optical energy gap (E{sub g}{sup opt}) and the depth of trap states decreased resulting in a drastic reduction of the threshold voltage (V{sub th}) by over 50%. In addition, E{sub g}{sup opt} was found to be about three times of the conduction activation energy for each composition. These results are explained in terms of the Mott delocalization effect by doping Bi.

  11. Comparison of crystal growth and thermoelectric properties of n-type Bi-Se-Te and p-type Bi-Sb-Te nanocrystalline thin films: Effects of homogeneous irradiation with an electron beam

    SciTech Connect (OSTI)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp; Imai, Kazuo; Uyama, Masato; Nishi, Yoshitake [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Hagino, Harutoshi; Miyazaki, Koji [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu 804-8550 (Japan); Tanaka, Saburo [Department of Mechanical Engineering, College of Engineering, Nihon University, Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)

    2014-06-07

    The effects of homogenous electron beam (EB) irradiation on the crystal growth and thermoelectric properties of n-type Bi-Se-Te and p-type Bi-Sb-Te thin films were investigated. Both types of thin films were prepared by flash evaporation, after which homogeneous EB irradiation was performed at an acceleration voltage of 0.17?MeV. For the n-type thin films, nanodots with a diameter of less than 10?nm were observed on the surface of rice-like nanostructures, and crystallization and crystal orientation were improved by EB irradiation. The resulting enhancement of mobility led to increased electrical conductivity and thermoelectric power factor for the n-type thin films. In contrast, the crystallization and crystal orientation of the p-type thin films were not influenced by EB irradiation. The carrier concentration increased and mobility decreased with increased EB irradiation dose, possibly because of the generation of defects. As a result, the thermoelectric power factor of p-type thin films was not improved by EB irradiation. The different crystallization behavior of the n-type and p-type thin films is attributed to atomic rearrangement during EB irradiation. Selenium in the n-type thin films is more likely to undergo atomic rearrangement than the other atoms present, so only the crystallinity of the n-type Bi-Se-Te thin films was enhanced.

  12. Optimum composition of a Bi{sub 2}Te{sub 3-x}Se{sub x} alloy for the n-type leg of a thermoelectric generator

    SciTech Connect (OSTI)

    Prokofieva, L. V. Pshenay-Severin, D. A.; Konstantinov, P. P.; Shabaldin, A. A.

    2009-08-15

    The reliability of determination of model parameters for the Bi{sub 2}Te{sub 3-x}Se{sub x} alloys is improved by extending the concentration and temperature ranges in experimental studies and, correspondingly, in calculations of kinetic coefficients based on the two-band model of the electronic spectrum. The obtained results served as a motivation for a study of the thermoelectric figure of merit for the above-mentioned alloys with x = 0.3, 0.45, and 0.6 and with the electron concentration varied in the range (1-50) x 10{sup 18} cm{sup -3} at temperatures 300-550 K. Comparison of the results showed that the highest efficiency is exhibited by the Bi{sub 2}Te{sub 2.7}Se{sub 0.3} alloy with the absolute value of the thermoelectric power of about 165 {mu}VK{sup -1} at 300 K, and the dimensionless efficiency is equal to 1.2 at 410 K. An appreciable decrease in thermal conductivity in alloys with x = 0.6 at 410 K is related to a larger band gap and could beneficially affect the figure of merit. However, the magnitude of this effect is found to be too small to compensate a decrease in electrical conductivity due to a large fraction of heavy electrons in the concentration and to a high content of selenium.

  13. Comparison of Sn-doped and nonstoichiometric vertical-Bridgman-grown crystals of the topological insulator Bi{sub 2}Te{sub 2}Se

    SciTech Connect (OSTI)

    Kushwaha, S. K. Gibson, Q. D.; Cava, R. J.; Xiong, J.; Ong, N. P.; Pletikosic, I.; Weber, A. P.; Fedorov, A. V.; Valla, T.

    2014-04-14

    A comparative study of the properties of topological insulator Bi{sub 2}Te{sub 2}Se (BTS) crystals grown by the vertical Bridgeman method is described. Two defect mechanisms that create acceptor impurities to compensate for the native n-type carriers are compared: Bi excess, and light Sn doping. Both methods yield low carrier concentrations and an n-p crossover over the length of the grown crystal boules, but lower carrier concentrations and higher resistivities are obtained for the Sn-doped crystals, which reach carrier concentrations as low as 8??10{sup 14}?cm{sup ?3}. Further, the temperature dependent resistivities for the Sn-doped crystals display strongly activated behavior at high temperatures, with a characteristic energy of half the bulk band gap. The (001) cleaved Sn-doped BTS crystals display high quality Shubnikov de Haas (SdH) quantum oscillations due to the topological surface state electrons. Angle resolved photoelectron spectroscopy (ARPES) characterization shows that the Fermi energy (E{sub F}) for the Sn-doped crystals falls cleanly in the surface states with no interference from the bulk bands, which the Dirac point for the surface states lies approximately 60?meV below the top of the bulk valence band maximum, and allows for a determination of the bulk and surface state carrier concentrations as a function of Energy near E{sub F}. Electronic structure calculations that compare Bi excess and Sn dopants in BTS demonstrate that Sn acts as a special impurity, with a localized impurity band that acts as a charge buffer occurring inside the bulk band gap. We propose that the special resonant level character of Sn in BTS gives rise to the exceptionally low carrier concentrations and activated resistivities observed.

  14. Effect of carrier recombination on ultrafast carrier dynamics in thin films of the topological insulator Bi{sub 2}Se{sub 3}

    SciTech Connect (OSTI)

    Glinka, Yuri D.; Babakiray, Sercan; Johnson, Trent A.; Holcomb, Mikel B.; Lederman, David

    2014-10-27

    Transient reflectivity (TR) from thin films (6–40 nm thick) of the topological insulator Bi{sub 2}Se{sub 3} revealed ultrafast carrier dynamics, which suggest the existence of both radiative and non-radiative recombination between electrons residing in the upper cone of initially unoccupied high energy Dirac surface states (SS) and holes residing in the lower cone of occupied low energy Dirac SS. The modeling of measured TR traces allowed us to conclude that recombination is induced by the depletion of bulk electrons in films below ∼20 nm thick due to the charge captured on the surface defects. We predict that such recombination processes can be observed using time-resolved photoluminescence techniques.

  15. Surface collective modes in the topological insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex

    SciTech Connect (OSTI)

    Kogar, A.; Gu, G.; Vig, S.; Thaler, A.; Wong, M. H.; Xiao, Y.; Reig-i-Plessis, D.; Cho, G. Y.; Valla, T.; Pan, Z.; Schneeloch, J.; Zhong, R.; Hughes, T. L.; MacDougall, G. J.; Chiang, T. -C.; Abbamonte, P.

    2015-12-15

    In this study, we used low-energy, momentum-resolved inelastic electron scattering to study surface collective modes of the three-dimensional topological insulators Bi2Se3 and Bi0.5Sb1.5Te3-xSex. Our goal was to identify the “spin plasmon” predicted by Raghu and co-workers [Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary collective mode is a surface plasmon arising from the bulk, free carriers in these materials. This excitation dominates the spectral weight in the bosonic function of the surface χ''(q,ω) at THz energy scales, and is the most likely origin of a quasiparticle dispersion kink observed in previous photoemission experiments. Our study suggests that the spin plasmon may mix with this other surface mode, calling for a more nuanced understanding of optical experiments in which the spin plasmon is reported to play a role.

  16. X-ray magnetic spectroscopy of MBE-grown Mn-doped Bi{sub 2}Se{sub 3} thin films

    SciTech Connect (OSTI)

    Collins-McIntyre, L. J.; Watson, M. D.; Zhang, S. L.; Coldea, A. I.; Hesjedal, T.; Baker, A. A.; Harrison, S. E.; Pushp, A.; Kellock, A. J.; Parkin, S. S. P.; Laan, G. van der

    2014-12-15

    We report the growth of Mn-doped Bi{sub 2}Se{sub 3} thin films by molecular beam epitaxy (MBE), investigated by x-ray diffraction (XRD), atomic force microscopy (AFM), SQUID magnetometry and x-ray magnetic circular dichroism (XMCD). Epitaxial films were deposited on c-plane sapphire substrates by co-evaporation. The films exhibit a spiral growth mechanism typical of this material class, as revealed by AFM. The XRD measurements demonstrate a good crystalline structure which is retained upon doping up to ?7.5 atomic-% Mn, determined by Rutherford backscattering spectrometry (RBS), and show no evidence of the formation of parasitic phases. However an increasing interstitial incorporation of Mn is observed with increasing doping concentration. A magnetic moment of 5.1 ?{sub B}/Mn is obtained from bulk-sensitive SQUID measurements, and a much lower moment of 1.6 ?{sub B}/Mn from surface-sensitive XMCD. At ?2.5 K, XMCD at the Mn L{sub 2,3} edge, reveals short-range magnetic order in the films and indicates ferromagnetic order below 1.5 K.

  17. Electron-phonon superconductivity in LaO{sub 0.5}F{sub 0.5}BiSe...

    Office of Scientific and Technical Information (OSTI)

    coupling for the newly discovered superconductor LaOsub 0.5Fsub 0.5BiSesub 2. ... 2, this compound is also a conventional electron-phonon coupling induced superconductor. ...

  18. Experimental study of the valence band of Bi2Se3

    SciTech Connect (OSTI)

    Gao, Yi-Bin; He, Bin; Parker, David; Androulakis, Ioannis; Heremans, Joseph P.

    2014-09-26

    The valence band of Bi2Se3 is investigated with Shubnikov - de Haas measurements, galvanomagnetic and thermoelectric transport. At low hole concentration, the hole Fermi surface is closed and box-like, but at higher concentrations it develops tube-like extensions that are open. The experimentally determined density-of-states effective mass is lighter than density-functional theory calculations predict; while we cannot give a definitive explanation for this, we suspect that the theory may lack sufficient precision to compute room-temperature transport properties, such as the Seebeck coefficient, in solids in which there are Van der Waals interlayer bonds.

  19. Structural, electrical, and thermoelectrical properties of (Bi{sub 1-x}Sb{sub x}){sub 2}Se{sub 3} alloys prepared by a conventional melting technique

    SciTech Connect (OSTI)

    Shokr, E. Kh.; Ibrahim, E. M. M. Abdel Hakeem, A. M.; Adam, A. M.

    2013-01-15

    Polycrystalline solid solutions of (Bi{sub 1-x}Sb{sub x}){sub 2}Se{sub 3} (x = 0, 0.025, 0.050, 0.075, 0.100) were prepared using a facile method based on the conventional melting technique followed by annealing process. X-ray analysis and Raman spectroscopical measurements revealed formation of Bi{sub 2}Se{sub 3} in single phase. The electrical and thermoelectric properties have been studied on the bulk samples in the temperature range 100-420 K. The electrical conductivity measurements show that the activation energy and room-temperature electrical conductivity dependences on the Sb content respectively exhibit minimum and maximum values at x = 0.05. The thermoelectric power exhibited a maximum value near the room temperature suggesting promising materials for room-temperature applications. The highest power factor value was found to be 13.53 {mu}W K{sup -2} cm{sup -1} and recorded for the x = 0.05 compound.

  20. Benefits of Carrier-Pocket Anisotropy to Thermoelectric Performance: The Case of p -Type AgBiSe2

    SciTech Connect (OSTI)

    Parker, David S.; May, Andrew F.; Singh, David J.

    2015-06-05

    Here we study theoretically the effects of anisotropy on the thermoelectric performance of p-type AgBiSe2. We present an apparent realization of the thermoelectric benefits of one-dimensional plate-like carrier pocket anisotropy in the valence band of this material. Based on first principles calculations we find a substantial anisotropy in the electronic structure, likely favorable for thermoelectric performance, in the valence bands of the hexagonal phase of the silver chalcogenide thermoelectric AgBiSe2, while the conduction bands are more isotropic, and in our experiments do not attain high performance. AgBiSe2 has already exhibited a ZT value of 1.5 in a high-temperature disordered fcc phase, but room-temperature performance has not been demonstrated. We develop a theory for the ability of anisotropy to decouple the density-of-states and conductivity effective masses, pointing out the influence of this effect in the high performance thermoelectrics Bi2Te3 and PbTe. From our first principles and Boltzmann transport calculations we find that p-type AgBiSe2 has substantial promise as a room temperature thermoelectric, and estimate its performance.

  1. CsBi4Te6: A High-Performance Thermoelectric Material for Low...

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

    thermoelectric properties of CsBi(4)Te(6) appear to match or exceed those of Bi(2-x)Sb(x)Te(3-y)Se(y) alloys. URL: Link to article - National Center for Biotechnology Information

  2. Bi-Weekly Reports 2014

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

    Waste Isolation Pilot Plant Hazardous Waste Facility Permit Number: NM4890139088-TSDF Jose R. FrancoCBFO and Robert L. McQuinnNWP dated September 5, 2014 Bi-Weekly Report as...

  3. Bi-stable optical actuator

    DOE Patents [OSTI]

    Holdener, Fred R.; Boyd, Robert D.

    2000-01-01

    The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.

  4. Site selectivity on chalcogen atoms in superconducting La(O,F)BiSSe

    SciTech Connect (OSTI)

    Tanaka, Masashi Matsushita, Yoshitaka; Fujioka, Masaya; Denholme, Saleem J.; Yamaguchi, Takahide; Takeya, Hiroyuki; Yamaki, Takuma; Takano, Yoshihiko

    2015-03-16

    Single crystals of La(O,F)BiSSe were grown by using a CsCl flux method. Single crystal X-ray structural analysis reveals that the crystal structure is isostructural to the BiS{sub 2}- or BiSe{sub 2}-based compounds crystallizing with space group P4/nmm (lattice parameters a = 4.1110(2) Å, c = 13.6010(7) Å). However, the S atoms are selectively occupied at the apical site of the Bi-SSe pyramids in the superconducting layer. The single crystals show a superconducting transition at around 4.2 K in the magnetic susceptibility and resistivity measurements. The superconducting anisotropic parameter is determined to be 34–35 from its upper critical magnetic field. The anisotropy is in the same range with that of other members of the La(O,F)BiCh{sub 2} (Ch = S, Se) family under ambient pressure.

  5. Midea: Order (2013-SE-1505)

    Broader source: Energy.gov [DOE]

    DOE ordered GD Midea Air-Conditioning Equipment Co. Ltd. to pay a $416,800 civil penalty after finding Midea had manufactured and distributed in commerce in the U.S. atleast 14,968 units of basic model MWJ1-08ERN1-BI8, a noncompliant room air conditioner.

  6. Materials Data on Ni3(BiSe)2 (SG:12) by Materials Project

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kristin Persson

    2015-02-09

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  7. Pb7Bi4Se13: A Lillianite Homologue with Promising Thermoelectric...

    Office of Scientific and Technical Information (OSTI)

    Subject: solar (photovoltaic), solar (thermal), phonons, thermal conductivity, thermoelectric, electrodes - solar, defects, charge transport, materials and chemistry by design, ...

  8. Materials Data on NaBiSe2 (SG:141) by Materials Project

    SciTech Connect (OSTI)

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  9. Dependence of superconductivity in CuxBi2Se3 on quenching conditions

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

    Schneeloch, J. A.; Zhong, R. D.; Xu, Z. J.; Gu, G. D.; Tranquada, J. M.

    2015-04-20

    Topological superconductivity, implying gapless protected surface states, has recently been proposed to exist in the compound CuxBi₂Se₃. Unfortunately, low diamagnetic shielding fractions and considerable inhomogeneity have been reported in this compound. In an attempt to understand and improve on the finite superconducting volume fractions, we have investigated the effects of various growth and post-annealing conditions. With a melt-growth (MG) method, diamagnetic shielding fractions of up to 56% in Cu₀̣₃Bi₂Se₃ have been obtained, the highest value reported for this method. We investigate the efficacy of various quenching and annealing conditions, finding that quenching from temperatures above 560°C is essential for superconductivity,more » whereas quenching from lower temperatures or not quenching at all is detrimental. A modified floating zone (FZ) method yielded large single crystals but little superconductivity. Even after annealing and quenching, FZ-grown samples had much less chance of being superconducting than MG-grown samples. Thus, from the low shielding fractions in FZ-grown samples and the quenching dependence, we suggest that a metastable secondary phase having a small volume fraction in most of the samples may be responsible for the superconductivity.« less

  10. Materials Data on Bi2(SeO3)3 (SG:14) by Materials Project

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  11. Materials Data on Bi2TeSe2 (SG:166) by Materials Project

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  12. Recent Advances in the Growth of Bi-Sb-Te-Se Thin Films

    SciTech Connect (OSTI)

    Wang, Guoyu; Endicott, Lynn; Uher, Ctirad

    2011-08-01

    Thin films of Bi₂Te₃, Sb₂Te₃ and Bi₂Se₃ have been intensively studied during the past ten years both as the best thermoelectric materials operating near room temperature and also as an excellent material with which to explore the newly-discovered form of quantum matter called topological insulators (TI). In this review, we first recapitulate the fundamental properties of bulk forms of these materials, then discuss recent progress in fabrication of thin films and superlattices of these narrowgap semiconductors, discuss their transport properties relevant to their effectiveness as thermoelectric materials, and finally give an outlook on this material system for both fundamental study and applications in thermoelectric energy conversion.

  13. Solon SE | Open Energy Information

    Open Energy Info (EERE)

    to: navigation, search Name: Solon SE Place: Berlin, Berlin, Germany Zip: D-12489 Sector: Solar Product: Manufacturer of PV modules and tracking systems, and integrator of solar...

  14. About-PHaSe-EFRC

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

    LGRT Conte Buildings The University of Massachusetts Amherst Energy Frontier Research Center (EFRC) - Polymer-Based Materials for Harvesting Solar Energy, PHaSE - was one of 46 ...

  15. Superconducting Bi2Te: Pressure-induced universality in the (Bi2)m(Bi2Te3)n series

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

    Stillwell, Ryan L.; Jeffries, Jason R.; Jenei, Zsolt; Weir, Samuel T.; Vohra, Yogesh K.

    2016-03-09

    Using high-pressure magnetotransport techniques we have discovered superconductivity in Bi2Te, a member of the infinitely adaptive (Bi2)m(Bi2Te3)n series, whose end members, Bi and Bi2Te3, can be tuned to display topological surface states or superconductivity. Bi2Te has a maximum Tc = 8.6 K at P = 14.5 GPa and goes through multiple high pressure phase transitions, ultimately collapsing into a bcc structure that suggests a universal behavior across the series. High-pressure magnetoresistance and Hall measurements suggest a semi-metal to metal transition near 5.4 GPa, which accompanies the hexagonal to intermediate phase transition seen via x-ray diffraction measurements. In addition, the linearitymore » of Hc2 (T) exceeds the Werthamer-Helfand-Hohenberg limit, even in the extreme spin-orbit scattering limit, yet is consistent with other strong spin-orbit materials. Furthermore, considering these results in combination with similar reports on strong spin-orbit scattering materials seen in the literature, we suggest the need for a new theory that can address the unconventional nature of their superconducting states.« less

  16. BiOctane | Open Energy Information

    Open Energy Info (EERE)

    Product: Biofuel start-up planning to design and develop a biodiesel and ethanol refinery. References: BiOctane1 This article is a stub. You can help OpenEI by expanding it....

  17. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO{sub 3} thin film

    SciTech Connect (OSTI)

    Gupta, Surbhi; Gupta, Vinay; Tomar, Monika; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

    2014-06-21

    Multiferroic Bismuth Ferrite (BiFeO{sub 3}) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO{sub 3} thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO{sub 3} and Fe{sub 2}O{sub 3} to pure BiFeO{sub 3} phase and, subsequently, to a mixture of BiFeO{sub 3} and Bi{sub 2}O{sub 3} with increase in the concentration of excess Bi from 0% to 15%. BiFeO{sub 3} thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe{sub 2}O{sub 3}). Deterioration in ferroic properties of BiFeO{sub 3} thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO{sub 3} thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm{sup 2} and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO{sub 3} thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO{sub 3} thin films exhibiting the improved multiferroic properties.

  18. Midea: Proposed Penalty (2013-SE-1505)

    Broader source: Energy.gov [DOE]

    DOE alleged in a Notice of Proposed Civil Penalty that GD Midea Air-Conditioning Equipment Co. Ltd. manufactured and distributed noncompliant room air conditioner basic model MWJ1-08ERN1-BI8 in the U.S.

  19. Superconductivity in strong spin orbital coupling compound Sb2Se3

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

    Kong, P. P.; Sun, F.; Xing, L. Y.; Zhu, J.; Zhang, S. J.; Li, W. M.; Liu, Q. Q.; Wang, X. C.; Feng, S. M.; Yu, X. H.; et al

    2014-10-20

    Recently, A2B3 type strong spin orbital coupling compounds such as Bi2Te3, Bi2Se3 and Sb2Te3 were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb2Se3 on the other hand was found to be topological trivial, but theoretical studies indicated that the pressure might induce Sb2Se3 into a topological nontrivial state. We report on the discovery of superconductivity in Sb2Se3 single crystal induced via pressure. Our experiments indicated that Sb2Se3 became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at ~3 GPa which should be related tomore » the topological quantum transition. The superconducting transition temperature (TC) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. As a result, high pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of TC slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.« less

  20. Resources-PHaSe-EFRC

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

    Resources This webpage is provided for legacy archive purposes only, as of 30 April 2015. However, the facilities and resources created under PHaSE (thanks to the support of the U.S. Department of Energy) remain available for their original purpose of investigating organic-based electronic materials. Resources As a national and regional center of excellence for energy research, PHaSE has access to many resources linked from the Department of Energy and the greater UMass Amherst campus, as well

  1. From thermoelectric bulk to nanomaterials: Current progress for Bi 2 Te 3 and CoSb 3: From thermoelectric bulk to nanomaterials

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

    Peranio, N.; Eibl, O.; Bäßler, S.; Nielsch, K.; Klobes, B.; Hermann, R. P.; Daniel, M.; Albrecht, M.; Görlitz, H.; Pacheco, V.; et al

    2015-10-29

    We synthesized Bi2Te3 and CoSb3 based nanomaterials and their thermoelectric, structural, and vibrational properties analyzed to assess and reduce ZT-limiting mechanisms. The same preparation and/or characterization methods were applied in the different materials systems. Single-crystalline, ternary p-type Bi15Sb29Te56, and n-type Bi38Te55Se7 nanowires with power factors comparable to nanostructured bulkmaterialswere prepared by potential-pulsed electrochemical deposition in a nanostructured Al2O3 matrix. p-type Sb2Te3, n-type Bi2Te3, and n-type CoSb3 thin films were grown at room temperature using molecular beam epitaxy and were subsequently annealed at elevated temperatures. It yielded polycrystalline, single phase thin films with optimized charge carrier densities. In CoSb3 thin filmsmore » the speed of sound could be reduced by filling the cage structure with Yb and alloying with Fe yielded p-type material. Bi2(Te0.91Se0.09)3/SiC and (Bi0.26Sb0.74)2Te3/SiC nanocomposites with low thermal conductivities and ZT values larger than 1 were prepared by spark plasma sintering. Nanostructure, texture, chemical composition, as well as electronic and phononic excitations were investigated by X-ray diffraction, nuclear resonance scattering, inelastic neutron scattering, M ossbauer spectroscopy, and transmission electron microscopy. Furthermore, for Bi2Te3 materials, ab-initio calculations together with equilibrium and non-equilibrium molecular dynamics simulations for point defects yielded their formation energies and their effect on lattice thermal conductivity, respectively. Current advances in thermoelectric Bi2Te3 and CoSb3 based nanomaterials are summarized. Advanced synthesis and characterization methods and theoreticalmodelingwere combined to assess and reduce ZT-limiting mechanisms in these materials.« less

  2. News-PHaSe-EFRC

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

    News and Highlights Saxony This page shows highlights and news items about PHaSE activities, research achievements, and people; archived items can be accessed by year at the menu to the left. If you have questions about any items, or want to know more, please contact either Tom Russell or D. Venkataraman. Final archive date: 26 April

  3. Method of producing superconducting fibers of bismuth strontium calcium copper oxide (Bi(2212) and Bi(2223))

    DOE Patents [OSTI]

    Schwartzkopf, Louis A.

    1991-10-01

    Fibers of Bi(2212) have been produce by pendant drop melt extraction. This technique involves the end of a rod of Bi(2212) melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 15 cm in length with the usual lateral dimensions, ranging from 20 um to 30 um. The fibers require a heat treatment to make them superconducting.

  4. Growth of Sb-Bi gradient single crystals

    SciTech Connect (OSTI)

    Kozhemyakin, G. N. Lutskiy, D. V.; Rom, M. A.; Mateychenko, P. V.

    2008-12-15

    The growth conditions and structural quality of Sb-Bi gradient single crystals with Bi content from 2 to 18 at %, grown by the Czochralski method with solid phase feed, are investigated. Bi distribution in the crystals along their pulling direction are studied by electron probe microanalysis and the change in the interplanar spacing is analyzed by double-crystal X-ray diffraction. It is established that the pulling rate and feed mass affect the Bi distribution in Sb-Bi single crystals.

  5. Green route synthesis of high quality CdSe quantum dots for applications in light emitting devices

    SciTech Connect (OSTI)

    Bera, Susnata, E-mail: susnata.bera@gmail.com [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Singh, Shashi B. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Ray, S.K., E-mail: physkr@phy.iitkgp.ernet.in [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2012-05-15

    Investigation was made on light emitting diodes fabricated using CdSe quantum dots. CdSe quantum dots were synthesized chemically using olive oil as the capping agent, instead of toxic phosphine. Room temperature photoluminescence investigation showed sharp 1st excitonic emission peak at 568 nm. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting devices were fabricated by solution process. The electroluminescence study showed low turn on voltage ({approx}2.2 V) .The EL peak intensity was found to increase by increasing the operating current. - Graphical abstract: Light emitting diode was fabricated using CdSe quantum dots using olive oil as the capping agent, instead of toxic phosphine. Bi-layer organic/inorganic (P3HT/CdSe) hybrid light emitting device shows strong electroluminescence in the range 630-661 nm. Highlights: Black-Right-Pointing-Pointer CdSe Quantum dots were synthesized using olive oil as the capping agent. Black-Right-Pointing-Pointer Light emitting device was fabricated using CdSe QDs/P3HT polymer heterojunction. Black-Right-Pointing-Pointer The I-V characteristics study showed low turn on voltage at {approx}2.2 V. Black-Right-Pointing-Pointer The EL peak intensity increases with increasing the operating current.

  6. Barron: Noncompliance Determination (2013-SE-5402) | Department...

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

    Noncompliance Determination (2013-SE-5402) Barron: Noncompliance Determination (2013-SE-5402) December 17, 2015 DOE issued a Notice of Noncompliance Determination to Barron ...

  7. Shandong Hongtai: Noncompliance Determination (2016-SE-42010...

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

    Noncompliance Determination (2016-SE-42010) Shandong Hongtai: Noncompliance Determination (2016-SE-42010) January 6, 2016 DOE issued a Notice of Noncompliance Determination to ...

  8. I2SE | Open Energy Information

    Open Energy Info (EERE)

    I2SE Jump to: navigation, search Name: I2SE Place: Leipzig, Germany Zip: 4103 Sector: Efficiency Product: IT company providing solutions for energy efficiency and data...

  9. SE Project Srl | Open Energy Information

    Open Energy Info (EERE)

    search Name: SE Project Srl Place: San Pietro, Italy Zip: 35010 Sector: Solar Product: Italian manufacturer and supplier of solar modules and solar technology. References: SE...

  10. Systems and methods for bi-directional energy delivery with galvanic isolation

    DOE Patents [OSTI]

    Kajouke, Lateef A.

    2013-06-18

    Systems and methods are provided for bi-directional energy delivery. A charging system comprises a first bi-directional conversion module, a second bi-directional conversion module, and an isolation module coupled between the first bi-directional conversion module and the second bi-directional conversion module. The isolation module provides galvanic isolation between the first bi-directional conversion module and the second bi-directional conversion module.

  11. Superconductivity in semimetallic Bi3O2S3

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

    Li, L.; Parker, D.; Babkevich, P.; Yang, L.; Ronnow, H. M.; Sefat, A. S.

    2015-03-12

    We report in this paper a further investigation on the thermodynamic and transport properties, and an assessment of theoretical calculations, for the BiS2-layered Bi3O2S3 superconductor. The polycrystalline sample is synthesized with a superconducting transition temperature of Tconset=5.75K and Tczero=4.03K (≈Tcmag) that drops to 3.3 K by applying a hydrostatic pressure of 6 kbar. Density-of-states (DOS) calculations give substantial hybridization between Bi, O, and S, with Bi the largest component of DOS, which supports the idea that the BiS2 layer is relevant for producing electron-phonon coupling. An analysis of previously published specific heat data for Bi3O2S3 is additionally suggestive of amore » strong electron-phonon interaction in the Bi-O-S system. The analysis of the Seebeck coefficient results strongly suggests that Bi3O2S3 is a semimetal. In fact, we found the semimetallic or narrow band gap behavior may occur in certain other materials in the BiS2-layered class of materials, such as Bi4O4S3.« less

  12. Midea: Noncompliance Determination (2013-SE-1505)

    Broader source: Energy.gov [DOE]

    DOE issued a Notice of Noncompliance Determination to GD Midea Air-Conditioning Equipment Co. Ltd. finding that Arctic King brand room air conditioner basic model MWJ1-08ERN1-BI8, manufactured by Midea, does not comport with the energy conservation standards.

  13. Process and apparatus for the production of BI-213 cations

    DOE Patents [OSTI]

    Horwitz, E. Philip; Hines, John J.; Chiarizia, Renato; Dietz, Mark

    1998-01-01

    A process for producing substantially impurity-free Bi-213 cations is disclosed. An aqueous acid feed solution containing Ac-225 cations is contacted with an ion exchange medium to bind the Ac-225 cations and form an Ac-225-laden ion exchange medium. The bound Ac-225 incubates on the ion exchange medium to form Bi-213 cations by radioactive decay. The Bi-213 cations are then recovered from the Ac-225-laden ion exchange medium to form a substantially impurity-free aqueous Bi-213 cation acid solution. An apparatus for carrying out this process is also disclosed.

  14. Process and apparatus for the production of Bi-213 cations

    DOE Patents [OSTI]

    Horwitz, E.P.; Hines, J.J.; Chiarizia, R.; Dietz, M.

    1998-12-29

    A process for producing substantially impurity-free Bi-213 cations is disclosed. An aqueous acid feed solution containing Ac-225 cations is contacted with an ion exchange medium to bind the Ac-225 cations and form an Ac-225-laden ion exchange medium. The bound Ac-225 incubates on the ion exchange medium to form Bi-213 cations by radioactive decay. The Bi-213 cations are then recovered from the Ac-225-laden ion exchange medium to form a substantially impurity-free aqueous Bi-213 cation acid solution. An apparatus for carrying out this process is also disclosed. 7 figs.

  15. Itinerant effects and enhanced magnetic interactions in Bi-based...

    Office of Scientific and Technical Information (OSTI)

    and enhanced magnetic interactions in Bi-based multilayer cuprates Dean, M. P. M. Brookhaven National Lab. (BNL), Upton, NY (United States). Department of Condensed Matter...

  16. Application Assessment of Bi-Level LED Parking Lot Lighting

    SciTech Connect (OSTI)

    Johnson, Megan; Cook, Tyson; Shackelford, Jordan; Pang, Terrance

    2009-02-01

    This report summarizes an assessment project conducted to evaluate light-emitting diode (LED) luminaires with bi-level operation in an outdoor parking lot application.

  17. Bi-Con Services Inc | Open Energy Information

    Open Energy Info (EERE)

    Services Inc Jump to: navigation, search Name: Bi-Con Services Inc Address: 10901 Clay Pike Road Place: Derwent, Ohio Zip: 43733 Sector: Buildings, Efficiency, Services Product:...

  18. Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells

    SciTech Connect (OSTI)

    Shafarman, William N.

    2015-10-12

    This project “Advanced Precursor Reaction Processing for Cu(InGa)(SeS)2 Solar Cells”, completed by the Institute of Energy Conversion (IEC) at the University of Delaware in collaboration with the Department of Chemical Engineering at the University of Florida, developed the fundamental understanding and technology to increase module efficiency and improve the manufacturability of Cu(InGa)(SeS)2 films using the precursor reaction approach currently being developed by a number of companies. Key results included: (1) development of a three-step H2Se/Ar/H2S reaction process to control Ga distribution through the film and minimizes back contact MoSe2 formation; (2) Ag-alloying to improve precursor homogeneity by avoiding In phase agglomeration, faster reaction and improved adhesion to allow wider reaction process window; (3) addition of Sb, Bi, and Te interlayers at the Mo/precursor junction to produce more uniform precursor morphology and improve adhesion with reduced void formation in reacted films; (4) a precursor structure containing Se and a reaction process to reduce processing time to 5 minutes and eliminate H2Se usage, thereby increasing throughput and reducing costs. All these results were supported by detailed characterization of the film growth, reaction pathways, thermodynamic assessment and device behavior.

  19. Bi-Directional Fast Charging Study Report

    SciTech Connect (OSTI)

    Tyler Gray

    2012-02-01

    This report details the hardware and software infrastructure needed to demonstrate the possibility of utilizing battery power in plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) with a bi directional fast charger to support/offset peak building loads. This document fulfills deliverable requirements for Tasks 1.2.1.2, 1.2.1.3, and 1.2.1.4 of Statement of Work (SOW) No.5799 for Electric Transportation Engineering Corporation, now ECOtality North America (NA) support for the Idaho National Laboratory (INL).

  20. Bi-directional planar slide mechanism

    DOE Patents [OSTI]

    Bieg, Lothar F.

    2003-11-04

    A bi-directional slide mechanism. A pair of master and slave disks engages opposite sides of the platform. Rotational drivers are connected to master disks so the disks rotate eccentrically about their respective axes of rotation. Opposing slave disks are connected to master disks on opposite sides of the platform by a circuitous mechanical linkage, or are electronically synchronized together using stepper motors, to effect coordinated motion. The synchronized eccentric motion of the pairs of master/slave disks compels smooth linear motion of the platform forwards and backwards without backlash. The apparatus can be incorporated in a MEMS device.

  1. One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres with enhanced photocatalytic performance

    SciTech Connect (OSTI)

    Qu, Lingling; Luo, Zhijun; Tang, Chao

    2013-11-15

    Graphical abstract: Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon coreshell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs). Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation. - Highlights: One step synthesis of Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon spheres. Functional groups of sodium gluconate play synergetic roles in the formation of Bi@Bi{sub 2}O{sub 3}@CRCSs. Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits enhanced photocatalytic activity under visible light irradiation. - Abstract: Bi@Bi{sub 2}O{sub 3}@carboxylate-rich carbon core-shell nanosturctures (Bi@Bi{sub 2}O{sub 3}@CRCSs) have been synthesized via a one-step method. The coreshell nanosturctures of the as-prepared samples were confirmed by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and Raman spectroscopy. The formation of Bi@Bi{sub 2}O{sub 3}@CRCSs coreshell nanosturctures should attribute to the synergetic roles of different functional groups of sodium gluconate. Bi@Bi{sub 2}O{sub 3}@CRCSs exhibits significant enhanced photocatalytic activity under visible light irradiation (? > 420 nm) and shows an O{sub 2}-dependent feature. According to trapping experiments of radicals and holes, hydroxyl radicals were not the main active oxidative species in the photocatalytic degradation of MB, but O{sub 2}{sup ?} are the main active oxidative species.

  2. Superconductivity in strong spin orbital coupling compound Sb2Se3

    SciTech Connect (OSTI)

    Kong, P. P.; Sun, F.; Xing, L. Y.; Zhu, J.; Zhang, S. J.; Li, W. M.; Liu, Q. Q.; Wang, X. C.; Feng, S. M.; Yu, X. H.; Zhu, J. L.; Yu, R. C.; Yang, W. G.; Shen, G. Y.; Zhao, Y. S.; Ahuja, R.; Mao, H. K.; Jin, C. Q.

    2014-10-20

    Recently, A2B3 type strong spin orbital coupling compounds such as Bi2Te3, Bi2Se3 and Sb2Te3 were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb2Se3 on the other hand was found to be topological trivial, but theoretical studies indicated that the pressure might induce Sb2Se3 into a topological nontrivial state. We report on the discovery of superconductivity in Sb2Se3 single crystal induced via pressure. Our experiments indicated that Sb2Se3 became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at ~3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (TC) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. As a result, high pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of TC slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.

  3. The 209Bi(nth,{gamma})210Bi and 209Bi(nth,{gamma})210m,gBi Cross Sections Determined at the Budapest Neutron Centre

    SciTech Connect (OSTI)

    Borella, A.; Schillebeeckx, P.; Molnar, G.; Belgya, T.; Revay, Zs.; Szentmiklosi, L.; Berthoumieux, E.; Gunsing, F.; Letourneau, A.; Marie, F.

    2005-05-24

    The neutron total capture cross section of 209Bi together with the cross sections to the ground state and the isomeric state were determined at the cold neutron beam PGAA-NIPS facilities at the Budapest Neutron Centre. For the measurements we used a coaxial HPGe detector with Compton suppression. The partial {gamma}-ray production cross sections were deduced relative to the partial capture cross section for the 4055 keV transition following 209Bi(n,{gamma}). This partial cross section was measured with a bismuth nitrate sample with respect to nitrogen as a comparator. The total capture cross section resulting from the primary transitions is lower than the one deduced from the transitions feeding the isomeric and the ground state. Since the multipolarity of the main transition feeding the ground state is not known, the uncertainty on the capture cross section to the ground state is rather large. We also compare the total capture thermal cross section with the value deduced from resonance parameters and discuss the impact of the branching ratio on the analysis of prompt capture cross section measurements using the total energy detection principle.

  4. Extreme solid state refrigeration using nanostructured Bi-Te alloys.

    SciTech Connect (OSTI)

    Lima Sharma, Ana L.; Spataru, Dan Catalin; Medlin, Douglas L.; Sharma, Peter Anand; Morales, Alfredo Martin

    2009-09-01

    Materials are desperately needed for cryogenic solid state refrigeration. We have investigated nanostructured Bi-Te alloys for their potential use in Ettingshausen refrigeration to liquid nitrogen temperatures. These alloys form alternating layers of Bi{sub 2} and Bi{sub 2}Te{sub 3} blocks in equilibrium. The composition Bi{sub 4}Te{sub 3} was identified as having the greatest potential for having a high Ettingshausen figure of merit. Both single crystal and polycrystalline forms of this material were synthesized. After evaluating the Ettingshausen figure of merit for a large, high quality polycrystal, we simulated the limits of practical refrigeration in this material from 200 to 77 K using a simple device model. The band structure was also computed and compared to experiments. We discuss the crystal growth, transport physics, and practical refrigeration potential of Bi-Te alloys.

  5. Li2Se as a Neutron Scintillator

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

    Du, Mao-Hua; Shi, Hongliang; Singh, David J.

    2015-06-23

    We show that Li2Se:Te is a potential neutron scintillator material based on density functional calculations. Li2Se exhibits a number of properties favorable for efficient neutron detection, such as a high Li concentration for neutron absorption, a small effective atomic mass and a low density for reduced sensitivity to background gamma rays, and a small band gap for a high light yield. Our calculations show that Te doping should lead to the formation of deep acceptor complex VLi-TeSe, which can facilitate efficient light emission, similar to the emission activation in Te doped ZnSe.

  6. Oxidation of ultrathin GaSe

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

    Thomas Edwin Beechem; McDonald, Anthony E.; Ohta, Taisuke; Howell, Stephen W.; Kalugin, Nikolai G.; Kowalski, Brian M.; Brumbach, Michael T.; Spataru, Catalin D.; Pask, Jesse A.

    2015-10-26

    Oxidation of exfoliated gallium selenide (GaSe) is investigated through Raman, photoluminescence, Auger, and X-ray photoelectron spectroscopies. Photoluminescence and Raman intensity reductions associated with spectral features of GaSe are shown to coincide with the emergence of signatures emanating from the by-products of the oxidation reaction, namely, Ga2Se3 and amorphous Se. Furthermore, photoinduced oxidation is initiated over a portion of a flake highlighting the potential for laser based patterning of two-dimensional heterostructures via selective oxidation.

  7. Oxidation of ultrathin GaSe

    SciTech Connect (OSTI)

    Thomas Edwin Beechem; McDonald, Anthony E.; Ohta, Taisuke; Howell, Stephen W.; Kalugin, Nikolai G.; Kowalski, Brian M.; Brumbach, Michael T.; Spataru, Catalin D.; Pask, Jesse A.

    2015-10-26

    Oxidation of exfoliated gallium selenide (GaSe) is investigated through Raman, photoluminescence, Auger, and X-ray photoelectron spectroscopies. Photoluminescence and Raman intensity reductions associated with spectral features of GaSe are shown to coincide with the emergence of signatures emanating from the by-products of the oxidation reaction, namely, Ga2Se3 and amorphous Se. Furthermore, photoinduced oxidation is initiated over a portion of a flake highlighting the potential for laser based patterning of two-dimensional heterostructures via selective oxidation.

  8. Q Cells SE | Open Energy Information

    Open Energy Info (EERE)

    Name: Q-Cells SE Place: Thalheim, Brandenburg, Germany Zip: 6766 Product: German PV cell manufacturer; also makes strategic venture capital and corporate investments....

  9. Templates-Resources-PHaSe-EFRC

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

    templates 36 inch high by 48 inch wide, landscape poster template with PHaSE acknowledgements (PPT file download) 36 inch high by 48 inch wide, landscape poster template with PHaSE acknowledgements, 12-panel layout (typical pattern used by UMass PSE) (PPT file download) 42 inch high by 48 inch wide, landscape poster template with PHaSE acknowledgements (PPT file download) 36 inch high by 48 inch wide, portrait poster template with PHaSE acknowledgements (PPT file download) 16:9 Slide Templates

  10. Crystal Splitting in the Growth of Bi2S3

    SciTech Connect (OSTI)

    Tang, Jing; Alivisatos, A. Paul

    2006-06-15

    Novel Bi{sub 2}S{sub 3} nanostructures with a sheaf-like morphology are obtained via reaction of bismuth acetate-oleic acid complex with elemental sulfur in 1-octadecence. We propose these structures form by the splitting crystal growth mechanism, which is known to account for the morphology some mineral crystals assume in nature. By controlling the synthetic parameters, different forms of splitting, analogous to observed in minerals, are obtained in our case of Bi{sub 2}S{sub 3}. These new and complex Bi{sub 2}S{sub 3} nanostructures are characterized by TEM, SEM, XRD and ED.

  11. Improving combustion stability in a bi-fuel engine

    SciTech Connect (OSTI)

    1995-06-01

    This article describes how a new strategy for ignition timing control can reduce NOx emissions from engines using CNG and gasoline. Until a proper fueling infrastructure is established, a certain fraction of vehicles powered by compressed natural gas (CNG) must have bi-fuel capability. A bi-fuel engine, enjoying the longer range of gasoline and the cleaner emissions of CNG, can overcome the problem of having few CNG fueling stations. However, bi-fuel engines must be optimized to run on both fuels since low CNG volumetric efficiency causes power losses compared to gasoline.

  12. Behavior of intruder based states in light Bi and Tl isotopes: the study of {sup 187 Bi} {alpha} decay

    SciTech Connect (OSTI)

    Batchelder, J.C.; Zganjar, E.F.

    1997-01-01

    Intruder state excitation energies in odd-mass nuclei just outside a closed proton shell plotted versus neutron number generally exhibit parabola-shaped curves with minima near neutron mid-shells. The Bi isotopes, however, do not seem to follow this trend. Recent experiments performed at Argonne National Laboratory have identified the previously unobserved {sup 187}Bi ground state (h{sub 9/2}) to {sup 183}TI ground state s{sub 1/2} {alpha} transition. Its energy when combined with those of two earlier known transitions, namely {sup 187}Bi (h{sub 9/2}) {yields} {sup 183m}Tl (h{sub 9/2}) and {sup 187m}Bi (s{sub 1/2}) {yields} {sup 183}Tl(s{sub 1/2}), establishes the excitation energies of the {sup 183m}Tl and {sup 187m}Bi to be 620(20) keV and 110(20) keV, respectively. This value for {sup 187m}Bi is 80 keV lower than the excitation energy of the same intruder level in {sup 189}Bi. Implications of this result with respect to intruder-state systematics are discussed.

  13. From thermoelectric bulk to nanomaterials: Current progress for Bi 2 Te 3 and CoSb 3: From thermoelectric bulk to nanomaterials

    SciTech Connect (OSTI)

    Peranio, N.; Eibl, O.; Bäßler, S.; Nielsch, K.; Klobes, B.; Hermann, R. P.; Daniel, M.; Albrecht, M.; Görlitz, H.; Pacheco, V.; Bedoya-Martínez, N.; Hashibon, A.; Elsässer, C.

    2015-10-29

    We synthesized Bi2Te3 and CoSb3 based nanomaterials and their thermoelectric, structural, and vibrational properties analyzed to assess and reduce ZT-limiting mechanisms. The same preparation and/or characterization methods were applied in the different materials systems. Single-crystalline, ternary p-type Bi15Sb29Te56, and n-type Bi38Te55Se7 nanowires with power factors comparable to nanostructured bulkmaterialswere prepared by potential-pulsed electrochemical deposition in a nanostructured Al2O3 matrix. p-type Sb2Te3, n-type Bi2Te3, and n-type CoSb3 thin films were grown at room temperature using molecular beam epitaxy and were subsequently annealed at elevated temperatures. It yielded polycrystalline, single phase thin films with optimized charge carrier densities. In CoSb3 thin films the speed of sound could be reduced by filling the cage structure with Yb and alloying with Fe yielded p-type material. Bi2(Te0.91Se0.09)3/SiC and (Bi0.26Sb0.74)2Te3/SiC nanocomposites with low thermal conductivities and ZT values larger than 1 were prepared by spark plasma sintering. Nanostructure, texture, chemical composition, as well as electronic and phononic excitations were investigated by X-ray diffraction, nuclear resonance scattering, inelastic neutron scattering, M ossbauer spectroscopy, and transmission electron microscopy. Furthermore, for Bi2Te3 materials, ab-initio calculations together with equilibrium and non-equilibrium molecular dynamics simulations for point defects yielded their formation energies and their effect on lattice thermal conductivity, respectively. Current advances in thermoelectric Bi2Te3 and CoSb3 based nanomaterials are

  14. Enhanced Superconducting Gaps in Trilayer High-Temperature Bi...

    Office of Scientific and Technical Information (OSTI)

    ...-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor Citation Details In-Document Search Title: Enhanced Superconducting Gaps in Trilayer High-Temperature ...

  15. Melt processing of Bi--2212 superconductors using alumina

    DOE Patents [OSTI]

    Holesinger, Terry G.

    1999-01-01

    Superconducting articles and a method of forming them, where the superconducting phase of an article is Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.y (Bi-2212). Alumina is combined with Bi-2212 powder or Bi-2212 precursor powder and, in order to form an intimate mixture, the mixture is melted and rapidly cooled to form a glassy solid. The glassy solid is comminuted and the resulting powder is combined with a carrier. An alternative to melting is to form the mixture of nanophase alumina and material having a particle size of less than about 10 microns. The powder, with the carrier, is melt processed to form a superconducting article.

  16. Electrochemically deposited BiTe-based nanowires for thermoelectric applications

    SciTech Connect (OSTI)

    Ng, Inn-Khuan; Kok, Kuan-Ying; Rahman, Che Zuraini Che Ab; Saidin, Nur Ubaidah; Ilias, Suhaila Hani; Choo, Thye-Foo

    2014-02-12

    Nanostructured materials systems such as thin-films and nanowires (NWs) are promising for thermoelectric power generation and refrigeration compared to traditional counterparts in bulk, due to their enhanced thermoelectric figures-of-merit. BiTe and its derivative compounds, in particular, are well-known for their near-room temperature thermoelectric performance. In this work, both the binary and ternary BiTe-based nanowires namely, BiTe and BiSbTe, were synthesized using template-assisted electrodeposition. Diameters of the nanowires were controlled by the pore sizes of the anodised alumina (AAO) templates used. Systematic study on the compositional change as a function of applied potential was carried out via Linear Sweep Voltanmetry (LSV). Chemical compositions of the nanowires were studied using Energy Dispersive X-ray Spectrometry (EDXS) and their microstructures evaluated using diffraction and imaging techniques. Results from chemical analysis on the nanowires indicated that while the Sb content in BiSbTe nanowires increased with more negative deposition potentials, the formation of Te{sup 0} and Bi{sub 2}Te{sub 3} were favorable at more positive potentials.

  17. SE Drive Technik | Open Energy Information

    Open Energy Info (EERE)

    Drive Technik Jump to: navigation, search Name: SE Drive Technik Place: Bochum, Germany Zip: 44791 Product: Germany-based R&D subsidiary of Indian turbine maker Suzlon. References:...

  18. Facilities-Resources-PHaSe-EFRC

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

    Various PHaSE EFRC equipment may be accessed by making arrangments for training and acceptance to the list of registered users. Access to the facility rooms requires a password ...

  19. 2013 Archives-News-PHaSe-EFRC

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

    3 Archives Volodimyr Duzhko photo Volodimyr Duzhko promoted to (extension) Assistant Professor of Polymer Science & Engineering. PHaSE is pleased to announce that Facility Director Dr. Volodimyr Duzhko has been promoted to extension Assistant Professor of Polymer Science & Engineering. Volodimyr is a semiconductor physicist with considerable experience in polymer materials. Since joining PHaSE, he has trained over 70 people to use 10 instruments in the Photovoltaic & Optical

  20. A transferable force field for CdS-CdSe-PbS-PbSe solid systems

    SciTech Connect (OSTI)

    Fan, Zhaochuan; Vlugt, Thijs J. H.; Koster, Rik S.; Fang, Changming; Huis, Marijn A. van; Wang, Shuaiwei; Yalcin, Anil O.; Tichelaar, Frans D.; Zandbergen, Henny W.

    2014-12-28

    A transferable force field for the PbSe-CdSe solid system using the partially charged rigid ion model has been successfully developed and was used to study the cation exchange in PbSe-CdSe heteronanocrystals [A. O. Yalcin et al., “Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth,” Nano Lett. 14, 3661–3667 (2014)]. In this work, we extend this force field by including another two important binary semiconductors, PbS and CdS, and provide detailed information on the validation of this force field. The parameterization combines Bader charge analysis, empirical fitting, and ab initio energy surface fitting. When compared with experimental data and density functional theory calculations, it is shown that a wide range of physical properties of bulk PbS, PbSe, CdS, CdSe, and their mixed phases can be accurately reproduced using this force field. The choice of functional forms and parameterization strategy is demonstrated to be rational and effective. This transferable force field can be used in various studies on II-VI and IV-VI semiconductor materials consisting of CdS, CdSe, PbS, and PbSe. Here, we demonstrate the applicability of the force field model by molecular dynamics simulations whereby transformations are initiated by cation exchange.

  1. 2011 Archives-News-PHaSe-EFRC

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

    1 Archives solar cells video clip Solar Cells from Plastics? Mission Possible at the PHaSE energy research center, UMass Amherst!, a YouTube video about work at PHaSE, debuted on 24 March 2011. This video is part of our center's contributions to the Energy Frontier Research Centers Summit & Forum on 25-27 May 2011, which is further described below. Many thanks to Harihara Venkatraman (DV group, ERG 1) and Dr. Emily Pentzer (Emrick group, ERG 1) for starring in the video clip, along with

  2. Pressure-enhanced superconductivity in Eu 3 Bi 2 S 4 F 4 (Journal...

    Office of Scientific and Technical Information (OSTI)

    The pressure effect on the newly discovered charge-transferred BiS2-based superconductor, Eu3Bi2S4F4, with a Tc of 1.5 K at ambient pressure, is investigated by transport and ...

  3. Design and optimization of a bi-axial vibration-driven electromagnetic...

    Office of Scientific and Technical Information (OSTI)

    Design and optimization of a bi-axial vibration-driven electromagnetic generator Citation Details In-Document Search Title: Design and optimization of a bi-axial vibration-driven ...

  4. Resonant Level Enhancement of the Thermoelectric Power of Bi2Te3...

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

    Resonant Level Enhancement of the Thermoelectric Power of Bi2Te3 with Tin Resonant Level Enhancement of the Thermoelectric Power of Bi2Te3 with Tin Application to practical p-type...

  5. New York Event to Show Bi-Partisan, International Support for...

    Office of Environmental Management (EM)

    New York Event to Show Bi-Partisan, International Support for Geothermal Energy in America New York Event to Show Bi-Partisan, International Support for Geothermal Energy in ...

  6. Pressure-enhanced superconductivity in Eu 3 Bi 2 S 4 F 4 (Journal...

    Office of Scientific and Technical Information (OSTI)

    Title: Pressure-enhanced superconductivity in Eu 3 Bi 2 S 4 F 4 The pressure effect on the newly discovered charge-transferred BiS2-based superconductor, Eu3Bi2S4F4, with a Tc of ...

  7. Variation of lattice constant and cluster formation in GaAsBi

    SciTech Connect (OSTI)

    Puustinen, J.; Schramm, A.; Guina, M.; Wu, M.; Luna, E.; Laukkanen, P.; Laitinen, M.; Sajavaara, T.

    2013-12-28

    We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220315 C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out of the layer during annealing. However, dark-field and Z-contrast transmission electron microscopy analyses revealed the formation of GaAsBi clusters with a Bi content higher than in the surrounding matrix, as well as the presence of metallic As clusters. The apparent reduction of the lattice constant can be explained by a two-fold process: the diffusion of the excess As incorporated within As{sub Ga} antisites to As clusters, and the reduction of the Bi content in the GaAs matrix due to diffusion of Bi to GaAsBi clusters. Diffusion of both As and Bi are believed to be assisted by the native point defects, which are present in the low-temperature as-grown material.

  8. Anisotropy in CdSe quantum rods

    SciTech Connect (OSTI)

    Li, Liang-shi

    2003-09-01

    The size-dependent optical and electronic properties of semiconductor nanocrystals have drawn much attention in the past decade, and have been very well understood for spherical ones. The advent of the synthetic methods to make rod-like CdSe nanocrystals with wurtzite structure has offered us a new opportunity to study their properties as functions of their shape. This dissertation includes three main parts: synthesis of CdSe nanorods with tightly controlled widths and lengths, their optical and dielectric properties, and their large-scale assembly, all of which are either directly or indirectly caused by the uniaxial crystallographic structure of wurtzite CdSe. The hexagonal wurtzite structure is believed to be the primary reason for the growth of CdSe nanorods. It represents itself in the kinetic stabilization of the rod-like particles over the spherical ones in the presence of phosphonic acids. By varying the composition of the surfactant mixture used for synthesis we have achieved tight control of the widths and lengths of the nanorods. The synthesis of monodisperse CdSe nanorods enables us to systematically study their size-dependent properties. For example, room temperature single particle fluorescence spectroscopy has shown that nanorods emit linearly polarized photoluminescence. Theoretical calculations have shown that it is due to the crossing between the two highest occupied electronic levels with increasing aspect ratio. We also measured the permanent electric dipole moment of the nanorods with transient electric birefringence technique. Experimental results on nanorods with different sizes show that the dipole moment is linear to the particle volume, indicating that it originates from the non-centrosymmetric hexagonal lattice. The elongation of the nanocrystals also results in the anisotropic inter-particle interaction. One of the consequences is the formation of liquid crystalline phases when the nanorods are dispersed in solvent to a high enough

  9. Selective hydrothermal synthesis of BiOBr microflowers and Bi{sub 2}O{sub 3} shuttles with concave surfaces

    SciTech Connect (OSTI)

    Xiao Peipei; Zhu Lingling; Zhu Yongchun; Qian Yitai

    2011-06-15

    Through controlling the amount of NaOH added, BiOBr and Bi{sub 2}O{sub 3} with different shapes were hydrothermally synthesized in the reaction system of Bi(NO{sub 3}){sub 3}-hexadecyl trimethyl ammonium bromide (CTAB)-NaOH. As 8 mmol of NaOH was added, BiOBr microflowers constructed of nanoflakes were synthesized. The thickness of these single-crystal nanoflakes was about 20 nm. In the similar condition, when the amount of NaOH added was 28 mmol, Bi{sub 2}O{sub 3} shuttles with concave surfaces were obtained. The length of these shuttles was 100 {mu}m and the diameter at the middle of these shuttles was 50 {mu}m. The photocatalytic activity of as-prepared BiOBr microflowers was evaluated by the degradation of methyl orange (MO) under visible-light irradiation ({lambda}>420 nm), which was up to 96% within 90 min. - Graphical abstract: Through controlling the amount of NaOH added, BiOBr microflowers and Bi{sub 2}O{sub 3} shuttles with concave surfaces were hydrothermally synthesized in the reaction system of Bi(NO{sub 3}){sub 3}-hexadecyl trimethyl ammonium bromide (CTAB)-NaOH. Highlights: > BiOBr microflowers constructed of nanoflakes were synthesized hydrothermally. > Bi{sub 2}O{sub 3} shuttles with concave surfaces were also synthesized. > Their formation mechanisms were studied based on the experimental results. > The photocatalytic activity of BiOBr microflowers was evaluated under visible-light irradiation.

  10. Highly efficient visible-light-induced photocatalytic activity of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts

    SciTech Connect (OSTI)

    Chaiwichian, Saranyoo; Inceesungvorn, Burapat; Wetchakun, Khatcharin; Phanichphant, Sukon; Kangwansupamonkon, Wiyong; Wetchakun, Natda

    2014-06-01

    Highlights: Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were obtained using hydrothermal method. Physicochemical properties played a significant role on photocatalytic efficiency. Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterogeneous structures were greatly enhanced for degradation of MB. A tentative mechanism of charge transfer process in MB degradation was proposed. - Abstract: The Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were synthesized by hydrothermal method. Physical properties of the heterojunction photocatalyst samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The XRD results indicated that BiVO{sub 4} retain monoclinic and tetragonal structures, while Bi{sub 2}WO{sub 6} presented as orthorhombic structure. The Brunauer, Emmett and Teller (BET) adsorptiondesorption of nitrogen gas for specific surface area determination at the temperature of liquid nitrogen was performed on all samples. UVvis diffuse reflectance spectra (UVvis DRS) were used to identify the absorption range and band gap energy of the heterojunction photocatalysts. The photocatalytic performance of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts was studied via the photodegradation of methylene blue (MB) under visible light irradiation. The results indicated that the heterojunction photocatalyst at 0.5:0.5 mole ratio of Bi{sub 2}WO{sub 6}:BiVO{sub 4} shows the highest photocatalytic activity.

  11. UMass-Resources-PHaSe-EFRC

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

    UMass Resources UMass logo The following links provide information about important local (UMass Amherst) campus and departmental offices and resources, including major interdepartmental research centers that pursue work closely akin to research that was initiated or expanded under PHaSE. The last four links go to sites with energy or research news of potential interest to scientists interested in organic electronic materails. Major UMass User Facilities Vice-Chancellor for Research UMass

  12. Organization-About-PHaSe-EFRC

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

    About Mission Statement (PDF) Organization Contact Us organization This webpage is provided for legacy archive purposes only, as of 30 April 2015. The day to day operations of the University of Massachusetts Amherst PHaSE EFRC are administered by co-directors. Russell is the Samuel Conte Distingushed Professor of Polymer Science and Engineering, with years of previous experience at IBM Research, over 620 publications and 21 patents for polymer chemistry and physics. Lahti has over 29 years at

  13. SE Great Basin Play Fairway Analysis

    SciTech Connect (OSTI)

    Adam Brandt

    2015-11-15

    This submission includes a Na/K geothermometer probability greater than 200 deg C map, as well as two play fairway analysis (PFA) models. The probability map acts as a composite risk segment for the PFA models. The PFA models differ in their application of magnetotelluric conductors as composite risk segments. These PFA models map out the geothermal potential in the region of SE Great Basin, Utah.

  14. 2010 Archives-News-PHaSe-EFRC

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

    0 Archives PHaSE welcomes Dr. Lawrence Friedman as our new Managing Director. Larry comes to us with strong backgrounds in both academic and industrial experience. He is well acquainted with UMass Amherst from his time at Bayer Materials Science, where he was much involved in doctoral level recruiting and in academic/industrial liaison work as Head of University Relations. Before this, he was at Polaroid doing work in flims research as a manager and senior scientist. His academic credentials

  15. 2013 Archives-News-PHaSe-EFRC

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

    4 Archives PHaSE EFRC work was featured in an MRS-TV video production, UMASS Amherst -- Optimal Design: Interdisciplinary Teamwork from Synthesis to Production, that was highlighted on electronic signage throughout the Fall 2014 Boston Materials Research Society meeting. Major vignettes were shown from Maroudas group, DV group, Emrick group. Both faculty and undergraduates/graduates/postdocs described EFRC work and work being carried out by closely allied groups interested in energy-related

  16. Superconductivity versus structural phase transition in the closely related Bi2Rh3.5S2 and Bi2Rh3S2

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

    Kaluarachchi, Udhara S.; Xie, Weiwei; Lin, Qisheng; Taufour, Valentin; Bud'ko, Sergey L.; Miller, Gordon J.; Canfield, Paul C.

    2015-05-19

    Single crystals of Bi2Rh3S2 and Bi2Rh3.5S2 were synthesized by solution growth, and the crystal structures and thermodynamic and transport properties of both compounds were studied. In the case of Bi2Rh3S2, a structural first-order transition at around 165 K is identified by single-crystal diffraction experiments, with clear signatures visible in resistivity, magnetization, and specific heat data. No superconducting transition for Bi2Rh3S2 was observed down to 0.5 K. In contrast, no structural phase transition at high temperature was observed for Bi2Rh3.5S2; however, bulk superconductivity with a critical temperature, Tc ≈ 1.7 K, was observed. The Sommerfeld coefficient γ and the Debye temperaturemore » (ΘD) were found to be 9.41 mJ mol–1K–2 and 209 K, respectively, for Bi2Rh3S2, and 22 mJ mol–1K–2 and 196 K, respectively, for Bi2Rh3.5S2. As a result, the study of the specific heat in the superconducting state of Bi2Rh3.5S2 suggests that Bi2Rh3.5S2 is a weakly coupled, BCS superconductor.« less

  17. Comparison of growth texture in round Bi2212 and flat Bi2223 wires and its relation to high critical current density development

    SciTech Connect (OSTI)

    Kametani, F.; Jiang, J.; Matras, M.; Abraimov, D.; Hellstrom, E. E.; Larbalestier, D. C.

    2015-02-10

    Why Bi₂Sr₂CaCu₂Ox (Bi2212) allows high critical current density Jc in round wires rather than only in the anisotropic tape form demanded by all other high temperature superconductors is important for future magnet applications. Here we compare the local texture of state-of-the-art Bi2212 and Bi2223 ((Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀), finding that round wire Bi2212 generates a dominant a-axis growth texture that also enforces a local biaxial texture (FWHM <15°) while simultaneously allowing the c-axes of its polycrystals to rotate azimuthally along and about the filament axis so as to generate macroscopically isotropic behavior. By contrast Bi2223 shows only a uniaxial (FWHM <15°) c-axis texture perpendicular to the tape plane without any in-plane texture. Consistent with these observations, a marked, field-increasing, field-decreasing Jc(H) hysteresis characteristic of weak-linked systems appears in Bi2223 but is absent in Bi2212 round wire. Growth-induced texture on cooling from the melt step of the Bi2212 Jc optimization process appears to be the key step in generating this highly desirable microstructure.

  18. Comparison of growth texture in round Bi2212 and flat Bi2223 wires and its relation to high critical current density development

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

    Kametani, F.; Jiang, J.; Matras, M.; Abraimov, D.; Hellstrom, E. E.; Larbalestier, D. C.

    2015-02-10

    Why Bi₂Sr₂CaCu₂Ox (Bi2212) allows high critical current density Jc in round wires rather than only in the anisotropic tape form demanded by all other high temperature superconductors is important for future magnet applications. Here we compare the local texture of state-of-the-art Bi2212 and Bi2223 ((Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀), finding that round wire Bi2212 generates a dominant a-axis growth texture that also enforces a local biaxial texture (FWHM <15°) while simultaneously allowing the c-axes of its polycrystals to rotate azimuthally along and about the filament axis so as to generate macroscopically isotropic behavior. By contrast Bi2223 shows only a uniaxial (FWHM <15°) c-axis texturemore » perpendicular to the tape plane without any in-plane texture. Consistent with these observations, a marked, field-increasing, field-decreasing Jc(H) hysteresis characteristic of weak-linked systems appears in Bi2223 but is absent in Bi2212 round wire. Growth-induced texture on cooling from the melt step of the Bi2212 Jc optimization process appears to be the key step in generating this highly desirable microstructure.« less

  19. AeroSys: Noncompliance Determination (2010-SE-0302) | Department...

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

    Noncompliance Determination (2010-SE-0302) AeroSys: Noncompliance Determination (2010-SE-0302) April 13, 2010 DOE issued a Notice of Noncompliance Determination to AeroSys, Inc. ...

  20. SeQuential Pacific Biodiesel LLC | Open Energy Information

    Open Energy Info (EERE)

    Pacific Biodiesel LLC Jump to: navigation, search Name: SeQuential-Pacific Biodiesel LLC Place: Oregon Sector: Biofuels Product: JV between SeQuential Biofuels, Pacific Biodiesel,...

  1. 2009 Archives-News-PHaSe-EFRC

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

    09 Archives U.S. DOE Announces Energy Frontier Research Centers (08/2009) UMass Amherst EFRC Proposal (08/2009) EFRC Funding Distributed to Successful Centers (08/2009) PHaSE co-director Paul Lahti led off a set of presentations organized by the UMass Amherst Research & Liaison office to meet with a delegation of scientists from various technical research centers of the Gipuzkoa province in the Basque region of northern Spain. The delegation was organized through the Tecnalia Corporation,

  2. 2012 Archives-News-PHaSe-EFRC

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

    2 Archives Tom Russell photo Joint work by Tom Russell, Alex Briseno, and coworkers describes fabrication and a significant degree of device optimization of a low band polymer pDPP/PCBM solar cell, in an article published in Advanced Materials. Photoconversion efficiency up to 5.6% with a fill factor of 60% were obtained. Morphology control based on solvent mixture tuning was critically important for best electrical output. [read more] PHaSE members D. Venkataraman and Tom Russell have edited a

  3. Synthesis and optical study of green light emitting polymer coated CdSe/ZnSe core/shell nanocrystals

    SciTech Connect (OSTI)

    Tripathi, S.K.; Sharma, Mamta

    2013-05-15

    Highlights: ► Synthesis of Polymer coated core CdSe and CdSe/ZnSe core/shell NCs. ► From TEM image, the spherical nature of CdSe and CdSe/ZnSe is obtained. ► Exhibiting green band photoemission peak at 541 nm and 549 nm for CdSe core and CdSe/ZnSe core/shell NCs. ► The shell thickness has been calculated by using superposition of quantum confinement energy model. - Abstract: CdSe/ZnSe Core/Shell NCs dispersed in PVA are synthesized by chemical method at room temperature. This is characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV/Vis spectra and photoluminescence spectroscopy (PL). TEM image shows the spherical nature of CdSe/ZnSe core/shell NCs. The red shift of absorption and emission peak of CdSe/ZnSe core/shell NCs as compared to CdSe core confirmed the formation of core/shell. The superposition of quantum confinement energy model is used for calculation of thickness of ZnSe shell.

  4. Inorganic resins for clinical use of .sup.213Bi generators

    DOE Patents [OSTI]

    DePaoli, David W. (Knoxville, TN); Hu, Michael Z. (Knoxville, TN); Mirzadeh, Saed (Knoxville, TN); Clavier, John W. (Elizabethton, TN)

    2011-03-29

    Applicant's invention is a radionuclide generator resin material for radiochemical separation of daughter radionuclides, particularly .sup.213Bi, from a solution of parental radionuclides, the resin material capable of providing clinical quantities of .sup.213Bi of at least 20-mCi, wherein the resin material comprises a silica-based structure having at least one bifunctional ligand covalently attached to the surface of the silica-based structure. The bifunctional ligand comprises a chemical group having desirable surface functionality to enable the covalent attachment of the bifunctional ligand thereon the surface of the structure and the bifunctional ligand further comprises a second chemical group capable of binding and holding the parental radionuclides on the resin material while allowing the daughter radionuclides to elute off the resin material. The bifunctional ligand has a carbon chain with a limited number of carbons to maintain radiation stability of the resin material.

  5. Recent development of Bi(2223)/Ag tapes for practical applications

    SciTech Connect (OSTI)

    Grasso, G.; Siri, A.S.; Marti, F.; Huang, Y.; Fluekiger, R.; Caracino, P.; Martini, L.

    1999-04-20

    In this paper the authors report about some of the major developments of Ag sheathed Bi(2223) tapes that are actually under study in view of a possible practical application of these conductors. Efforts on improving the tape behavior in presence of alternating currents and high magnetic fields have to be done together with a severe optimization of the Powder-In-Tube method. A clear reduction of the magnetic AC losses is observed by AC susceptibility measurements performed on twisted Bi(2223) tapes prepared at the University of Geneva, with a resistive barrier capable of reducing the coupling losses between filaments. Finally, the authors report on multifilamentary tapes developed with a special configuration that can be of great interest when a magnetic field is applied to the tape at a significant angle with respect to the a-b planes of the superconductor.

  6. Superconductivity in layered BiS2-based compounds

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

    Yazici, D.; Jeon, I.; White, B. D.; Maple, M. B.

    2015-02-25

    Here, a novel family of superconductors based on BiS2-based superconducting layers were discovered in 2012. In short order, other BiS2-based superconductors with the same or related crystal structures were discovered with superconducting critical temperatures Tc of up to 10 K. Many experimental and theoretical studies have been carried out with the goal of establishing the basic properties of these new materials and understanding the underlying mechanism for superconductivity. In this selective review of the literature, we distill the central discoveries from this extensive body of work, and discuss the results from different types of experiments on these materials within themore » context of theoretical concepts and models.« less

  7. Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy

    SciTech Connect (OSTI)

    Loganathan, Muthukumaran; Bristow, Douglas A.

    2014-04-15

    This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

  8. Non-Precious Metal Bi-Functional Catalysts

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

    Precious Metal Bi-Functional Catalysts Paul Matter, PhD pH Matter, LLC June 8, 2015 1 This presentation does not contain any proprietary, confidential, or otherwise restricted information Project ID: DE-SC0013111 2 Company Background  Small Business, founded in 2010, located in Columbus, OH  Equipment for catalyst and fuel cell development  Nearby Ohio State University characterization facilities  Mission: to develop and commercialize catalyst-based products for alternative energy

  9. Combined effects of Bi deficiency and Mn substitution on the structural transformation and functionality of BiFeO{sub 3} films

    SciTech Connect (OSTI)

    Chen, Jingyi; Wang, Yao Deng, Yuan

    2014-11-07

    Mn-doped BiFeO{sub 3} films with Mn contents of 5 and 10 mol. % were prepared via a chemical route. A carefully controlled amount of Bi deficiency was introduced to further tune the lattice structure and the functionality of multiferroic BiFeO{sub 3}. The crystal structure of Bi{sub 1−δ}Fe{sub 1−x}Mn{sub x}O{sub 3} films was investigated by X-ray diffraction and Raman spectra; a rhombohedral-to-orthorhombic phase transition was revealed. The observed double hysteresis loops and two capacitance maxima from polarization vs electric field and capacitance-voltage measurements indicate an antiferroelectric-like behavior. Additionally, the coexistence of ferroelectric (FE) and antiferroelectric (AFE) phases in Bi{sub 1−δ}Fe{sub 1−x}Mn{sub x}O{sub 3} films was revealed from the domain structures obtained by piezoelectric force microscopy. The effects of Mn substitution in conjunction with Bi deficiency on the FE-AFE phase transition and electrical behavior of BiFeO{sub 3} films are discussed in detail. Meanwhile, magnetic and photoluminescence measurements on the films illustrate that Mn substitution gives rise to the net magnetic moment and the defects induced by both Bi deficiency and Mn substitution influence the electronic structure of BiFeO{sub 3} films. This study thus shows a simple and effective way to control the functionalities of BiFeO{sub 3} films.

  10. Method And Apparatus For Production Of Bi-213 From The Activity Ac-225 Source

    DOE Patents [OSTI]

    Egorov, Oleg B.; O'Hara, Matthew J.

    2005-12-06

    A method and apparatus for isolating and purifying a .sup.213 Bi radioactive isotope from an .sup.225 Ac source using a primary column and a primary sorbent which preferentially retains .sup.225 Ac over .sup.213 Bi when exposed to a compatible solvent in combination with a secondary column having a secondary sorbent which retains .sup.213 Bi when exposed to a mixture of the compatible solvent and .sup.213 Bi. A "compatible solvent" is a solvent which will preferentially remove .sup.213 Bi radioactive isotopes from a primary sorbent without removing .sup.225 Ac radioactive isotopes, and then allow .sup.213 Bi radioactive isotopes removed from the primary sorbent to be retained on a secondary sorbent, without having to dilute or otherwise chemically or physically modify the compatible solvent in between exposure to the primary and secondary sorbents.

  11. Carbon quantum dots coated BiVO{sub 4} inverse opals for enhanced photoelectrochemical hydrogen generation

    SciTech Connect (OSTI)

    Nan, Feng; Shen, Mingrong; Fang, Liang E-mail: lfang@suda.edu.cn; Kang, Zhenhui E-mail: lfang@suda.edu.cn; Wang, Junling

    2015-04-13

    Carbon quantum dots (CQDs) coated BiVO{sub 4} inverse opal (io-BiVO{sub 4}) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO{sub 4} maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO{sub 4} to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO{sub 4} exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO{sub 4} thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

  12. Non-Ideal p-n junction Diode of Sb{sub x}Se{sub 1-x}(x = 0.4, 0.5, 0.6, 0.7) Thin Films

    SciTech Connect (OSTI)

    Mustafa, Falah I.; Gupta, Shikha; Goyal, N.; Tripathi, S. K.

    2011-12-12

    We have made diodes consisting of the same alloy i.e. Sb{sub x}Se{sub 1-x}(x = 0.4, 0.5, 0.6 and 0.7), but change the concentration of Sb metal from 40% to 70% atomic weight percentage. It is observed from the Hall measurements that the nature of charge carriers have changed from p- to n-type at x = 0.6 for Sb{sub x}Se{sub 1-x}. We have measured I-V characteristics of four p-n junction diodes i.e. p-Sb{sub 2}Se{sub 3}/n-Sb{sub 3}Se{sub 2}, p-Sb{sub 2}Se{sub 3}/n-Sb{sub 7}Se{sub 3}, p-SbSe/n-Sb{sub 3}Se{sub 2}, p-SbSe/n-Sb{sub 7}Se{sub 3}. From the I-V plots we have calculated the parameters as built-in voltage (V{sub bi}), forward resistance (R{sub f}), ideal factor (n), saturation current (I{sub o}), breakdown current (I{sub Bd}) and breakdown voltage (V{sub Bd}).

  13. Waiver of the Bi-Weekly Pay L:imitation for Emergency Response Activities |

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

    Department of Energy Waiver of the Bi-Weekly Pay L:imitation for Emergency Response Activities Waiver of the Bi-Weekly Pay L:imitation for Emergency Response Activities Heads of Departmental elements, with the concurrence of their servicing Human Resources staff, are authorized to waive the bi-weekly pay limitation for employees engaged in emergency response activities that include, but are not limited to, disaster relief assistance, radiological assistance, and terrorist attacks. This

  14. Microsoft Word - BiT on NGO draft 05[1].doc

    Office of Scientific and Technical Information (OSTI)

    ... theory calculations indicate that the creation of an additional Co electronic state ... structure evolution with Co incorporation into BiT depending on the strain state. ...

  15. Efficient removal rhodamine B over hydrothermally synthesized fishbone like BiVO{sub 4}

    SciTech Connect (OSTI)

    Lin, Xue; Li, Hongji; Yu, Lili; Zhao, Han; Yan, Yongsheng; Liu, Chunbo; Zhai, Hongjv

    2013-10-15

    Graphical abstract: - Highlights: Fishbone like BiVO{sub 4} product was synthesized through hydrothermal method. BiVO{sub 4} sample was characterized by various characterization technologies. Fishbone like BiVO{sub 4} presented outstanding photocatalytic performance. - Abstract: Fishbone like BiVO{sub 4} product has been successfully synthesized by a hydrothermal method without using any surfactant or template. The pH value was found to play an important role in the formation of this morphology. The band gap of the as-prepared fishbone like BiVO{sub 4} sample was estimated to be about 2.36 eV from the onset of UVvis diffuse reflectance spectrum (UVvis DRS) of the photocatalyst. The as-prepared fishbone like BiVO{sub 4} sample exhibited excellent visible-light-driven photocatalytic efficiency. Over this catalyst, the 100% degradation of rhodamine B (Rh B) (0.005 mmol L{sup ?1}) was obtained after visible light irradiation (? > 420 nm) for 180 min. This is much higher than that of bulk BiVO{sub 4} sample prepared by solid-state reaction. The reason for the differences in the photocatalytic activities of fishbone like BiVO{sub 4} sample and bulk BiVO{sub 4} sample was further investigated.

  16. SE-MA-NO Electric Coop | Open Energy Information

    Open Energy Info (EERE)

    SE-MA-NO Electric Coop Jump to: navigation, search Name: SE-MA-NO Electric Coop Place: Missouri Phone Number: (417) 924-3291 Website: www.semano.com Facebook: https:...

  17. TiO{sub 2}/Bi{sub 2}(BDC){sub 3}/BiOCl nanoparticles decorated ultrathin nanosheets with excellent photocatalytic reaction activity and selectivity

    SciTech Connect (OSTI)

    Zhou, Shu-Mei; Ma, De-Kun Cai, Ping; Chen, Wei; Huang, Shao-Ming

    2014-12-15

    Graphical abstract: TiO{sub 2}/Bi{sub 2}(BDC){sub 3}/BiOCl nanoparticles decorated ultrathin nanosheets showed excellent photocatalytic reaction activity and selectivity. - Highlights: • TiO{sub 2}/Bi{sub 2}(BDC){sub 3}/BiOCl nanoparticles decorated ultrathin nanosheets were synthesized through a facile hydrothermal process. • The products showed excellent photocatalytic activities for the degradation of various dyes. • The photocatalytic activities of the composite materials could be easily adjusted through tuning the content of TiO{sub 2}. • TiO{sub 2}/Bi{sub 2}(BDC){sub 3}/BiOCl displayed obvious photocatalytic selectivity in mixed dyes systems of rhodamine B and eosin Y. - Abstract: Photocatalysts with excellent photocatalytic reaction activity and ideal selectivity are highly desirable for pollutants clearance and purification of targeted organics from a mixture. Continued efforts toward the goal, we here present a facile hydrothermal route to synthesize TiO{sub 2}/Bi-benzenedicarboxylate/BiOCl nanoparticles decorated ultrathin nanosheets with a thickness less than 5 nm on a large scale. The as-synthesized products showed excellent photocatalytic activities for the degradation of various dyes such as rhodamine B, eosin Y and methylene blue in aqueous solution under visible light irradiation. The photocatalytic activities of TiO{sub 2}/Bi-benzenedicarboxylate/BiOCl nanocomposites for the degradation of rhodamine B and eosin Y could be adjusted through tuning the content of TiO{sub 2}. With increasing the amount of TiO{sub 2}, the composites showed declining photocatalytic activities in decomposing of rhodamine B while on the contrary they displayed enhanced photocatalytic activities in decomposing of eosin Y. Interestingly, TiO{sub 2}/Bi-benzenedicarboxylate/BiOCl composite nanosheets showed obvious photocatalytic selectivity in a mixed dyes system. The photocatalytic reaction and selectivity mechanisms of the nanocomposites for the degradation of the

  18. MgSe/ZnSe/CdSe coupled quantum wells grown on InP substrate with intersubband absorption covering 1.55??m

    SciTech Connect (OSTI)

    Chen, Guopeng; Shen, Aidong; De Jesus, Joel; Tamargo, Maria C.

    2014-12-08

    The authors report the observation of intersubband (ISB) transitions in the optical communication wavelength region in MgSe/ZnSe/CdSe coupled quantum wells (QWs). The coupled QWs were grown on InP substrates by molecular beam epitaxy. By inserting ZnSe layers to compensate the strain, samples with high structural quality were obtained, as indicated by well resolved satellite peaks in high-resolution x-ray diffraction. The observed ISB transition energies agree well with the calculated values.

  19. Goodman Manufacturing: Order (2011-SE-4301) | Department of Energy

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

    Goodman Manufacturing: Order (2011-SE-4301) Goodman Manufacturing: Order (2011-SE-4301) March 2, 2012 DOE ordered Goodman Manufacturing Company, L.P., to pay a $14,800 civil penalty after finding Goodman had manufactured and distributed in commerce in the U.S. at least 74 units of commercial package air conditioner basic model CPC180*. Goodman Manufacturing: Order (2011-SE-4301) (131.78 KB) More Documents & Publications Goodman Manufacturing: Proposed Penalty (2011-SE-4301) Goodman

  20. Barron: Order (2013-SE-5402) | Department of Energy

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

    Order (2013-SE-5402) Barron: Order (2013-SE-5402) March 22, 2016 DOE ordered Barron Lighting Group, Inc. to pay a $22,849 civil penalty after finding Barron had manufactured and distributed in commerce in the U.S. 429 units of various noncompliant metal halide lamp fixtures. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Barron. Barron: Order (2013-SE-5402) (19.24 KB) More Documents & Publications Barron: Noncompliance Determination (2013-SE-5402)

  1. SE-72/AS-72 generator system based on Se extraction/ As reextraction

    DOE Patents [OSTI]

    Fassbender, Michael Ernst; Ballard, Beau D

    2013-09-10

    The preparation of a .sup.72Se/.sup.72As radioisotope generator involves forming an acidic aqueous solution of an irradiated alkali bromide target such as a NaBr target, oxidizing soluble bromide in the solution to elemental bromine, removing the elemental bromine, evaporating the resulting solution to a residue, removing hydrogen chloride from the residue, forming an acidic aqueous solution of the residue, adding a chelator that selectively forms a chelation complex with selenium, and extracting the chelation complex from the acidic aqueous solution into an organic phase. As the .sup.72Se generates .sup.72As in the organic phase, the .sup.72As may be extracted repeatedly from the organic phase with an aqueous acid solution.

  2. Experience with Bi-Fuel LPG Pickups in Texas

    SciTech Connect (OSTI)

    Whalen, P.

    1999-05-12

    The State of Texas requires state agencies to purchase alternative fuel vehicles (AFVs). In 1996, Texas Department of Transportation (TxDOT) representatives added about 400 bi-fuel liquefied petroleum gas (LPG) pickup trucks to their fleet. The fleet managers were willing to share information about their fleets and the operation of these vehicles, so a study was launched to collect operations, maintenance, and cost data for selected LPG and gasoline vehicles (as controls) throughout 18 months of vehicle operation. This case study presents the results of that data collection and its subsequent analysis.

  3. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect (OSTI)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  4. Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy

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

    Li, Xufan; Lin, Ming-Wei; Lin, Junhao; Huang, Bing; Puretzky, Alexander A.; Ma, Cheng; Wang, Kai; Zhou, Wu; Pantelides, Sokrates T.; Chi, Miaofang; et al

    2016-04-01

    Two-dimensional (2D) heterostructures hold the promise for future atomically-thin electronics and optoelectronics due to their diverse functionalities. While heterostructures consisting of different transition metal dichacolgenide monolayers with well-matched lattices and novel physical properties have been successfully fabricated via van der Waals (vdW) or edge epitaxy, constructing heterostructures from monolayers of layered semiconductors with large lattice misfits still remains challenging. Here, we report the growth of monolayer GaSe/MoSe2 heterostructures with large lattice misfit by two-step chemical vapor deposition (CVD). Both vertically stacked and lateral heterostructures are demonstrated. The vertically stacked GaSe/MoSe2 heterostructures exhibit vdW epitaxy with well-aligned lattice orientation between themore » two layers, forming an incommensurate vdW heterostructure. However, the lateral heterostructures exhibit no lateral epitaxial alignment at the interface between GaSe and MoSe2 crystalline domains. Instead of a direct lateral connection at the boundary region where the same lattice orientation is observed between GaSe and MoSe2 monolayer domains in lateral GaSe/MoSe2 heterostructures, GaSe monolayers are found to overgrow MoSe2 during CVD, forming a stripe of vertically stacked vdW heterostructure at the crystal interface. Such vertically-stacked vdW GaSe/MoSe2 heterostructures are shown to form p-n junctions with effective transport and separation of photo-generated charge carriers between layers, resulting in a gate-tunable photovoltaic response. In conclusion, these GaSe/MoSe2 vdW heterostructures should have applications as gate-tunable field-effect transistors, photodetectors, and solar cells.« less

  5. Spectral photoresponse of ZnSe/GaAs(001) heterostructures with CdSe ultra-thin quantum well insertions

    SciTech Connect (OSTI)

    Valverde-Chvez, D. A.; Sutara, F.; Hernndez-Caldern, I.

    2014-05-15

    We present a study of the spectral photoresponse (SPR) of ZnSe/GaAs(001) heterostructures for different ZnSe film thickness with and without CdSe ultra-thin quantum well (UTQW) insertions. We observe a significant increase of the SPR of heterostructures containing 3 monolayer thick CdSe UTQW insertions; these results encourage their use in photodetectors and solar cells.

  6. Twinning effect on photoluminescence spectra of ZnSe nanowires

    SciTech Connect (OSTI)

    Xu, Jing; Wang, Chunrui Wu, Binhe; Xu, Xiaofeng; Chen, Xiaoshuang; Oh, Hongseok; Baek, Hyeonjun; Yi, Gyu-Chul

    2014-11-07

    Bandgap engineering in a single material along the axial length of nanowires may be realized by arranging periodic twinning, whose twin plane is vertical to the axial length of nanowires. In this paper, we report the effect of twin on photoluminescence of ZnSe nanowires, which refers to the bandgap of it. The exciton-related emission peaks of transverse twinning ZnSe nanowires manifest a 10-meV-blue-shift in comparison with those of longitudinal twinning ZnSe nanowires. The blue-shift is attributed to quantum confinement effect, which is influenced severely by the proportion of wurtzite ZnSe layers in ZnSe nanowires.

  7. The role of the isolated 6s states in BiVO{sub 4} on the electronic and atomic structures

    SciTech Connect (OSTI)

    Ma, Jie; Wang, Lin-Wang

    2014-10-27

    BiVO{sub 4} is one of the most promising photoanodes for water-splitting applications. Similar to many d{sup 10} materials, where the full-shell d electrons are not directly involved in the bonding, the Bi 6s electrons form isolated low-energy bands in BiVO{sub 4}. By systematically altering the energy of the Bi 6s states, we find direct evidences that the isolated s states, through the s-p coupling, affect the BiVO{sub 4} properties, including valence band maximum position, charge density, and atomic structural distortion. We find that many good properties of BiVO{sub 4} for water splitting are related to the s-p coupling due to the existence of Bi 6s states. Based on this understanding, we propose that alloying Bi with Sb can enhance these properties, and hence improve the water-splitting efficiency.

  8. Synthesis of BiPbSrCaCuO superconductor

    DOE Patents [OSTI]

    Hults, W.L.; Kubat-Martin, K.A.; Salazar, K.V.; Phillips, D.S.; Peterson, D.E.

    1994-04-05

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi[sub a]Pb[sub b]Sr[sub c]Ca[sub d]Cu[sub e]O[sub f] wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10[+-]z by reacting a mixture of Bi[sub 4]Sr[sub 3]Ca[sub 3]Cu[sub 4]O[sub 16[+-]z], an alkaline earth metal cuprate, e.g., Sr[sub 9]Ca[sub 5]Cu[sub 24]O[sub 41], and an alkaline earth metal plumbate, e.g., Ca[sub 2[minus]x]Sr[sub x]PbO[sub 4] wherein x is about 0.5, is disclosed.

  9. Synthesis of BiPbSrCaCuO superconductor

    DOE Patents [OSTI]

    Hults, William L.; Kubat-Martin, Kimberly A.; Salazar, Kenneth V.; Phillips, David S.; Peterson, Dean E.

    1994-01-01

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

  10. Tape casting and partial melting of Bi-2212 thick films

    SciTech Connect (OSTI)

    Buhl, D.; Lang, T.; Heeb, B.

    1994-12-31

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density of 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).

  11. Electronic structure of the ingredient planes of the cuprate superconductor Bi2Sr2CuO6+δ: A comparison study with Bi2Sr2CaCu2O8+δ

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

    Yan -Feng Lv; Gu, G. D.; Wang, Wen -Lin; Ding, Hao; Wang, Yang; Ding, Ying; Zhong, Ruidan; Schneeloch, John; Wang, Lili; He, Ke; et al

    2016-04-15

    By means of low-temperature scanning tunneling microscopy, we report on the electronic structures of the BiO and SrO planes of the Bi2Sr2CuO6+δ (Bi-2201) superconductor prepared by argon-ion bombardment and annealing. Depending on post annealing conditions, the BiO planes exhibit either a pseudogap (PG) with sharp coherence peaks and an anomalously large gap magnitude of 49 meV or van Hove singularity (vHS) near the Fermi level, while the SrO is always characteristic of a PG-like feature. This contrasts with the Bi2Sr2CaCu2O8+δ (Bi-2212) superconductor where vHS occurs solely on the SrO plane. We disclose the interstitial oxygen dopants (δ in the formulas)more » as a primary cause for the occurrence of vHS, which are located dominantly around the BiO and SrO planes, respectively, in Bi-2201 and Bi-2212. This is supported by the contrasting structural buckling amplitude of the BiO and SrO planes in the two superconductors. Furthermore, our findings provide solid evidence for the irrelevance of PG to the superconductivity in the two superconductors, as well as insights into why Bi-2212 can achieve a higher superconducting transition temperature than Bi-2201, and by implication, the mechanism of cuprate superconductivity.« less

  12. Inkjet Printed Metallizations for Cu(In1-xGax)Se2 Photovoltaic Cells

    SciTech Connect (OSTI)

    Hersh, P. A.; Curtis, C. J.; van Hest, M. F. A. M.; Kreuder, J. J.; Pasquarelli, R.; Miednaer, A.; Ginley, D. S.

    2011-12-01

    This study reports the inkjet printing of Ag front contacts on Aluminum doped Zinc Oxide (AZO)/intrinsic Zinc Oxide (i-ZnO)/CdS/Cu(In{sub 1-x}Ga{sub x})Se{sub 2} (CIGS)/Mo thin film photovoltaic cells. The printed Ag contacts are being developed to replace the currently employed evaporated Ni/Al bi-layer contacts. Inkjet deposition conditions were optimized to reduce line resistivity and reduce contact resistance to the Al:ZnO layer. Ag lines printed at a substrate temperature of 200 C showed a line resistivity of 2.06 {mu}{Omega} {center_dot} cm and a contact resistance to Al:ZnO of 8.2 {+-} 0.2 m{Omega} {center_dot} cm{sup 2} compared to 6.93 {+-} 0.3 m{Omega} {center_dot} cm{sup 2} for thermally evaporated contacts. These deposition conditions were used to deposit front contacts onto high quality CIGS thin film photovoltaic cells. The heating required to print the Ag contacts caused the performance to degrade compared to similar devices with evaporated Ni/Al contacts that were not heated. Devices with inkjet printed contacts showed 11.4% conversion efficiency compared to 14.8% with evaporated contacts. Strategies to minimize heating, which is detrimental for efficiency, during inkjet printing are proposed.

  13. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

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

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have notmore » been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.« less

  14. Structural and ferromagnetic properties of an orthorhombic phase of MnBi stabilized with Rh additions

    SciTech Connect (OSTI)

    Taufour, Valentin; Thimmaiah, Srinivasa; March, Stephen; Saunders, Scott; Sun, Kewei; Lamichhane, Tej Nath; Kramer, Matthew J.; Bud’ko, Sergey L.; Canfield, Paul C.

    2015-07-28

    The article addresses the possibility of alloy elements in MnBi which may modify the thermodynamic stability of the NiAs-type structure without significantly degrading the magnetic properties. The addition of small amounts of Rh and Mn provides an improvement in the thermal stability with some degradation of the magnetic properties. The small amounts of Rh and Mn additions in MnBi stabilize an orthorhombic phase whose structural and magnetic properties are closely related to the ones of the previously reported high-temperature phase of MnBi (HT MnBi). The properties of the HT MnBi, which is stable between 613 and 719 K, have not been studied in detail because of its transformation to the stable low-temperature MnBi (LT MnBi), making measurements near and below its Curie temperature difficult. The Rh-stabilized MnBi with chemical formula Mn1.0625–xRhxBi [x=0.02(1)] adopts a new superstructure of the NiAs/Ni2In structure family. It is ferromagnetic below a Curie temperature of 416 K. The critical exponents of the ferromagnetic transition are not of the mean-field type but are closer to those associated with the Ising model in three dimensions. The magnetic anisotropy is uniaxial; the anisotropy energy is rather large, and it does not increase when raising the temperature, contrary to what happens in LT MnBi. The saturation magnetization is approximately 3μB/f.u. at low temperatures. Thus, while this exact composition may not be application ready, it does show that alloying is a viable route to modifying the stability of this class of rare-earth-free magnet alloys.

  15. Thermoelectric transport of Se-rich Ag{sub 2}Se in normal phases and phase transitions

    SciTech Connect (OSTI)

    Mi, Wenlong; Lv, Yanhong; Qiu, Pengfei; Shi, Xun E-mail: cld@mail.sic.ac.cn; Chen, Lidong E-mail: cld@mail.sic.ac.cn; Zhang, Tiansong

    2014-03-31

    Small amount of Se atoms are used to tune the carrier concentrations (n{sub H}) and electrical transport in Ag{sub 2}Se. Significant enhancements in power factor and thermoelectric figure of merit (zT) are observed in the compositions of Ag{sub 2}Se{sub 1.06} and Ag{sub 2}Se{sub 1.08}. The excessive Se atoms do not change the intrinsically electron-conducting character in Ag{sub 2}Se. The detailed analysis reveals the experiment optimum carrier concentration in Ag{sub 2}Se is around 5??10{sup 18}?cm{sup ?3}. We also investigate the temperature of maximum zT and the thermoelectric transport during the first order phase transitions using the recently developed measurement system.

  16. Confined lattice dynamics of single and quadruple SnSe bilayers in [(SnSe) 1.04 ] m [MoSe 2 ] n ferecrystals

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

    Klobes, Benedikt; Hu, Michael Y.; Beekman, Matt; Johnson, David C.; Hermann, Raphaël P.

    2015-11-30

    The Sn specific densities of phonon states in the SnSe subunits of [(SnSe)1.04]m[MoSe2]n ferecrystals with (m,n) = (1,1), (4,1) and in bulk SnSe were derived from nuclear inelastic scattering by the 119Sn M ssbauer resonance. When using different measurement configurations, phonons with polarization parallel and perpendicular to the ferecrystal plane were specifically probed. Vibrational properties and phonon spectral weight are found to strongly depend on the phonon polarization and layer count m. Moreover, a highly peculiar feature of these ferecrystal densities of phonon states is the emergence of rather sharp high energy vibrational modes polarized perpendicular to the ferecrystal plane,more » which contrasts with usual findings in thin layered structures and nanostructured materials in general, and a depletion of modes with a gap appearing between acoustic and high energy modes. The spectral weight of these phonons depends on the overall SnSe content, m, but cannot be unambiguously attributed to SnSe MoSe2 interfaces. Considering the low energy part of lattice dynamics, ferecrystals exhibit rather low average phonon group velocities as compared to the speed of sound in the long wavelength limit. For the (1,1) ferecrystal, this effect is most pronounced for vibrations polarized in the ferecrystal plane. Therefore, an experimental microscopic origin for the vibrational and bonding anisotropy in subunits of ferecrystals is provided.« less

  17. CuInSe/sub 2/-based photoelectrochemical cells: their use in characterization of thin CuInSe/sub 2/ films, and as photovoltaic cells per se

    SciTech Connect (OSTI)

    Cahen, D.; Chen, Y.W.; Ireland, P.J.; Noufi, R.; Turner, J.A.; Rincon, C.; Bachmann, K.J.

    1984-05-01

    Photoelectrochemistry has been employed to characterize the p-CuInSe/sub 2/ component of the CdS/CuInSe/sub 2/ on-metal and a nonaqueous electrolyte containing a redox couple not specifically adsorbed onto the semiconductor, we can test the films for photovoltaic activity and obtain effective electronic properties of them, before CdS deposition, in a nondestructive manner. Electrochemical decomposition of CuInSe/sub 2/ was investigated in acetonitrile solutions to determine the mechanism of decomposition (n and p) in the dark and under illumination. Electrochemical, solution chemical and surface analyses confirmed at the light-assisted decomposition of CuInSe/sub 2/ resulted in metal ions and elemental chalcogen. On the basis of the results from the electrochemical decomposition, and studies on the solid state chemistry of the (Cu/sub 2/Se)/sub x/(In/sub 2/Se/sub 3/)/sub 1-x/ system and surface analyses, the CuInSe/sub 2//polyiodide interface was stabilized and up to 11.7% conversion efficiencies were obtained.

  18. Effect of Composition and Heat Treatment on MnBi Magnetic Materials

    SciTech Connect (OSTI)

    Cui, Jun; Choi, Jung-Pyung; Polikarpov, Evgueni; Bowden, Mark E.; Xie, Wei; Li, Guosheng; Nie, Zimin; Zarkevich, Nikolai; Kramer, Matthew J.; Johnson, Duane D.

    2014-08-17

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material. Compare to other rare-earth-free candidates, MnBi stands out for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. Several groups have demonstrated that the Hci of MnBi compound in thin film or in powder form can exceed 12 kOe and 26 kOe at 300 K and 523 K, respectively. Such steep increase in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. The reaction between Mn and Bi is peritectic, so Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, the composition of the Mn-Bi alloy with the largest amount of the desired LTP (low temperature phase) MnBi and highest saturation magnetization will be over-stoichiometric and rich in Mn. The amount of additional Mn required to compensate the Mn precipitation depends on solidification rate: the faster the quench speed, the less Mn precipitates. Here we report a systematic study of the effect of composition and heat treatments on the phase contents and magnetic properties of Mn-Bi alloys. In this study, Mn-Bi alloys with 14 compositions were prepared using conventional metallurgical methods such as arc melting and vacuum heat treatment, and the obtained alloys were analyzed for compositions, crystal structures, phase content, and magnetic properties. The results show that the composition with 55 at.% Mn exhibits the highest LTP MnBi content and the highest magnetization. The sample with this composition shows >90 wt.% LTP MnBi content. Its measured saturation magnetization is 68 emu/g with 2.3 T applied field at 300 K; its coercivity is 13 kOe and its energy product is 12 MGOe at 300 K. A bulk magnet fabricated using this powder exhibits an energy product of 8.2 MGOe.

  19. Perlick: Agreement (2010-SE-0109) | Department of Energy

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

    Perlick: Agreement (2010-SE-0109) Perlick: Agreement (2010-SE-0109) February 7, 2011 DOE and Perlick Residential & Hospitality Products entered into a Compromise Agreement in which Perlick agreed to pay a $5,000 civil penalty after DOE found that Perlick had manufactured and distributed in commerce in the U.S. model HP72ROO-S, a noncompliant refrigerator. The Compromise Agreement reflected the settlement terms between DOE and Perlick. Perlick: Agreement (2010-SE-0109) (240.67 KB) More

  20. SeQuential Biofuels LLC | Open Energy Information

    Open Energy Info (EERE)

    Biofuels LLC Jump to: navigation, search Name: SeQuential Biofuels LLC Place: Portland, Oregon Zip: 97231 Sector: Biofuels Product: A biofuels marketing and distribution company...

  1. Research Forum Schedule-Research-PHaSe-EFRC

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

    Research Forum Schedule PHaSE Research Fora and Talks This webpage is provided for legacy archive purposes only, as of 30 April 2015.

  2. SE Idaho Load Service Update - June 10, 2015

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

    SE-Idaho-Load-Service-Update---June-10,-2015 Sign In About | Careers | Contact | Investors | bpa.gov Search Doing Business Expand Doing Business Customer Involvement Expand...

  3. U-105:Oracle Java SE Critical Patch Update Advisory

    Broader source: Energy.gov [DOE]

    Multiple vulnerabilities were reported in Oracle Java SE. A remote user can execute arbitrary code on the target system. A remote user can cause denial of service conditions.

  4. Size dependent structural, vibrational and magnetic properties of BiFeO{sub 3} and core-shell structured BiFeO{sub 3}@SiO{sub 2} nanoparticles

    SciTech Connect (OSTI)

    Chauhan, Sunil Kumar, Manoj Chhoker, Sandeep Katyal, S. C.

    2014-04-24

    Bulk BiFeO{sub 3}, BiFeO{sub 3} nanoparticles and core-shell structured BiFeO{sub 3}@SiO{sub 2} nanoparticles were synthesized by solid state reaction method, sol-gel and Stöber process (SiO{sub 2} shell) respectively. Transmission electron microscopy image confirmed the core-shell structure of BiFeO{sub 3}@SiO{sub 2} nanoparticles with BiFeO3 core ∼50-90 nm and SiO{sub 2} shell ∼16 nm. X-ray diffraction and FTIR spectroscopy results showed the presence of distorted rhombohedral structure with R3c space group in all three samples. The magnetic measurement indicated the existence of room-temperature weak ferromagnetism in core-shell BiFeO{sub 3}@SiO{sub 2} nanoparticles and BiFeO3 nanoparticles, whereas bulk BiFeO{sub 3} showed antiferromagnteic nature. Electron Spin Resonance results confirmed the enhancement in magnetic properties of coreshell structured BiFeO{sub 3}@SiO{sub 2} nanoparticles in comparison with BiFeO{sub 3} nanoparticles and bulk BiFeO{sub 3}.

  5. A novel Bi-based phosphomolybdate photocatalyst K{sub 2}Bi(PO{sub 4})(MoO{sub 4}): Crystal structure, electronic structure and photocatalytic activity

    SciTech Connect (OSTI)

    Huang, Hongwei; Chen, Gong; Wang, Shuobo; Kang, Lei; Lin, Zheshuai; Zhang, Yihe

    2014-03-01

    Graphical abstract: - Highlights: A new type of phosphomolybdate K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) photocatalyst was successfully synthesized. The products synthesized at 600 C were mainly composed of nano-cubes. The indirect band gap of K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) has been determined to be 2.93 eV. K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) synthesized at 600 C exhibits the highest photocatalytic activity. The electronic structure was calculated by density functional calculations. - Abstract: A novel phosphomolybdate photocatalyst K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) has been successfully developed via a solid-state reaction. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectra. The photocatalytic activities of the samples prepared at different temperature were determined by the photooxidative decomposition of methylene blue (MB) in aqueous solution. The results revealed that K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) can be used as an effective photocatalyst under UVvis irradiation and the nanocubes obtained at 600 C exhibits the highest photocatalytic activity. The photodegradation of MB by K{sub 2}Bi(PO{sub 4})(MoO{sub 4}) nanocrystals followed the first-order kinetics. Theoretical calculations on electronic structure confirmed the indirect optical transitions property in the absorption edge region of K{sub 2}Bi(PO{sub 4})(MoO{sub 4}), and the orbital constitutions of CB and VB were also analyzed.

  6. Evidence against a charge density wave on Bi(111)

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

    Kim, T. K.; Wells, J.; Kirkegaard, C.; Li, Z.; Hoffmann, S. V.; Gayone, J. E.; Fernandez-Torrente, I.; Häberle, P.; Pascual, J. I.; Moore, K. T.; et al

    2005-08-18

    The Bi(111) surface was studied by scanning tunneling microscopy (STM), transmission electron microscopy (TEM) and angle-resolved photoemission (ARPES) in order to verify the existence of a recently proposed surface charge density wave (CDW). The STM and TEM results to not support a CDW scenario at low temperatures. Thus the quasiparticle interference pattern observed in STM confirms the spin-orbit split character of the surface states which prevents the formation of a CDW, even in the case of good nesting. The dispersion of the electronic states observed with ARPES agrees well with earlier findings. In particular, the Fermi contour of the electronmore » pocket at the centre of the surface Brillouin zone is found to have a hexagonal shape. However, no gap opening or other signatures of a CDW phase transition can be found in the temperature-dependent data.« less

  7. Evidence against a charge density wave on Bi(111)

    SciTech Connect (OSTI)

    Kim, T. K.; Wells, J.; Kirkegaard, C.; Li, Z.; Hoffmann, S. V.; Gayone, J. E.; Fernandez-Torrente, I.; Häberle, P.; Pascual, J. I.; Moore, K. T.; Schwartz, A. J.; He, H.; Spence, J. C. H.; Downing, K. H.; Lazar, S.; Tichelaar, F. D.; Borisenko, S. V.; Knupfer, M.; Hofmann, Ph.

    2005-08-18

    The Bi(111) surface was studied by scanning tunneling microscopy (STM), transmission electron microscopy (TEM) and angle-resolved photoemission (ARPES) in order to verify the existence of a recently proposed surface charge density wave (CDW). The STM and TEM results to not support a CDW scenario at low temperatures. Thus the quasiparticle interference pattern observed in STM confirms the spin-orbit split character of the surface states which prevents the formation of a CDW, even in the case of good nesting. The dispersion of the electronic states observed with ARPES agrees well with earlier findings. In particular, the Fermi contour of the electron pocket at the centre of the surface Brillouin zone is found to have a hexagonal shape. However, no gap opening or other signatures of a CDW phase transition can be found in the temperature-dependent data.

  8. CdSe self-assembled quantum dots with ZnCdMgSe barriers emitting throughout the visible spectrum

    SciTech Connect (OSTI)

    Perez-Paz, M. Noemi; Zhou Xuecong; Munoz, Martin; Lu Hong; Sohel, Mohammad; Tamargo, Maria C.; Jean-Mary, Fleumingue; Akins, Daniel L.

    2004-12-27

    Self-assembled quantum dots of CdSe with ZnCdMgSe barriers have been grown by molecular beam epitaxy on InP substrates. The optical and microstructural properties were investigated using photoluminescence (PL) and atomic force microscopy (AFM) measurements. Control and reproducibility of the quantum dot (QD) size leading to light emission throughout the entire visible spectrum range has been obtained by varying the CdSe deposition time. Longer CdSe deposition times result in a redshift of the PL peaks as a consequence of an increase of QD size. AFM studies demonstrate the presence of QDs in uncapped structures. A comparison of this QD system with CdSe/ZnSe shows that not only the strain but also the chemical properties of the system play an important role in QD formation.

  9. Effect of composition and heat treatment on MnBi magnetic materials

    SciTech Connect (OSTI)

    Cui, Jun [Pacific Northwest National Laboratory; Choi, Jung-Pyung [Pacific Northwest National Laboratory; Polikarpov, Evgueni [Pacific Northwest National Laboratory; Bowden, Mark E [Pacific Northwest National Laboratory; Xie, Wei [Pacific Northwest National Laboratory; Li, Guosheng [Pacific Northwest National Laboratory; Nie, Zimin [Pacific Northwest National Laboratory; Zarkevich, Nikolai [Ames Laboratory; Kramer, Matthew J [Ames Laboratory; Johnson, Duane [Ames Laboratory

    2014-10-01

    The metallic compound MnBi is a promising rare-earth-free permanent magnet material, unique among all candidates for its high intrinsic coercivity (Hci) and its large positive temperature coefficient. The Hci of MnBi in thin-film or powder form can exceed 12 and 26 kOe at 300 and 523 K, respectively. Such a steep rise in Hci with increasing temperature is unique to MnBi. Consequently, MnBi is a highly sought-after hard phase for exchange coupling nanocomposite magnets. However, the reaction between Mn and Bi is peritectic, and hence Mn tends to precipitate out of the MnBi liquid during the solidification process. As result, when the alloy is prepared using conventional induction or arc-melting casting methods, additional Mn is required to compensate the precipitation of Mn. In addition to composition, post-casting annealing plays an important role in obtaining a high content of MnBi low-temperature phase (LTP) because the annealing encourages the Mn precipitates and the unreacted Bi to react, forming the desired LTP phase. Here we report a systematic study of the effect of composition and heat treatments on the phase content and magnetic properties of MnBi alloys. In this study, 14 compositions were prepared using conventional metallurgical methods, and the compositions, crystal structures, phase content and magnetic properties of the resulting alloys were analyzed. The results show that the composition with 55 at.% Mn exhibits both the highest LTP content (93 wt.%) and magnetization (74 emu g?1 with 9 T applied field at 300 K).

  10. Electronic structure and photovoltaic application of BiI{sub 3}

    SciTech Connect (OSTI)

    Lehner, Anna J.; Wang, Hengbin; Fabini, Douglas H.; Liman, Christopher D.; Perry, Erin E.; Chabinyc, Michael L.; Hébert, Claire-Alice; Wang, Ming; Bazan, Guillermo C.; and others

    2015-09-28

    Rapid recent improvement in photovoltaic efficiency in hybrid lead halide perovskite materials has provided the impetus for understanding other, related main-group halide systems. Here, we show that the closely related but less toxic bismuth iodide BiI{sub 3} can show promising optoelectronic properties. Layered binary BiI{sub 3} is used here as the active layer in planar solar cell architectures (efficiency approximately 0.3%). Experimental and computational studies of absolute band positions of BiI{sub 3} are also presented, to help in the rational design of device architectures that would allow efficient charge transfer at the interfaces.

  11. Electron-hole asymmetry, Dirac fermions, and quantum magnetoresistance in BaMnBi2

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

    Li, Lijun; Wang, Kefeng; Graf, D.; Wang, Limin; Wang, Aifeng; Petrovic, C.

    2016-03-28

    Here, we report two-dimensional quantum transport and Dirac fermions in BaMnBi2 single crystals. BaMnBi2 is a layered bad metal with highly anisotropic conductivity and magnetic order below 290 K. Magnetotransport properties, nonzero Berry phase, small cyclotron mass, and the first-principles band structure calculations indicate the presence of Dirac fermions in Bi square nets. Quantum oscillations in the Hall channel suggest the presence of both electron and hole pockets, whereas Dirac and parabolic states coexist at the Fermi level.

  12. Tuning electron-electron correlation in noncentrosymmetric superconductor BiPd

    SciTech Connect (OSTI)

    Joshi, Bhanu Thamizhavel, A. Ramakrishnan, S.

    2014-04-24

    In this work, we have successfully tuned the electron-electron correlation in new noncentrosymmertic superconductor (NCS) BiPd via Pb substitution on one of the inequivalent Bi sites present in BiPd and simultaneously keeping the parent noncentrosymmetric crystal structure intact. Heat capacity data is suggesting a fourfold increase in density of states at Fermi level via Pb substitution while superconducting transition temperature has been suppressed. This work will clearly open up a rare chance to study the effect of electron–electron correlation via selective tuning of DOS at Fermi level in NCS.

  13. Photocatalytic and magnetic behaviors observed in nanostructured BiFeO{sub 3} particles

    SciTech Connect (OSTI)

    Li Shun; Lin Yuanhua; Nan Cewen; Wang Yao; Zhang Boping

    2009-03-01

    Nanostructured BiFeO{sub 3} particles have been synthesized by a hydrothermal method, and the effects of particle size on photocatalytic activity and magnetic property of BiFeO{sub 3} were investigated. The optical absorption spectra indicate that the band-gap energy increases with decreasing crystalline size due to the quantum-size effect. The enhancement of room-temperature weak ferromagnetism can be observed in nanoscale BiFeO{sub 3} particles, which should be attributed to the size-confinement effect on the magnetic ordering. In addition, BiFeO{sub 3} nanoparticles with diameter about 5 nm show good photocatalytic performance by photodegradation of Congo red under visible-light ({lambda}>400 nm) irradiation.

  14. Itinerant effects and enhanced magnetic interactions in Bi-based multilayer cuprates

    SciTech Connect (OSTI)

    Dean, M. P. M.; James, A. J. A.; Walters, A. C.; Bisogni, V.; Jarrige, I.; Hücker, M.; Giannini, E.; Fujita, M.; Pelliciari, J.; Huang, Y. B.; Konik, R. M.; Schmitt, T.; Hill, J. P.

    2014-12-04

    The cuprate high temperature superconductors exhibit a pronounced trend in which the superconducting transition temperature, T c, increases with the number of CuO₂ planes, n, in the crystal structure. We compare the magnetic excitation spectrum of Bi₂₊xSr₂₋xCuO₆+δ (Bi-2201) and Bi₂Sr₂Ca₂Cu₃O₁₀₊δ (Bi-2223), with n = 1 and n = 3 respectively, using Cu L₃-edge resonant inelastic x-ray scattering (RIXS). Near the anti-nodal zone boundary we find the paramagnon energy in Bi-2223 is substantially higher than that in Bi-2201, indicating that multilayer cuprates host stronger effective magnetic exchange interactions, providing a possible explanation for the Tc vs. n scaling. In contrast, the nodal direction exhibits very strongly damped, almost non-dispersive excitations. As a result, we argue that this implies that the magnetism in the doped cuprates is partially itinerant in nature.

  15. Feasible voltage-tap based quench detection in a Ag/Bi-2212 coil...

    Office of Scientific and Technical Information (OSTI)

    Small insert solenoids have been built using a commercial AgBi-2212 multifilamentary round wire, insulated with a new thin TiO2 - polymer coating insulation (thickness in 20 m ...

  16. BI/iPortal Training Opportunities in 2016 | Department of Energy

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

    Lunch and Learn: Tips and Tricks when using the BI Dashboards 12:00 pm - 1:00 pm WebEx All courses are in Eastern Standard Time (EST) For course descriptions, click here Thank ...

  17. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

    SciTech Connect (OSTI)

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particular that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.

  18. Theoretical study on the role of dynamics on the unusual magnetic properties in MnBi

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

    Shanavas, K. V.; Parker, David; Singh, David J.

    2014-11-27

    Here we study the electronic structure and lattice dynamics in the ferromagnet MnBi using first-principles calculations and a tight-binding model. The band structure around the Fermi level is dominated by Bi-p states which are the primary contributors to the magnetic anisotropy energy in the low temperature structure. A tight-binding model consisting of Mn-d and Bi-p states is developed and the parameters are determined from first-principles calculations. Phonon dispersions and elastic moduli exhibit several interesting features. In conclusion, the results imply that the magnetic interaction with the crystal lattice in MnBi is considerably more complex than previously thought and in particularmore » that there is a rich interplay between phonons and magnetism involving both magnetoelastic and magnetostrictive coupling.« less

  19. Thermodynamic and nonstoichiometric behavior of the lead-doped and lead-free Bi-2212 systems

    SciTech Connect (OSTI)

    Tetenbaum, M.; Hash, M.; Tani, B.S.; Luo, J.S.; Maroni, V.A.

    1997-02-01

    EMF measurements of oxygen fugacities as a function of stoichiometry were made on pb-doped and Pb-free superconducting ceramics at 700-815 C using oxygen titration. Equations of oxygen partial pressure vs composition and temperature were derived from the EMF measurements. Thermodynamic assessments of the partial molar quantities {Delta}{bar H}(O{sub 2}) and {Delta}{bar S}(O{sub 2}) for Pb-doped Bi- 2212 and Pb-free Bi-2212 indicate that the solid-state decomposition of these Bi cuprates at low oxygen partial pressure can be represented by the diphasic CuO-Cu{sub 2}O system. Comparison of these results with Pb-doped Bi-2223 in powder and silver sheath form is presented.

  20. CdSe/ZnSe quantum dot structures grown by molecular beam epitaxy with a CdTe submonolayer stressor

    SciTech Connect (OSTI)

    Sedova, I. V. Lyublinskaya, O. G.; Sorokin, S. V.; Sitnikova, A. A.; Toropov, A. A.; Donatini, F.; Dang, Si Le; Ivanov, S. V.

    2007-11-15

    A procedure for formation of CdSe quantum dots (QDs) in a ZnSe matrix is suggested. The procedure is based on the introduction of a CdTe submonolayer stressor deposited on the matrix surface just before deposition of the material of the QDs. (For CdTe/ZnSe structure, the relative lattice mismatch is {delta}a/a {approx} 14%.) The stressor forms small strained islands at the ZnSe surface, thus producing local fields of high elastic stresses controlling the process of the self-assembling of the QDs. According to the data of transmission electron microscopy, this procedure allows a considerable increase in the surface density of QDs, with a certain decrease in their lateral dimensions (down to 4.5 {+-} 1.5 nm). In the photoluminescence spectra, a noticeable ({approx}150 meV) shift of the peak to longer wavelengths from the position of the reference CdSe/ZnSe QD structure is observed. The shift is due to some transformation of the morphology of the QDs and an increase in the Cd content in the QDs. Comprehensive studies of the nanostructures by recording and analyzing the excitation spectra of photoluminescence, the time-resolved photoluminescence spectra, and the cathodoluminescence spectra show that the emission spectra involve two types of optical transitions, namely, the type-I transitions in the CdSeTe/ZnSe QDs and the type-II transitions caused mainly by the low cadmium content (Zn,Cd)(Se,Te)/ZnSe layer formed between the QDs.

  1. Compact Electrochemical Bi-functional NOx/O2 Sensors with an Internal

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

    Reference for High Temperature Applications | Department of Energy Electrochemical Bi-functional NOx/O2 Sensors with an Internal Reference for High Temperature Applications Compact Electrochemical Bi-functional NOx/O2 Sensors with an Internal Reference for High Temperature Applications A inexpensive compact O2 sensor has been developed using internal reference gas that is stable for months, has no complex electronics, and is amenable to mass production deer09_singh.pdf (756.14 KB) More

  2. New York Event to Show Bi-Partisan, International Support for Geothermal

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

    Energy in America | Department of Energy New York Event to Show Bi-Partisan, International Support for Geothermal Energy in America New York Event to Show Bi-Partisan, International Support for Geothermal Energy in America June 29, 2008 - 4:15pm Addthis NEW YORK, -- Demonstrating the widespread support for renewable, geothermal energy, the President of Iceland as well as officials of the current Bush and former Clinton Administrations are scheduled to speak at a workshop in New York City,

  3. Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca

    Office of Scientific and Technical Information (OSTI)

    (2) Cu (3) O (10+delta) Cuprate Superconductor (Journal Article) | SciTech Connect Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor Citation Details In-Document Search Title: Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor Authors: Ideta, S ; Takashima, K. ; Hashimoto, M. ; Yoshida, T. ; Fujimori, A. ; Anzai, H. ; Fujita, T. ; Nakashima, Y. ;

  4. Determination of the branching ratio for the {sup 209}Bi (n, {gamma}) {sup 210}Bi reaction from 500 eV to 20 keV

    SciTech Connect (OSTI)

    Borella, A.; Berthomieux, E.; Domingo-Pardo, C.; Gunsing, F.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P. M.; Milazzo, P. M.; Schillebeeckx, P.; Tagliente, G.; Tain, J.; Terlizzi, R.; Wynants, R.

    2006-07-01

    Energy differential neutron capture cross section measurements have been performed to determine the branching ratio for the {sup 209}Bi(n, {gamma}) reaction. The measurements were carried out at the time-of-flight facility GELINA of the IRMM in Geel (Belgium). The capture measurements were performed at a 12 m flight path using three High-Purity Germanium detectors. The experimental set-up was optimized to reduce the prompt background due to scattered neutrons. Several {gamma}-ray spectra corresponding to the {sup 209}Bi + n resonances up to 20 keV were deduced. The results of a preliminary data analysis are given in this paper. (authors)

  5. Victory: Order (2015-SE-42033) | Department of Energy

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

    Order (2015-SE-42033) Victory: Order (2015-SE-42033) October 27, 2015 DOE ordered Victory Refrigeration to pay a $1,600 civil penalty after finding Victory had manufactured and distributed in commerce in the U.S. at least 8 units of commercial refrigerator-freezer basic model RFS-1D-S1-EW-PT-HD, a noncompliant product. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Victory. Victory: Order (2015-SE-42033) (21.59 KB) More Documents & Publications

  6. 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.

  7. Bu Sung: Order (2015-SE-42007) | Department of Energy

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

    Order (2015-SE-42007) Bu Sung: Order (2015-SE-42007) October 13, 2015 DOE ordered Bu Sung America Corporation to pay a $71,480 civil penalty after finding Bu Sung had manufactured and distributed in commerce in the U.S. at least 361 units of basic model ESRF2, a noncompliant commercial refrigerator-freezer. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Bu Sung. Bu Sung: Order (2015-SE-42007) (123.64 KB) More Documents & Publications Bu Sung:

  8. AHT: Order (2015-SE-42031) | Department of Energy

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

    Order (2015-SE-42031) AHT: Order (2015-SE-42031) March 9, 2016 DOE ordered AHT Cooling Systems, Inc. to pay a $179,040 civil penalty after finding AHT had manufactured and distributed in commerce in the U.S. at least 1,032 units of commercial refrigeration equipment model RIO S 68 L F, a noncompliant product. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and AHT. AHT: Order (2015-SE-42031) (66.05 KB) More Documents & Publications AHT: Proposed Penalty

  9. BiGG Models: A platform for integrating, standardizing and sharing genome-scale models

    SciTech Connect (OSTI)

    King, Zachary A.; Lu, Justin; Drager, Andreas; Miller, Philip; Federowicz, Stephen; Lerman, Joshua A.; Ebrahim, Ali; Palsson, Bernhard O.; Lewis, Nathan E.

    2015-10-17

    In this study, genome-scale metabolic models are mathematically structured knowledge bases that can be used to predict metabolic pathway usage and growth phenotypes. Furthermore, they can generate and test hypotheses when integrated with experimental data. To maximize the value of these models, centralized repositories of high-quality models must be established, models must adhere to established standards and model components must be linked to relevant databases. Tools for model visualization further enhance their utility. To meet these needs, we present BiGG Models (http://bigg.ucsd.edu), a completely redesigned Biochemical, Genetic and Genomic knowledge base. BiGG Models contains more than 75 high-quality, manually-curated genome-scale metabolic models. On the website, users can browse, search and visualize models. BiGG Models connects genome-scale models to genome annotations and external databases. Reaction and metabolite identifiers have been standardized across models to conform to community standards and enable rapid comparison across models. Furthermore, BiGG Models provides a comprehensive application programming interface for accessing BiGG Models with modeling and analysis tools. As a resource for highly curated, standardized and accessible models of metabolism, BiGG Models will facilitate diverse systems biology studies and support knowledge-based analysis of diverse experimental data.

  10. BiGG Models: A platform for integrating, standardizing and sharing genome-scale models

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

    King, Zachary A.; Lu, Justin; Drager, Andreas; Miller, Philip; Federowicz, Stephen; Lerman, Joshua A.; Ebrahim, Ali; Palsson, Bernhard O.; Lewis, Nathan E.

    2015-10-17

    In this study, genome-scale metabolic models are mathematically structured knowledge bases that can be used to predict metabolic pathway usage and growth phenotypes. Furthermore, they can generate and test hypotheses when integrated with experimental data. To maximize the value of these models, centralized repositories of high-quality models must be established, models must adhere to established standards and model components must be linked to relevant databases. Tools for model visualization further enhance their utility. To meet these needs, we present BiGG Models (http://bigg.ucsd.edu), a completely redesigned Biochemical, Genetic and Genomic knowledge base. BiGG Models contains more than 75 high-quality, manually-curated genome-scalemore » metabolic models. On the website, users can browse, search and visualize models. BiGG Models connects genome-scale models to genome annotations and external databases. Reaction and metabolite identifiers have been standardized across models to conform to community standards and enable rapid comparison across models. Furthermore, BiGG Models provides a comprehensive application programming interface for accessing BiGG Models with modeling and analysis tools. As a resource for highly curated, standardized and accessible models of metabolism, BiGG Models will facilitate diverse systems biology studies and support knowledge-based analysis of diverse experimental data.« less

  11. Optical Properties of CdSe Nanoparticle Assemblies

    SciTech Connect (OSTI)

    Huser, T; Gerion, D; Zaitseva, N; Krol, D M; Leon, F R

    2003-11-24

    We report on three-dimensional fluorescence imaging of micron-size faceted crystals precipitated from solutions of CdSe nanocrystals. Such crystals have previously been suggested to be superlattices of CdSe quantum dots [1,2]. Possible applications for these materials include their use in optical and optoelectronic devices. The micron-size crystals were grown by slow evaporation from toluene solutions of CdSe nanocrystals in the range of 3-6 nm, produced by traditional wet-chemistry techniques. By using a confocal microscope with laser illumination, three-dimensional raster-scanning and synchronized hyper-spectral detection, we have generated spatial profiles of the fluorescence emission intensity and spectrum. The fluorescence data of the micro-crystals were compared with spectra of individual nanocrystals obtained from the same solution. The results do not support the assertion that these microcrystals consist of CdSe superlattices.

  12. Synthesis and properties of new CdSe-AgI-As{sub 2}Se{sub 3} chalcogenide glasses

    SciTech Connect (OSTI)

    Kassem, M.; ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque ; Le Coq, D.; Fourmentin, M.; Hindle, F.; Bokova, M.; Cuisset, A.; Masselin, P.; Bychkov, E.; ULCO, LPCA, EAC CNRS 4493 F-59140 Dunkerque

    2011-02-15

    Research highlights: {yields} Determination of the glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system. {yields} Characterization of macroscopic properties of the new CdSe-AgI-As{sub 2}Se{sub 3} glasses. {yields} Far infrared transmission of chalcogenide glasses. {yields} Characterization of the total conductivity of CdSe-AgI-As{sub 2}Se{sub 3} glasses. -- Abstract: The glass-forming region in the pseudo-ternary CdSe-AgI-As{sub 2}Se{sub 3} system was determined. Measurements including differential scanning calorimetry (DSC), density, and X-ray diffraction were performed. The effect resulting from the addition of CdSe or AgI has been highlighted by examining three series of different base glasses. The characteristic temperatures of the glass samples, including glass transition (T{sub g}), crystallisation (T{sub x}), and melting (T{sub m}) temperatures are reported and used to calculate their {Delta}T = T{sub x} - T{sub g} and their Hruby, H{sub r} = (T{sub x} - T{sub g})/(T{sub m} - T{sub x}), criteria. Evolution of the total electrical conductivity {sigma} and the room temperature conductivity {sigma}{sub 298} was also studied. The terahertz transparency domain in the 50-600 cm{sup -1} region was pointed for different chalcogenide glasses (ChGs) and the potential of the THz spectroscopy was suggested to obtain structural information on ChGs.

  13. Utility: Noncompliance Determination (2016-SE-42003) | Department of Energy

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

    Noncompliance Determination (2016-SE-42003) Utility: Noncompliance Determination (2016-SE-42003) December 30, 2015 DOE issued a Notice of Noncompliance Determination to Utility Refrigerator finding that commercial refrigeration equipment basic model number PT-R-75-SS-3S-3S-N does not comport with the energy conservation standards. DOE determined the product was noncompliant based on DOE testing. Utility must immediately notify each person (or company) to whom Utility distributed the noncompliant

  14. Victory: Noncompliance Determination (2015-SE-42033) | Department of Energy

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

    Noncompliance Determination (2015-SE-42033) Victory: Noncompliance Determination (2015-SE-42033) August 18, 2015 DOE issued a Notice of Noncompliance Determination to Victory Refrigeration finding that commercial refrigeration equipment basic model number RFS-1D-S1-EW-PT-HD (including each individual model within the basic model) does not comport with the energy conservation standards. DOE determined the product was noncompliant based on DOE testing. Victory must immediately notify each person

  15. Victory: Proposed Penalty (2015-SE-42033) | Department of Energy

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

    Proposed Penalty (2015-SE-42033) Victory: Proposed Penalty (2015-SE-42033) September 25, 2015 DOE alleged in a Notice of Proposed Civil Penalty that Victory Refrigeration manufactured and distributed noncompliant commercial refrigerator-freezer model RFS-1D-S1-EW-PT-HD in the U.S. Federal law subjects manufacturers and private labelers to civil penalties if those parties distribute in the U.S. products that do not meet applicable energy conservation standards. This civil penalty notice advises

  16. True: Order (2015-SE-42049) | Department of Energy

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

    True: Order (2015-SE-42049) True: Order (2015-SE-42049) February 4, 2016 DOE ordered True Manufacturing Co., Inc., to pay a $36,400 civil penalty after finding True had manufactured and distributed in commerce in the U.S. 182 units of True commercial refrigerator basic models TCGG-72 and TCGG-72-S, which did not meet the application energy conservation standard. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and True. Federal law subjects manufacturers and

  17. Haier: Compromise Agreement (2011-SE-1428) | Department of Energy

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

    Compromise Agreement (2011-SE-1428) Haier: Compromise Agreement (2011-SE-1428) April 23, 2013 DOE and Haier America Trading, LLC entered into a Compromise Agreement to resolve a case involving the distribution in commerce of residential freezers that did not meet the applicable energy conservation performance standard. Haier agreed to ensure that no additional units of the noncompliant freezers will be distributed in commerce in the U.S. and not to use the same model numbers in the future.

  18. Bu Sung: Proposed Penalty (2015-SE-42007) | Department of Energy

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

    Proposed Penalty (2015-SE-42007) Bu Sung: Proposed Penalty (2015-SE-42007) September 29, 2015 DOE alleged in a Notice of Proposed Civil Penalty that Bu Sung America Corporation d/b/a Everest Refrigeration manufactured and distributed noncompliant commercial refrigerator-freezers in the U.S. Federal law subjects manufacturers and private labelers to civil penalties if those parties distribute in the U.S. products that do not meet applicable energy conservation standards. This civil penalty notice

  19. First-principles studies on molecular beam epitaxy growth of GaAs1-xBix

    SciTech Connect (OSTI)

    Luo, Guangfu; Yang, Shujiang; Li, Jincheng; Arjmand, Mehrdad; Szlufarska, Izabela; Brown, April S.; Kuech, Thomas F.; Morgan, Dane

    2015-07-14

    We investigate the molecular beam epitaxy (MBE) growth of GaAs1-xBix film using density functional theory with spin-orbit coupling to understand the growth of this film, especially the mechanisms of Bi incorporation. We study the stable adsorption structures and kinetics of the incident molecules (As? molecule, Ga atom, Bi atom, and Bi? molecule) on the (2 x 1)-Gasub||Bi surface and a proposed q(1 x 1)-Gasub||AsAs surface has a quasi-(1 x 1) As layer above the Ga-terminated GaAs substrate and a randomly oriented As dimer layer on top. We obtain the desorption and diffusion barriers of the adsorbed molecules and also the reaction barriers of three key processes related to Bi evolution, namely, Bi incorporation, As/Bi exchange, and Bi clustering. The results help explain the experimentally observed dependence of Bi incorporation on the As/Ga ratio and growth temperature. Furthermore, we find that As? exchange with Bi of the (2 x 1)-Gasub||Bi surface is a key step controlling the kinetics of the Bi incorporation. Finally, we explore two possible methods to enhance the Bi incorporation, namely, replacing the MBE growth mode from codeposition of all fluxes with a sequential deposition of fluxes and applying asymmetric in-plane strain to the substrate.

  20. The influence of interfaces on properties of thin-film inorganic structural isomers containing SnSeNbSe? Subunits

    SciTech Connect (OSTI)

    Alemayehu, Matti B.; Falmbigl, Matthias; Ta, Kim; Johnson, David C.

    2015-08-28

    Inorganic isomers ([SnSe]1+?)m(NbSe?)n([SnSe]1+?)p(NbSe?)q([SnSe]1+?)r(NbSe?)s where m, n, p, q, r, and s are integers and m + p + r = n + q + s = 4 were prepared using the modulated elemental reactant technique. This series of all six possible isomers provides an opportunity to study the influence of interface density on properties while maintaining the same unit cell size and composition. As expected, all six compounds were observed to have the same atomic compositions and an almost c-axis lattice parameter of ?4.90 (5) nm, with a slight trend in the c-axis lattice parameter correlated with the different number of interfaces in the isomers: two, four and six. The structures of the constituents in the ab-plane were independent of one another, confirming the nonepitaxial relationship between them. The temperature dependent electrical resistivities revealed metallic behavior for all the six compounds. Surprisingly, the electrical resistivity at room temperature decreases with increasing number of interfaces. Hall measurements suggest this results from changes in carrier concentration, which increases with increasing thickness of the thickest SnSe block in the isomer. Carrier mobility scales with the thickness of the thickest NbSe? block due to increased interfacial scattering as the NbSe? blocks become thinner. The observed behavior suggests that the two constituents serve different purposes with respect to electrical transport. SnSe acts as a charge donor and NbSe? acts as the charge transport layer. This separation of function suggests that such heterostructures can be designed to optimize performance through choice of constituent, layer thickness, and layer sequence. A simplistic model, which predicts the properties of the complex isomers from a weighted sum of the properties of

  1. Vibrational properties of epitaxial Bi{sub 4}Te{sub 3} films as studied by Raman spectroscopy

    SciTech Connect (OSTI)

    Xu, Hao; Pan, Wenwu; Chen, Qimiao; Wu, Xiaoyan; Song, Yuxin E-mail: shumin@chalmers.se; Gong, Qian; Lu, Pengfei; Wang, Shumin E-mail: shumin@chalmers.se

    2015-08-15

    Bi{sub 4}Te{sub 3}, as one of the phases of the binary Bi–Te system, shares many similarities with Bi{sub 2}Te{sub 3}, which is known as a topological insulator and thermoelectric material. We report the micro-Raman spectroscopy study of 50 nm Bi{sub 4}Te{sub 3} films on Si substrates prepared by molecular beam epitaxy. Raman spectra of Bi{sub 4}Te{sub 3} films completely resolve the six predicted Raman-active phonon modes for the first time. Structural features and Raman tensors of Bi{sub 4}Te{sub 3} films are introduced. According to the wavenumbers and assignments of the six eigenpeaks in the Raman spectra of Bi{sub 4}Te{sub 3} films, it is found that the Raman-active phonon oscillations in Bi{sub 4}Te{sub 3} films exhibit the vibrational properties of those in both Bi and Bi{sub 2}Te{sub 3} films.

  2. Heterojunctions of model CdTe/CdSe mixtures

    SciTech Connect (OSTI)

    van Swol, Frank; Zhou, Xiaowang W.; Challa, Sivakumar R.; Martin, James E.

    2015-03-18

    We report on the strain behavior of compound mixtures of model group IIVI semiconductors. We use the StillingerWeber Hamiltonian that we recently introduced, specifically developed to model binary mixtures of group IIVI compounds such as CdTe and CdSe. We also employ molecular dynamics simulations to examine the behavior of thin sheets of material, bilayers of CdTe and CdSe. The lattice mismatch between the two compounds leads to a strong bending of the entire sheet, with about a 0.5 to 1 deflection between neighboring planes. To further analyze bilayer bending, we introduce a simple one-dimensional model and use energy minimization to find the angle of deflection. The analysis is equivalent to a least-squares straight line fit. We consider the effects of bilayers which are asymmetric with respect to the thickness of the CdTe and CdSe parts. We thus learn that the bending can be subdivided into four kinds depending on the compressive/tensile nature of each outer plane of the sheet. We use this approach to directly compare our findings with experimental results on the bending of CdTe/CdSe rods. To reduce the effects of the lattice mismatch we explore diffuse interfaces, where we mix (i.e. alloy) Te and Se, and estimate the strain response.

  3. Heterojunctions of model CdTe/CdSe mixtures

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

    van Swol, Frank; Zhou, Xiaowang W.; Challa, Sivakumar R.; Martin, James E.

    2015-03-18

    We report on the strain behavior of compound mixtures of model group II-VI semiconductors. We use the Stillinger-Weber Hamiltonian that we recently introduced, specifically developed to model binary mixtures of group II-VI compounds such as CdTe and CdSe. We also employ molecular dynamics simulations to examine the behavior of thin sheets of material, bilayers of CdTe and CdSe. The lattice mismatch between the two compounds leads to a strong bending of the entire sheet, with about a 0.5 to 1° deflection between neighboring planes. To further analyze bilayer bending, we introduce a simple one-dimensional model and use energy minimization tomore » find the angle of deflection. The analysis is equivalent to a least-squares straight line fit. We consider the effects of bilayers which are asymmetric with respect to the thickness of the CdTe and CdSe parts. We thus learn that the bending can be subdivided into four kinds depending on the compressive/tensile nature of each outer plane of the sheet. We use this approach to directly compare our findings with experimental results on the bending of CdTe/CdSe rods. To reduce the effects of the lattice mismatch we explore diffuse interfaces, where we mix (i.e. alloy) Te and Se, and estimate the strain response.« less

  4. Heterojunctions of model CdTe/CdSe mixtures

    SciTech Connect (OSTI)

    van Swol, Frank; Zhou, Xiaowang W.; Challa, Sivakumar R.; Martin, James E.

    2015-03-18

    We report on the strain behavior of compound mixtures of model group II-VI semiconductors. We use the Stillinger-Weber Hamiltonian that we recently introduced, specifically developed to model binary mixtures of group II-VI compounds such as CdTe and CdSe. We also employ molecular dynamics simulations to examine the behavior of thin sheets of material, bilayers of CdTe and CdSe. The lattice mismatch between the two compounds leads to a strong bending of the entire sheet, with about a 0.5 to 1° deflection between neighboring planes. To further analyze bilayer bending, we introduce a simple one-dimensional model and use energy minimization to find the angle of deflection. The analysis is equivalent to a least-squares straight line fit. We consider the effects of bilayers which are asymmetric with respect to the thickness of the CdTe and CdSe parts. We thus learn that the bending can be subdivided into four kinds depending on the compressive/tensile nature of each outer plane of the sheet. We use this approach to directly compare our findings with experimental results on the bending of CdTe/CdSe rods. To reduce the effects of the lattice mismatch we explore diffuse interfaces, where we mix (i.e. alloy) Te and Se, and estimate the strain response.

  5. EMPaSE: an Extensible Multi-Paradigm Simulation Environment

    Energy Science and Technology Software Center (OSTI)

    2010-08-05

    EMPaSE is a hierarchical, extensible, modular modeling environment for developing and running hybrid simulations of sequential-modular, systems dynamics, discrete-event, and agent-based paradigms. It contains two principle components: a multi-paradigm simulation engine and a graphical user interface. EMPaSE models are defined through a hierarchically-defined set of computational modules that define the simulation logic. Inter-module communication occurs through two complimentary systems: pull-based "ports" for general computation patterns and push-based "plugs" for event processing. Entities (i.e. agents) withinmore » the simulation operate within an abstract multi-network environment. The EMPaSE simulation engine is designed around a flexible plug-in architecture, allowing simulations to import computational modules, engine customizations, and interfaces to external applications from independent plug-in libraries. The EMPaSE GUI environment provides an environment for graphically constructing, executing, and debugging EMPaSE models. As with the simulation engine, the GUI is constructed on top of an extensible architecture that supports rapid customization of the user experience through external plug-in libraries.« less

  6. Reverse Monte Carlo simulation of Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} glasses

    SciTech Connect (OSTI)

    Abdel-Baset, A. M.; Rashad, M.; Moharram, A. H.

    2013-12-16

    Two-dimensional Monte Carlo of the total pair distribution functions g(r) is determined for Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} alloys, and then it used to assemble the three-dimensional atomic configurations using the reverse Monte Carlo simulation. The partial pair distribution functions g{sub ij}(r) indicate that the basic structure unit in the Se{sub 80}Te{sub 15}Sb{sub 5} glass is di-antimony tri-selenide units connected together through Se-Se and Se-Te chain. The structure of Se{sub 80}Te{sub 20} alloys is a chain of Se-Te and Se-Se in addition to some rings of Se atoms.

  7. Synthesis and characterization of BiFeO{sub 3} for photocatalytic degradation of azo dye

    SciTech Connect (OSTI)

    Kaur, Manpreet Uniyal, Poonam

    2015-08-28

    A novel approach is reported to synthesize single phase BiFeO{sub 3} via. sol-gel auto combustion method using glycine as fuel. Synthesized powder was subjected to annealing at different temperatures, i.e. 400 °C, 450 °C, 500 °C, 550 °C, and 600°C. Crystal structure of BiFeO{sub 3} samples examined by X-ray diffraction indicates that the samples were single-phased with different particle sizes, as particle sizes are temperature dependent and crystallized in rhombohedral structure. As the temperature was increased, the diffraction peak intensity of BiFeO3 in the XRD spectra gradually enhanced and the diffraction peaks became sharper. The optical properties of the resultant BiFeO{sub 3} were characterized using UV-Vis spectrophotometer over the range of 350-800 nm. UV-vis spectra of all the samples indicate that optical band gap lies in the visible region in the range of 2.2-2.07 eV at all temperatures. Moreover, photocatalytic properties of the BiFeO{sub 3} powders were investigated by the photodegradation of Reactive Black-5 (RB-5)

  8. Highly Reversible Mg Insertion in Nanostructured Bi for Mg Ion Batteries

    SciTech Connect (OSTI)

    Shao, Yuyan; Gu, Meng; Li, Xiaolin; Nie, Zimin; Zuo, Pengjian; Li, Guosheng; Liu, Tianbiao L.; Xiao, Jie; Cheng, Yingwen; Wang, Chong M.; Zhang, Jiguang; Liu, Jun

    2014-01-08

    Rechargeable magnesium batteries have attracted wide attention for energy storage. Currently, most studies focus on Mg metal as the anode, but this approach is still limited by the properties of the electrolyte and poor control of the Mg plating/stripping processes.1,2 Here we report the synthesis and application of Bi nanotubes as a high performance anode material for rechargeable Mg ion batteries. The nanostructured Bi anode delivers a high reversible specific capacity (350 mAh/gBi, or 3430 mAh/cm3 Bi), excellent stability, and high columbic efficiency (95 % initial and very close to 100% afterwards). The good performance is attributed to the unique properties of in-situ formed, interconnected nanoporous bismuth. Such nanostructures can effectively accommodate the large volume change without losing electric contact and significantly reduce diffusion length for Mg2+. Significantly, the nanostructured Bi anode can be used with conventional electrolytes which will open new opportunities to study Mg ion battery chemistry and further improve the properties. The performance and the stability of a full cell Mg ion battery have been demonstrated with conventional electrolytes. This work suggests that other high energy density alloy compounds may also be considered for Mg-ion chemistry for high capacity electrode materials.

  9. Human papillomavirus 16 E5 induces bi-nucleated cell formation by cell-cell fusion

    SciTech Connect (OSTI)

    Hu Lulin; Plafker, Kendra; Vorozhko, Valeriya; Zuna, Rosemary E.; Hanigan, Marie H.; Gorbsky, Gary J.; Plafker, Scott M.; Angeletti, Peter C.; Ceresa, Brian P.

    2009-02-05

    Human papillomaviruses (HPV) 16 is a DNA virus encoding three oncogenes - E5, E6, and E7. The E6 and E7 proteins have well-established roles as inhibitors of tumor suppression, but the contribution of E5 to malignant transformation is controversial. Using spontaneously immortalized human keratinocytes (HaCaT cells), we demonstrate that expression of HPV16 E5 is necessary and sufficient for the formation of bi-nucleated cells, a common characteristic of precancerous cervical lesions. Expression of E5 from non-carcinogenic HPV6b does not produce bi-nucleate cells. Video microscopy and biochemical analyses reveal that bi-nucleates arise through cell-cell fusion. Although most E5-induced bi-nucleates fail to propagate, co-expression of HPV16 E6/E7 enhances the proliferation of these cells. Expression of HPV16 E6/E7 also increases bi-nucleated cell colony formation. These findings identify a new role for HPV16 E5 and support a model in which complementary roles of the HPV16 oncogenes lead to the induction of carcinogenesis.

  10. Photoconductive properties of Bi{sub 2}S{sub 3} nanowires

    SciTech Connect (OSTI)

    Andzane, J. Kunakova, G.; Erts, D.; Varghese, J.; Holmes, J. D.

    2015-02-14

    The photoconductive properties of Bi{sub 2}S{sub 3} nanowires synthesized inside anodized alumina (AAO) membrane have been characterized as a function of illuminating photon energy between the wavelengths of 500 to 900 nm and at constant illumination intensity of 1–4 μW·cm{sup −2}. Photoconductivity spectra, photocurrent values, photocurrent onset/decay times of individual Bi{sub 2}S{sub 3} nanowires liberated from the AAO membrane were determined and compared with those of arrays of as-produced Bi{sub 2}S{sub 3} nanowires templated inside pores of AAO membrane. The alumina membrane was found to significantly influence the photoconductive properties of the AAO-hosted Bi{sub 2}S{sub 3} nanowires, when compared to liberated from the AAO membrane individual Bi{sub 2}S{sub 3} nanowires, possibly due to charge carrier trapping at the interface between the nanowire surface and the pore walls.

  11. The Usefulness of Bi-Level Switching; Original Technical Note: November 1998. Revised August, 1999

    SciTech Connect (OSTI)

    Building Technologies Department

    1998-11-01

    California's Title 24 Energy Efficiency Building Standard requires multiple lighting level control in all individual offices. Usually, this requirement is fulfilled using bi-level switching. With bi-level switching, each office occupant is provided with two wall switches near the doorway to control their lights. In a typical installation, one switch would control 1/3 of the fluorescent lamps in the ceiling lighting system, while the other switch would control the remaining 2/3 of the lamps. This allows four possible light levels: OFF, 1/3, 2/3 and FULL lighting. Because it has been required by building code since 1983, bi-level switching is common in California office buildings. However, there is no published evidence showing that occupants sometimes use just one switch rather than just switching on both switches when entering the room. Consequently, some have questioned whether bi-level switching is a necessary or desirable requirement for typical office buildings. In fact, the draft national standard, ASHRAE Standard 90.1-1989K apparently does not require bi-level switching at all.

  12. Electrochemical solar cells using CdSe thin film electrodes

    SciTech Connect (OSTI)

    Xiao, Xu-Rui; Tien, H.Ti.

    1983-01-01

    Electrochemical photocells consisting of a CdSe thin film anode and a Pt cathode immersed in 1M Na/sub 2/S-NaOH-S solution have been studied. CdSe thin films were formed on Ti, Cr, Mo, SnO/sub 2/, glassy carbon, and graphite substrates by coating an aqueous mixture of CdSe, ZnCl/sub 2/, and surfactant, subsequently sintering at 400/sup 0/-500/sup 0/C in air. The current-voltage (I-V) relations, output power efficiency, open-circuit voltage, and short-circuit current were measured. Seven percent power conversion efficiency was obtained at 20 mW/cm/sup 2/ light intensity after photoetching. The monochromatic I-V curves were analyzed.

  13. Utility: Order (2016-SE-42003) | Department of Energy

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

    SE-42003) Utility: Order (2016-SE-42003) March 1, 2016 DOE ordered Utility Refrigerator to pay a $200 civil penalty after finding Utility manufactured and distributed in commerce in the U.S. 1 unit of a Utility brand commercial refrigerator, model PT-R-75-SS-3S-3S-N. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Utility. Federal law subjects manufacturers and private labelers to civil penalties if those parties distribute in the U.S. products that do

  14. Friedrich: Order (2014-SE-15010) | Department of Energy

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

    Order (2014-SE-15010) Friedrich: Order (2014-SE-15010) October 27, 2015 DOE ordered Friedrich Air Conditioning Co. to pay a civil penalty of $1,494,626.25 after finding Friedrich had manufactured and distributed in commerce in the U.S. 8,241 units of Friedrich model SQ10N10, a noncompliant room air conditioner. The Order adopted a Compromise Agreement, which reflected settlement terms between DOE and Friedrich. Federal law subjects manufacturers and private labelers to civil penalties if those

  15. Excited-State Relaxation in PbSe Quantum Dots

    SciTech Connect (OSTI)

    An, J. M.; Califano, M.; Franceschetti, A.; Zunger, A.

    2008-01-01

    In solids the phonon-assisted, nonradiative decay from high-energy electronic excited states to low-energy electronic excited states is picosecond fast. It was hoped that electron and hole relaxation could be slowed down in quantum dots, due to the unavailability of phonons energy matched to the large energy-level spacings ('phonon-bottleneck'). However, excited-state relaxation was observed to be rather fast ({le}1 ps) in InP, CdSe, and ZnO dots, and explained by an efficient Auger mechanism, whereby the excess energy of electrons is nonradiatively transferred to holes, which can then rapidly decay by phonon emission, by virtue of the densely spaced valence-band levels. The recent emergence of PbSe as a novel quantum-dot material has rekindled the hope for a slow down of excited-state relaxation because hole relaxation was deemed to be ineffective on account of the widely spaced hole levels. The assumption of sparse hole energy levels in PbSe was based on an effective-mass argument based on the light effective mass of the hole. Surprisingly, fast intraband relaxation times of 1-7 ps were observed in PbSe quantum dots and have been considered contradictory with the Auger cooling mechanism because of the assumed sparsity of the hole energy levels. Our pseudopotential calculations, however, do not support the scenario of sparse hole levels in PbSe: Because of the existence of three valence-band maxima in the bulk PbSe band structure, hole energy levels are densely spaced, in contradiction with simple effective-mass models. The remaining question is whether the Auger decay channel is sufficiently fast to account for the fast intraband relaxation. Using the atomistic pseudopotential wave functions of Pb{sub 2046}Se{sub 2117} and Pb{sub 260}Se{sub 249} quantum dots, we explicitly calculated the electron-hole Coulomb integrals and the P {yields} S electron Auger relaxation rate. We find that the Auger mechanism can explain the experimentally observed P {yields} S

  16. Quaternary heterostructured Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} composite: Synthesis and enhanced visible-light-driven photocatalytic activity

    SciTech Connect (OSTI)

    Lin, Xue; Guo, Xiaoyu; Shi, Weilong; Zhai, Hongju; Yan, Yongsheng; Wang, Qingwei

    2015-09-15

    In this work, a novel quaternary heterostructured Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} composite was fabricated through a low-temperature solution-phase route. The XRD, SEM, EDX and XPS results indicated the as-prepared sample is a four-phase composite of Bi{sub 2}O{sub 2}CO{sub 3}, Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}, Bi{sub 2}MoO{sub 6}, and Ag. The photocatalytic activities of the as-synthesized samples were evaluated towards the degradation of phenol red aqueous solution. The results showed that the as-synthesized Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} photocatalysts displayed much higher photocatalytic activities in comparison with pure Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}, pure Bi{sub 2}MoO{sub 6}, and Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} composite. Among them, the 2.5% Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} sample performed the best. The enhanced photocatalytic activity of the composite photocatalyst was attributed predominantly to the efficient separation of photoinduced electrons and holes. In addition, Ag nanoparticles were photodeposited on the surface of the composite to increase visible-light absorption via the surface plasmon resonance, which is also beneficial to the enhancement of photocatalytic performance. The possible photocatalytic mechanism of the quaternary heterostructure was also discussed in detail. - Graphical abstract: Quaternary heterostructured Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} were fabricated. The as-synthesized Ag–Bi{sub 2}O{sub 2}CO{sub 3}/Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} photocatalysts displayed much higher photocatalytic activities in comparison with pure Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}, pure Bi{sub 2}MoO{sub 6}, and Bi{sub 3.64}Mo{sub 0.36}O{sub 6.55}/Bi{sub 2}MoO{sub 6} composite

  17. Controlled synthesis of T-shaped BiVO{sub 4} and enhanced visible light responsive photocatalytic activity

    SciTech Connect (OSTI)

    Dong, Shuying; Yu, Chongfei; Li, Yukun; Li, Yihui; Sun, Jianhui; Geng, Xiaofei

    2014-03-15

    A novel T-shaped BiVO{sub 4} microcrystal photocatalyst was successfully synthesized by the hydrothermal method with the aid of a structure-directing surfactant SDBS in the present study. Having received well characterization with the aid of various techniques and the results showed that the SDBS greatly changed the microstructure of BiVO{sub 4}, which had a unique T shape and belonged to the monoclinic family. The fast exchange dynamics between the surfactants bound to the Bi{sup 3+} seed surface and the free VO{sub 3}{sup ?} in the solution significantly increase the rate of heterogeneous nucleation. In addition, the photocatalytic activity of the prepared T-shaped BiVO{sub 4} was evaluated by the degradation of Methylene Blue solution under visible light irradiation, 17% and 47% higher decolorization rates than the commercial P25 and BiVO{sub 4} synthesized without SDBS, respectively. Meanwhile, it has been found that the degradation kinetics of MB fitted the pseudo-first-order kinetics and the T-shaped BiVO{sub 4} also displayed high photocatalytic performance for metronidazole degradation. -- Graphical abstract: H{sub 2}O{sub 2} molecules function as electron trapping reagent to react with e{sup ?} to enhance the photocatalytic degradation efficiency of MB in the BiVO{sub 4}/H{sub 2}O{sub 2} system under visible light irradiation. Highlights: T-shaped BiVO{sub 4} was synthesized using SDBS as a structure-directing surfactant. SDBS greatly changed the microstructure of BiVO{sub 4}. The T-shaped BiVO{sub 4} had a better visible-light photocatalytic activity. Degradation kinetics of MB by BiVO{sub 4} fitted the pseudo-first-order kinetics.

  18. Hydrogen in polar intermetallics: Syntheses and structures of the ternary Ca5Bi3D0.93, Yb5Bi3Hx, and Sm5Bi3H~1 by powder neutron or single crystal X-ray diffraction

    SciTech Connect (OSTI)

    Leon-Escamilla, E. Alejandro; Dervenagas, Panagiotis; Stasis, Constantine; Corbett, John D.

    2010-01-01

    The syntheses of the title compounds are described in detail. Structural characterizations from refinements of single crystal X-ray diffraction data for Yb{sub 5}Bi{sub 3}H{sub x} and Sm{sub 5}Bi{sub 3}H{sub 1} and of powder neutron diffraction data for Ca{sub 5}Bi{sub 3}D{sub 0.93(3)} are reported. These confirm that all three crystallize with the heavy atom structure type of {beta}-Yb{sub 5}Sb{sub 3}, and the third gives the first proof that the deuterium lies in the center of nominal calcium tetrahedra, isostructural with the Ca{sub 5}Sb{sub 3}F-type structure. These Ca and Yb phases are particularly stable with respect to dissociation to Mn{sub 5}Si{sub 3}-type product plus H{sub 2}. Some contradictions in the literature regarding Yb{sub 5}Sb{sub 3} and Yb{sub 5}Sb{sub 3}H{sub x} phases are considered in terms of adventitious hydrogen impurities that are generated during reactions in fused silica containers at elevated temperatures.

  19. Experimental Realization of a Three-Dimensional Topological Insulator, Bi 2Te3

    SciTech Connect (OSTI)

    Siemons, W.

    2010-02-24

    Three-dimensional topological insulators are a new state of quantum matter with a bulk gap and odd number of relativistic Dirac fermions on the surface. By investigating the surface state of Bi{sub 2}Te{sub 3} with angle-resolved photoemission spectroscopy, we demonstrate that the surface state consists of a single nondegenerate Dirac cone. Furthermore, with appropriate hole doping, the Fermi level can be tuned to intersect only the surface states, indicating a full energy gap for the bulk states. Our results establish that Bi{sub 2}Te{sub 3} is a simple model system for the three-dimensional topological insulator with a single Dirac cone on the surface. The large bulk gap of Bi{sub 2}Te{sub 3} also points to promising potential for high-temperature spintronics applications.

  20. Barrier-free subsurface incorporation of 3d metal atoms into Bi(111) films

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

    Klein, C.; Vollmers, N. J.; Gerstmann, U.; Zahl, P.; Lukermann, D.; Jnawali, G.; Pfnur, H.; Sutter, P.; Tegenkamp, C.; Schmidt, W. G.; et al

    2015-05-27

    By combining scanning tunneling microscopy with density functional theory it is shown that the Bi(111) surface provides a well-defined incorporation site in the first bilayer that traps highly coordinating atoms such as transition metals (TMs) or noble metals. All deposited atoms assume exactly the same specific sevenfold coordinated subsurface interstitial site while the surface topography remains nearly unchanged. Notably, 3d TMs show a barrier-free incorporation. The observed surface modification by barrier-free subsorption helps to suppress aggregation in clusters. Thus, it allows a tuning of the electronic properties not only for the pure Bi(111) surface, but may also be observed formore » topological insulators formed by substrate-stabilized Bi bilayers.« less

  1. Enhanced spin Hall effect by electron correlations in CuBi alloys

    SciTech Connect (OSTI)

    Gu, Bo Xu, Zhuo; Mori, Michiyasu; Maekawa, Sadamichi; Ziman, Timothy

    2015-05-07

    A recent experiment in CuBi alloys obtained a large spin Hall angle (SHA) of −0.24 (Niimi et al., Phys. Rev. Lett. 109, 156602 (2012)). We find that the SHA can be dramatically enhanced by Bi impurities close to the Cu surface. The mechanisms of this enhancement are two-fold. One is that the localized impurity state on surface has a decreased hybridization and combined with Coulomb correlation effect. The other comes from the low-dimensional state of conduction electrons on surface, which results in a further enhancement of skew scattering by impurities. Furthermore, we note that a discrepancy in sign of SHA between the experiment and previous theories is simply caused by different definitions of SHA. This re-establishes skew scattering as the essential mechanism underlying the spin Hall effect in CuBi alloys.

  2. Structural and dielectric properties of Nd/Ca co-doped bi-ferrite multiferroics

    SciTech Connect (OSTI)

    Kumar, Ashwini E-mail: ashu.dhanda@gmail.com; Sharma, Poorva E-mail: ashu.dhanda@gmail.com; Varshney, Dinesh E-mail: ashu.dhanda@gmail.com

    2014-04-24

    Single-phase polycrystalline samples of Bi{sub 0.8}Nd{sub 0.2−x}Ca{sub x}FeO{sub 3} (x = 0.0, 0.1) were synthesized by chemical coprecipitation method. X-ray diffraction patterns accompanied by Rietveld-refined crystal structure parameters reveal the phase transition of Bi{sub 0.8}Nd{sub 0.1}Ca{sub 0.1}FeO{sub 3} with rhombohedral R3c symmetry to triclinic structure of Bi{sub 0.8}Nd{sub 0.2}FeO{sub 3} sample. Frequency dependence of dielectric constant (ε') and dielectric loss (tanδ), infers enhancement of both ε' (tanδ) in narrow band gap of Nd/Ca co-doped BFO as compare to wide band pristine BFO.

  3. Orbitally-driven giant phonon anharmonicity in SnSe

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

    Li, Chen W.; Hong, Jiawang; May, Andrew F.; Bansal, Dipanshu; Chi, Songxue; Hong, Tao; Ehlers, Georg; Delaire, Olivier A.

    2015-10-19

    We understand that elementary excitations and their couplings in condensed matter systems is critical to develop better energy-conversion devices. In thermoelectric materials, the heat-to-electricity conversion efficiency is directly improved by suppressing the propagation of phonon quasiparticles responsible for macroscopic thermal transport. The material with the current record for thermoelectric conversion efficiency, SnSe, achieves an ultra-low thermal conductivity, but the mechanism enabling this strong phonon scattering remains largely unknown. Using inelastic neutron scattering measurements and first-principles simulations, we mapped the four-dimensional phonon dispersion surfaces of SnSe, and revealed the origin of ionic-potential anharmonicity responsible for the unique properties of SnSe. Wemore » show that the giant phonon scattering arises from an unstable electronic structure, with orbital interactions leading to a ferroelectric-like lattice instability. Our results provide a microscopic picture connecting electronic structure and phonon anharmonicity in SnSe, and offers precious insights on how electron-phonon and phononphonon interactions may lead to the realization of ultra-low thermal conductivity.« less

  4. Orbitally-driven giant phonon anharmonicity in SnSe

    SciTech Connect (OSTI)

    Li, Chen W.; Hong, Jiawang; May, Andrew F.; Bansal, Dipanshu; Chi, Songxue; Hong, Tao; Ehlers, Georg; Delaire, Olivier A.

    2015-10-19

    We understand that elementary excitations and their couplings in condensed matter systems is critical to develop better energy-conversion devices. In thermoelectric materials, the heat-to-electricity conversion efficiency is directly improved by suppressing the propagation of phonon quasiparticles responsible for macroscopic thermal transport. The material with the current record for thermoelectric conversion efficiency, SnSe, achieves an ultra-low thermal conductivity, but the mechanism enabling this strong phonon scattering remains largely unknown. Using inelastic neutron scattering measurements and first-principles simulations, we mapped the four-dimensional phonon dispersion surfaces of SnSe, and revealed the origin of ionic-potential anharmonicity responsible for the unique properties of SnSe. We show that the giant phonon scattering arises from an unstable electronic structure, with orbital interactions leading to a ferroelectric-like lattice instability. Our results provide a microscopic picture connecting electronic structure and phonon anharmonicity in SnSe, and offers precious insights on how electron-phonon and phononphonon interactions may lead to the realization of ultra-low thermal conductivity.

  5. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOE Patents [OSTI]

    Dorris, Stephen E.; Poeppel, Roger B.; Prorok, Barton C.; Lanagan, Michael T.; Maroni, Victor A.

    1994-01-01

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor.

  6. Synthesis of highly phase pure (Bi, Pb)-Sr-Ca-Cu-O superconductor

    DOE Patents [OSTI]

    Dorris, S.E.; Poeppel, R.B.; Prorok, B.C.; Lanagan, M.T.; Maroni, V.A.

    1994-10-11

    An article and method of manufacture of (Bi,Pb)-Sr-Ca-Cu-O superconductor are disclosed. The superconductor is manufactured by preparing a first powdered mixture of bismuth oxide, lead oxide, strontium carbonate, calcium carbonate and copper oxide. A second powdered mixture is then prepared of strontium carbonate, calcium carbonate and copper oxide. The mixtures are calcined separately with the two mixtures then combined. The resulting combined mixture is then subjected to a powder in tube deformation and thermal processing to produce a substantially phase pure (Bi,Pb)-Sr-Ca-Cu-O superconductor. 5 figs.

  7. Lattice accommodation of epitaxial Bi(111) films on Si(001) studied with SPA-LEED and AFM

    SciTech Connect (OSTI)

    Jnawali, G.; Hattab, H.; Krenzer, B.; Horn von Hoegen, M.

    2006-11-15

    The growth of Bi on a Si(001) surface is studied in situ by spot profile analyzing low-energy electron diffraction and ex situ by atomic force microscopy. A continuous epitaxial Bi(111) film with a thickness of 6 nm is grown at 150 K in a bilayer growth mode. During annealing to 450 K the lattice mismatch between Si(001) and Bi(111) is accommodated by a periodic interfacial misfit dislocation array. On this relaxed template, Bi(111) films can be grown to any desired thickness. Such films are composed of twinned and 90 deg. rotated micrometer sized Bi(111) crystallites with a roughness of less than 0.6 nm for a 30 nm thick film.

  8. Giant piezoelectricity of monolayer group IV monochalcogenides: SnSe, SnS, GeSe, and GeS

    SciTech Connect (OSTI)

    Fei, Ruixiang; Yang, Li; Li, Wenbin; Li, Ju

    2015-10-26

    We predict enormous, anisotropic piezoelectric effects in intrinsic monolayer group IV monochalcogenides (MX, M=Sn or Ge, X=Se or S), including SnSe, SnS, GeSe, and GeS. Using first-principle simulations based on the modern theory of polarization, we find that their piezoelectric coefficients are about one to two orders of magnitude larger than those of other 2D materials, such as MoS{sub 2} and GaSe, and bulk quartz and AlN which are widely used in industry. This enhancement is a result of the unique “puckered” C{sub 2v} symmetry and electronic structure of monolayer group IV monochalcogenides. Given the achieved experimental advances in the fabrication of monolayers, their flexible character, and ability to withstand enormous strain, these 2D structures with giant piezoelectric effects may be promising for a broad range of applications such as nano-sized sensors, piezotronics, and energy harvesting in portable electronic devices.

  9. Bandgap and optical absorption edge of GaAs{sub 1?x}Bi{sub x} alloys with 0?

    SciTech Connect (OSTI)

    Masnadi-Shirazi, M.; Lewis, R. B.; Bahrami-Yekta, V.; Tiedje, T.; Chicoine, M.; Servati, P.

    2014-12-14

    The compositional dependence of the fundamental bandgap of pseudomorphic GaAs{sub 1?x}Bi{sub x} layers on GaAs substrates is studied at room temperature by optical transmission and photoluminescence spectroscopies. All GaAs{sub 1?x}Bi{sub x} films (0???x???17.8%) show direct optical bandgaps, which decrease with increasing Bi content, closely following density functional theory predictions. The smallest measured bandgap is 0.52?eV (?2.4??m) at 17.8% Bi. Extrapolating a fit to the data, the GaAs{sub 1?x}Bi{sub x} bandgap is predicted to reach 0?eV at 35% Bi. Below the GaAs{sub 1?x}Bi{sub x} bandgap, exponential absorption band tails are observed with Urbach energies 36 times larger than that of bulk GaAs. The Urbach parameter increases with Bi content up to 5.5% Bi, and remains constant at higher concentrations. The lattice constant and Bi content of GaAs{sub 1?x}Bi{sub x} layers (0?Bi is estimated to be 6.33??0.05?, from extrapolation of the Rutherford backscattering spectrometry and x-ray diffraction data.

  10. Epitaxial growth of CZT(S,Se) on silicon

    DOE Patents [OSTI]

    Bojarczuk, Nestor A.; Gershon, Talia S.; Guha, Supratik; Shin, Byungha; Zhu, Yu

    2016-03-15

    Techniques for epitaxial growth of CZT(S,Se) materials on Si are provided. In one aspect, a method of forming an epitaxial kesterite material is provided which includes the steps of: selecting a Si substrate based on a crystallographic orientation of the Si substrate; forming an epitaxial oxide interlayer on the Si substrate to enhance wettability of the epitaxial kesterite material on the Si substrate, wherein the epitaxial oxide interlayer is formed from a material that is lattice-matched to Si; and forming the epitaxial kesterite material on a side of the epitaxial oxide interlayer opposite the Si substrate, wherein the epitaxial kesterite material includes Cu, Zn, Sn, and at least one of S and Se, and wherein a crystallographic orientation of the epitaxial kesterite material is based on the crystallographic orientation of the Si substrate. A method of forming an epitaxial kesterite-based photovoltaic device and an epitaxial kesterite-based device are also provided.

  11. American Ref-Fuel of SE CT Biomass Facility | Open Energy Information

    Open Energy Info (EERE)

    Ref-Fuel of SE CT Biomass Facility Jump to: navigation, search Name American Ref-Fuel of SE CT Biomass Facility Facility American Ref-Fuel of SE CT Sector Biomass Facility Type...

  12. SpacePak: Proposed Penalty (2014-SE-16012) | Department of Energy

    Office of Environmental Management (EM)

    SpacePak: Proposed Penalty (2014-SE-16012) (19.1 KB) More Documents & Publications SpacePak: Noncompliance Determination (2014-SE-16012) SpacePak: Order (2014-SE-16012) Crane: ...

  13. Deformation potentials of CdSe quantum dots

    SciTech Connect (OSTI)

    Li, Jingbo; Wang, Lin-Wang

    2004-06-02

    The size dependent deformation potentials of CdSe quantum dots are studied by first principle and semi-empirical pseudopotentials calculations. They find that the amplitude of the quantum dot deformation potential is only slightly larger than the bulk value, and this increase is mostly caused by the off {Lambda} point deformation potentials in the bulk, which are larger in amplitude than the {Lambda} point deformation potential.

  14. Major UMass User Facilities-Resources-PHaSe-EFRC

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

    Major UMass User Facilities TRPL photo Researchers can access the capabilities of the various investigator interested in organic electronic materials, in PHaSE's original participating departments, and other centers and facilities, including the following: Materials Research Science & Engineering Center Center for Hierarchal Manufacturing High Field NMR Facility Mass Spectrometry Facility EPR Facility Keck Nanostructures Laboratory X-ray powder and single crystal diffraction Polymer

  15. Islandaire: Noncompliance Determination (2015-SE-43007) | Department of

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

    Energy 7) Islandaire: Noncompliance Determination (2015-SE-43007) February 25, 2016 DOE issued a Notice of Noncompliance Determination to Islandaire, Inc. finding that the Islandaire package terminal air conditioner basic model CPZ-09ANR1-B, which includes models EZ4209B and EZDR09B, does not comport with the applicable energy conservation standards. DOE determined the product was noncompliant based on DOE testing. Islandaire must immediately notify each person (or company) to whom it

  16. Islandaire: Noncompliance Determination (2015-SE-43008) | Department of

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

    Energy 8) Islandaire: Noncompliance Determination (2015-SE-43008) February 25, 2016 DOE issued a Notice of Noncompliance Determination to Islandaire, Inc. finding that the Islandaire package terminal air conditioner basic model CPZ-129ANR1-B, which includes model EZDR12B, does not comport with the applicable energy conservation standards. DOE determined the product was noncompliant based on DOE testing. Islandaire must immediately notify each person (or company) to whom it distributed the

  17. Islandaire: Noncompliance Determination (2015-SE-43009) | Department of

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

    Energy 9) Islandaire: Noncompliance Determination (2015-SE-43009) February 25, 2016 DOE issued a Notice of Noncompliance Determination to Islandaire, Inc. finding that the Islandaire package terminal air conditioner basic model CPZ-07ANR1-B, which includes model EZDR07B, does not comport with the applicable energy conservation standards. DOE determined the product was noncompliant based on DOE testing. Islandaire must immediately notify each person (or company) to whom it distributed the

  18. Quantum confined acceptors and donors in InSe nanosheets

    SciTech Connect (OSTI)

    Mudd, G. W.; Patan, A. Makarovsky, O.; Eaves, L.; Kudrynskyi, Z. R.; Kovalyuk, Z. D.; Fay, M. W.; Zlyomi, V.; Falko, V.

    2014-12-01

    We report on the radiative recombination of photo-excited carriers bound at native donors and acceptors in exfoliated nanoflakes of nominally undoped rhombohedral ?-polytype InSe. The binding energies of these states are found to increase with the decrease in flake thickness, L. We model their dependence on L using a two-dimensional hydrogenic model for impurities and show that they are strongly sensitive to the position of the impurities within the nanolayer.

  19. Preparation of Bi-Sr-Ca-Cu-O superconductors from oxide-glass precursors

    DOE Patents [OSTI]

    Hinks, David G.; Capone, II, Donald W.

    1992-01-01

    A superconductor and precursor therefor from oxide mixtures of Ca, Sr, Bi and Cu. Glass precursors quenched to elevated temperatures result in glass free of crystalline precipitates having enhanced mechanical properties. Superconductors are formed from the glass precursors by heating in the presence of oxygen to a temperature below the melting point of the glass.

  20. Enhanced irreversibility by crystal defects in the Bi-Sr-Ca-Cu-O system

    SciTech Connect (OSTI)

    Salem-Sugui, S. Jr.; Shi, Donglu; McFarland, S.E.

    1991-04-01

    We measured magnetic irreversibility, H*(T), in liquid-quenched Bi-Sr-Ca-Cu-O samples with various microstructures at high applied field (up to 7 T). We found that H*(T) is considerably increased in the Bi{sub 2}Sr{sub 2}Ca{sub 3}Cu{sub 4}O{sub x} (2234) sample with a large amount of crystal defects, including severe lattice distortion and calcium and copper rich precipitates. We argue that the lattice distortion may affect the degree of anisotropy and the Josephson coupling between the Cu-O layers, which in turn enhance the irreversibility in the Bi-Sr-Ca-Cu-O system. A critical current density, J{sub c}, of 8 {times} 10{sup 4} A/cm{sup 2} at 8 kG and 40 K was obtained in the 2234 sample with many defects, while the J{sub c} dropped significantly at the same temperature and field in the near stoichiometry Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) sample with a uniform microstructure.

  1. Itinerant effects and enhanced magnetic interactions in Bi-based multilayer cuprates

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

    Dean, M. P. M.; James, A. J. A.; Walters, A. C.; Bisogni, V.; Jarrige, I.; Hücker, M.; Giannini, E.; Fujita, M.; Pelliciari, J.; Huang, Y. B.; et al

    2014-12-04

    The cuprate high temperature superconductors exhibit a pronounced trend in which the superconducting transition temperature, T c, increases with the number of CuO₂ planes, n, in the crystal structure. We compare the magnetic excitation spectrum of Bi₂₊xSr₂₋xCuO₆+δ (Bi-2201) and Bi₂Sr₂Ca₂Cu₃O₁₀₊δ (Bi-2223), with n = 1 and n = 3 respectively, using Cu L₃-edge resonant inelastic x-ray scattering (RIXS). Near the anti-nodal zone boundary we find the paramagnon energy in Bi-2223 is substantially higher than that in Bi-2201, indicating that multilayer cuprates host stronger effective magnetic exchange interactions, providing a possible explanation for the Tc vs. n scaling. In contrast, themore » nodal direction exhibits very strongly damped, almost non-dispersive excitations. As a result, we argue that this implies that the magnetism in the doped cuprates is partially itinerant in nature.« less

  2. Variable mode bi-directional and uni-directional computer communication system

    DOE Patents [OSTI]

    Cornett, Frank N.; Jenkins, Philip N.; Bowman, Terrance L.; Placek, Joseph M.; Thorson, Gregory M.

    2004-12-14

    A variable communication systems comprising a plurality of transceivers and a control circuit connected to the transceivers to configure the transceivers to operate in a bi-directional mode and a uni-directional mode at different times using different transfer methods to transfer data.

  3. Visible Light Assisted Photocatalytic Hydrogen Generation by Ta2O5/Bi2O3, TaON/Bi2O3, and Ta3N5/Bi2O3 Composites

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

    Adhikari, Shiba; Hood, Zachary D.; More, Karren Leslie; Ivanov, Ilia N.; Zhang, Lifeng; Gross, Michael; Lachgar, Abdou

    2015-06-15

    Composites comprised of two semiconducting materials with suitable band gaps and band positions have been reported to be effective at enhancing photocatalytic activity in the visible light region of the electromagnetic spectrum. Here, we report the synthesis, complete structural and physical characterizations, and photocatalytic performance of a series of semiconducting oxide composites. UV light active tantalum oxide (Ta2O5) and visible light active tantalum oxynitride (TaON) and tantalum nitride (Ta3N5) were synthesized, and their composites with Bi2O3 were prepared in situ using benzyl alcohol as solvent. The composite prepared using equimolar amounts of Bi2O3 and Ta2O5 leads to the formation ofmore » the ternary oxide, bismuth tantalate (BiTaO4) upon calcination at 1000 °C. The composites and single phase bismuth tantalate formed were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) surface area measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy, and photoluminescence. The photocatalytic activities of the catalysts were evaluated for generation of hydrogen using aqueous methanol solution under visible light irradiation (λ ≥ 420 nm). The results show that as-prepared composite photocatalysts extend the light absorption range and restrict photogenerated charge-carrier recombination, resulting in enhanced photocatalytic activity compared to individual phases. The mechanism for the enhanced photocatalytic activity for the heterostructured composites is elucidated based on observed activity, band positions calculations, and photoluminescence data.« less

  4. Pressure-dependent Optical Behaviors of Colloidal CdSe Nanoplatelets...

    Office of Scientific and Technical Information (OSTI)

    dependent Optical Behaviors of Colloidal CdSe Nanoplatelets Citation Details In-Document Search Title: Pressure-dependent Optical Behaviors of Colloidal CdSe Nanoplatelets Authors: ...

  5. Sharp inflaton potentials and bi-spectra: effects of smoothening the discontinuity

    SciTech Connect (OSTI)

    Martin, Jérôme; Sriramkumar, L.; Hazra, Dhiraj Kumar E-mail: sriram@physics.iitm.ac.in

    2014-09-01

    Sharp shapes in the inflaton potentials often lead to short departures from slow roll which, in turn, result in deviations from scale invariance in the scalar power spectrum. Typically, in such situations, the scalar power spectrum exhibits a burst of features associated with modes that leave the Hubble radius either immediately before or during the epoch of fast roll. Moreover, one also finds that the power spectrum turns scale invariant at smaller scales corresponding to modes that leave the Hubble radius at later stages, when slow roll has been restored. In other words, the imprints of brief departures from slow roll, arising out of sharp shapes in the inflaton potential, are usually of a finite width in the scalar power spectrum. Intuitively, one may imagine that the scalar bi-spectrum too may exhibit a similar behavior, i.e. a restoration of scale invariance at small scales, when slow roll has been reestablished. However, in the case of the Starobinsky model (viz. the model described by a linear inflaton potential with a sudden change in its slope) involving the canonical scalar field, it has been found that, a rather sharp, though short, departure from slow roll can leave a lasting and significant imprint on the bi-spectrum. The bi-spectrum in this case is found to grow linearly with the wavenumber at small scales, a behavior which is clearly unphysical. In this work, we study the effects of smoothening the discontinuity in the Starobinsky model on the scalar bi-spectrum. Focusing on the equilateral limit, we analytically show that, for smoother potentials, the bi-spectrum indeed turns scale invariant at suitably large wavenumbers. We also confirm the analytical results numerically using our newly developed code BINGO. We conclude with a few comments on certain related points.

  6. Future use of BI-GAS facility. Final report, Part II. [Other possible uses

    SciTech Connect (OSTI)

    Not Available

    1981-09-01

    The 120 tpd BI-GAS pilot plant, intended to produce SNG at high pressure, was completed in 1976. For the next three and a half years, the operator, Stearns-Roger Inc., was engaged in operating the plant while overcoming a series of mechanical problems that have prevented the plant from running at design capacity and pressure. Since July 1980, these problems have apparently been corrected and considerable progress was made. In late 1979, the Yates Congressional Committee directed DOE to investigate the possibility of establishing an entrained-bed gasifier test facility at the site. In January 1981, the DOE established a study group composed of DOE and UOP/SDC personnel to determine how best to use the BI-GAS facility. The group considered four possibilities: Continue operation of the facility in accordance with the technical program plan developed by DOE and Stearns-Roger; modify the plant into an entrained-bed facility for testing components and processes; mothball the facility, or dismantle the facility. The group took the view that modifying the plant into a test facility would increase substantially the amount of engineering data available to the designers of commercial gasification plants. Since it appears that syngas plants will be of commercial interest sooner than SNG plants will, it was decided that the facility should test syngas production components and processes at high pressure. Consequently, it was recommended that: Operation of the plant be continued, both to collect data and to prove the BI-GAS process, as long as the schedule of the technical program plan is met; Begin at once to prepare a detailed design for modifying the BI-GAS plant to a high-pressure, entrained flow syngas test facility; and Implement the modification plan as soon as the BI-GAS process is proven or it becomes apparent that progress is unsatisfactory.

  7. Magnetic properties of proton irradiated BiFeO{sub 3}

    SciTech Connect (OSTI)

    Han, Seungkyu; Jin Kim, Sam; Sung Kim, Chul

    2013-05-07

    The crystal structure and magnetic properties of BiFeO{sub 3} samples, proton-irradiated with 0, 10, and 20 pC/{mu}m{sup 2}, were investigated with x-ray diffraction (XRD), vibrating sample magnetometer, and Moessbauer spectroscopy measurements. From the Rietveld refinement analysis of the XRD patterns, the crystal structure of BiFeO{sub 3} is determined to be rhombohedral with the space group of R3c. We have observed the decrease in the lattice constant and oxygen occupancy with proton irradiation. The magnetization hysteresis (M-H) curves show the appearance of the weak ferromagnetic behavior in the proton irradiated BiFeO{sub 3} samples. The Moessbauer spectra of proton irradiated BiFeO{sub 3} samples at 295 K were analyzed with two-sextets (B{sub 1} and B{sub 2}) and doublet. From the isomer shift ({delta}) values, ionic states were determined to be Fe{sup 3+}. Compared to non-irradiated sample, having the antiferromagnetic area ratio (two-sextets) of 45.47, 54.53% the antiferromagnetic and paramagnetic area ratios (doublet) of 10 and 20 pC/{mu}m{sup 2} proton irradiated BiFeO{sub 3} samples are 41.36, 51.26, and 7.38% and 41.03, 50.90, and 8.07%, respectively. Our experimental observation suggests that the increase in the paramagnetic area ratio is due to the disappearance of superexchange interaction, resulted from the removal of the oxygen with proton irradiation. Also, the appearance of the weak ferromagnetic behavior is caused by the breaking of the antiferromagnetic coupling.

  8. Insulation and Heat Treatment of Bi-2212 Wire for Wind-and-React Coils

    SciTech Connect (OSTI)

    Peter K. F. Hwang

    2007-10-22

    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2" dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  9. Shock compression behavior of bi-material powder composites with disparate melting temperatures

    SciTech Connect (OSTI)

    Sullivan, Kyle T.; Swift, Damian; Barham, Matthew; Stlken, James; Kuntz, Joshua; Kumar, Mukul

    2014-01-14

    Laser driven experiments were used to investigate the shock compression behavior of powder processed Bismuth/Tungsten (Bi/W) composite samples. The constituents provide different functionality to the composite behavior as Bi could be shock melted at the pressures attained in this work, while the W could not. Samples were prepared by uniaxial pressing, and the relative density was measured as a function of particle size, applied pressure, and composition for both hot and cold pressing conditions. This resulted in sample densities between 73% and 99% of the theoretical maximum density, and also noticeable differences in microstructure in the hot and cold pressed samples. The compression waves were generated with a 1.3 1.3?mm square spot directly onto the surface of the sample, using irradiances between 10{sup 12} and 10{sup 13}?W/cm{sup 2}, which resulted in calculated peak pressures between 50 and 150?GPa within a few micrometers. Sample recovery and post-mortem analysis revealed the formation of a crater on the laser drive surface, and the depth of this crater corresponded to the depth to which the Bi had been melted. The melt depth was found to be primarily a function of residual porosity and composition, and ranged from 167 to 528??m. In general, a higher porosity led to a larger melt depth. Direct numerical simulations were performed, and indicated that the observed increase in melt depth for low-porosity samples could be largely attributed to increased heating associated with work done for pore collapse. However, the relative scaling was sensitive to composition, with low volume fraction Bi samples exhibiting a much stronger dependence on porosity than high Bi content samples. Select samples were repeated using an Al foil ablator, but there were no noticeable differences ensuring that the observed melting was indeed pressure-driven and was not a result of direct laser heating. The resultant microstructures and damage near the spall surface were also

  10. MicroRNAs let-7b/i suppress human glioma cell invasion and migration by targeting IKBKE directly

    SciTech Connect (OSTI)

    Tian, Yuan; Hao, Shaobo; Ye, Minhua; Zhang, Anling; Nan, Yang; Wang, Guangxiu; Jia, Zhifan; Yu, Kai; Guo, Lianmei; Pu, Peiyu; Huang, Qiang; Zhong, Yue

    2015-03-06

    We demonstrated that IKBKE is overexpressed in human gliomas and that the downregulation of IKBKE markedly inhibits the proliferative and invasive abilities of glioma cells, which is consistent with the results reported by several different research groups. Therefore, IKBKE represents a promising therapeutic target for the treatment of glioma. In the present study, we verified that the microRNAs let-7b and let-7i target IKBKE through luciferase assays and found that let-7b/i mimics can knock down IKBKE and upregulate E-cadherin through western blot analysis. Moreover, the expression levels of let-7b/i were significantly lower in glioma cell lines than that in normal brain tissues, as determined by quantitative real-time PCR. Furthermore, let-7b/i inhibit the invasion and migration of glioma cells, as determined through wound healing and Transwell assays. The above-mentioned data suggest that let-7b/i inhibit the invasive ability of glioma cells by directly downregulating IKBKE and indirectly upregulating E-cadherin. - Highlights: • Let-7b and let-7i are downregulated in glioma cell lines. • IKBKE is a target gene of let-7b/i. • Let-7b/i inhibit the invasion and migration of glioma cells. • Let-7b/i upregulate E-cadherin by downregulating IKBKE.