Powered by Deep Web Technologies
Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Blue Dots Team Transits Working Group Review  

E-Print Network [OSTI]

Transiting planet systems offer an unique opportunity to observationally constrain proposed models of the interiors (radius, composition) and atmospheres (chemistry, dynamics) of extrasolar planets. The spectacular successes of ground-based transit surveys (more than 60 transiting systems known to-date) and the host of multi-wavelength, spectro-photometric follow-up studies, carried out in particular by HST and Spitzer, have paved the way to the next generation of transit search projects, which are currently ongoing (CoRoT, Kepler), or planned. The possibility of detecting and characterizing transiting Earth-sized planets in the habitable zone of their parent stars appears tantalizingly close. In this contribution we briefly review the power of the transit technique for characterization of extrasolar planets, summarize the state of the art of both ground-based and space-borne transit search programs, and illustrate how the science of planetary transits fits within the Blue Dots perspective.

Sozzetti, A; Alonso, R; Blank, D L; Catala, C; Deeg, H; Grenfell, J L; Hellier, C; Latham, D W; Minniti, D; Pont, F; Rauer, H

2009-01-01T23:59:59.000Z

2

Strain-induced fundamental optical transition in (In,Ga)As/GaP quantum dots  

SciTech Connect (OSTI)

The nature of the ground optical transition in an (In,Ga)As/GaP quantum dot is thoroughly investigated through a million atoms supercell tight-binding simulation. Precise quantum dot morphology is deduced from previously reported scanning-tunneling-microscopy images. The strain field is calculated with the valence force field method and has a strong influence on the confinement potentials, principally, for the conduction band states. Indeed, the wavefunction of the ground electron state is spatially confined in the GaP matrix, close to the dot apex, in a large tensile strain region, having mainly Xz character. Photoluminescence experiments under hydrostatic pressure strongly support the theoretical conclusions.

Robert, C., E-mail: cedric.robert@insa-rennes.fr, E-mail: cedric.robert@tyndall.ie; Pedesseau, L.; Cornet, C.; Jancu, J.-M.; Even, J.; Durand, O. [Université Européenne de Bretagne, INSA Rennes, France and CNRS, UMR 6082 Foton, 20 Avenue des Buttes de Coësmes, 35708 Rennes (France)] [Université Européenne de Bretagne, INSA Rennes, France and CNRS, UMR 6082 Foton, 20 Avenue des Buttes de Coësmes, 35708 Rennes (France); Nestoklon, M. O. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)] [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Pereira da Silva, K. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain) [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); Departamento de Física, Universidade Federal do Ceará, P.O. Box 6030, Fortaleza–CE, 60455-970 (Brazil); Alonso, M. I. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain)] [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); Goñi, A. R. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain) [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); ICREA, Passeig Lluís Companys 23, 08010 Barcelona (Spain); Turban, P. [Equipe de Physique des Surfaces et Interfaces, Institut de Physique de Rennes UMR UR1-CNRS 6251, Université de Rennes 1, F-35042 Rennes Cedex (France)] [Equipe de Physique des Surfaces et Interfaces, Institut de Physique de Rennes UMR UR1-CNRS 6251, Université de Rennes 1, F-35042 Rennes Cedex (France)

2014-01-06T23:59:59.000Z

3

Spectrum of surface plasmons excited by spontaneous quantum dot transitions  

SciTech Connect (OSTI)

We consider quantum fluctuations of near fields of a quantum emitter (two-level system (TLS) with population inversion sustained by incoherent pumping) in the near-field zone of a plasmon (metallic) nanoparticle. The spectrum of surface plasmons excited by spontaneous transitions in the quantum emitter is obtained below the lasing threshold of such a system (spaser) in the approximation of a small number of plasmons. It is shown that the relaxation rate is the sum of the quantum emitter's rates of relaxation to its thermal reservoir and the plasmon cavity. The resulting dependence of the average number of plasmons on the pump intensity indicates the nonthreshold nature of the process.

Andrianov, E. S., E-mail: andrianov.es@mipt.ru; Pukhov, A. A., E-mail: pukhov@mail.ru; Dorofeenko, A. V.; Vinogradov, A. P. [Russian Academy of Sciences, Institute of Theoretical and Applied Electrodynamics (Russian Federation)] [Russian Academy of Sciences, Institute of Theoretical and Applied Electrodynamics (Russian Federation); Lisyansky, A. A. [Queens College of the City University of New York, Department of Physics (United States)] [Queens College of the City University of New York, Department of Physics (United States)

2013-08-15T23:59:59.000Z

4

Transition to Landau levels in graphene quantum dots F. Libisch,1,* S. Rotter,1 J. Gttinger,2 C. Stampfer,2,3 and J. Burgdrfer1  

E-Print Network [OSTI]

Transition to Landau levels in graphene quantum dots F. Libisch,1,* S. Rotter,1 J. Güttinger,2 C the electronic eigenstates of graphene quantum dots of realistic size up to 80 nm diameter in the presence-level regime at high fields. Details of this transition sensitively depend on the underlying graphene lattice

Florian, Libisch

5

Transition to Landau levels in graphene quantum dots F. Libisch, 1, * S. Rotter, 1 J. Gttinger, 2 C. Stampfer, 2,3 and J. Burgdrfer 1  

E-Print Network [OSTI]

Transition to Landau levels in graphene quantum dots F. Libisch, 1, * S. Rotter, 1 J. Güttinger, 2 investigate the electronic eigenstates of graphene quantum dots of realistic size #up to 80 nm diameter graphene lattice structure, bulk defects, and localization effects at the edges. Key to the understanding

Florian, Libisch

6

Study of valence-band intersublevel transitions in InAs/GaAs quantum dots-in-well infrared photodetectors  

SciTech Connect (OSTI)

The n-type quantum dot (QD) and dots-in-well (DWELL) infrared photodetectors, in general, display bias-dependent multiple-band response as a result of optical transitions between different quantum levels. Here, we present a unique characteristic of the p-type hole response, a well-preserved spectral profile, due to the much reduced tunneling probability of holes compared to electrons. This feature remains in a DWELL detector, with the dominant transition contributing to the response occurring between the QD ground state and the quantum-well states. The bias-independent response will benefit applications where single-color detection is desired and also allows achieving optimum performance by optimizing the bias.

Lao, Yan-Feng; Wolde, Seyoum; Unil Perera, A. G., E-mail: uperera@gsu.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States); Zhang, Y. H.; Wang, T. M. [Key Laboratory of Artificial Structures and Quantum Control, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Kim, J. O.; Schuler-Sandy, Ted; Tian, Zhao-Bing; Krishna, S. S. [Center for High Technology Materials, Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87106 (United States)

2014-04-28T23:59:59.000Z

7

Physica E 32 (2006) 1416 Tuning the cross-gap transition energy of a quantum dot  

E-Print Network [OSTI]

; Spectroscopy; Energy tuning Self-assembled semiconductor quantum dots (QDs) are of great interest for quantum resistance bridge circuit in combination with a lock in amplifier is used to measure the change in resistance

Ludwig-Maximilians-Universität, München

2006-01-01T23:59:59.000Z

8

Theoretical study of intraband optical transitions in conduction band of dot-in-a-well system  

SciTech Connect (OSTI)

We study numerically absorption optical spectra of n-doped InAs/In{sub 015}Ga{sub 085}As/GaAs quantum dot-in-a-well systems. The absorption spectra are mainly determined by the size of a quantum dot and have weak dependence on the thickness of quantum well and position of the dot in a well. The dot-in-a-well system is sensitive to both in-plane and out-of-plane polarizations of the incident light with much stronger absorption intensities for the in-plane-polarized light. The absorption spectrum of in-plane-polarized light has also a multi-peak structure with two or three peaks of comparable intensities, while the absorption spectrum of out-of-plane polarized light has a single well-pronounced peak.

Chaganti, Venkata R.; Apalkov, Vadym [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30302 USA. (Georgia)] [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30302 USA. (Georgia)

2014-02-15T23:59:59.000Z

9

The effects of wetting layer on electronic and optical properties of intersubband P-to-S transitions in strained dome-shaped InAs/GaAs quantum dots  

SciTech Connect (OSTI)

The authors report on the impact of wetting layer thickness and quantum dot size on the electronic and optical properties of dome-shaped InAs/GaAs quantum dots (QDs) with strained potential. Two wetting layer thicknesses of 0.5 and 2.0 nm were compared. A strong size dependence of P-to-S transition energy, transition dipole moment, oscillator strength, and linear and third-order nonlinear susceptibilities were concluded. The P-to-S transition dipole moment was shown to be purely in-plane polarization. The linear and nonlinear absorption and dispersion showed a red shift when the wetting layer thickness was increased. Our results revealed that the nonlinear susceptibility is much more sensitive to QD size compared to the linear susceptibility. An interpretation of the results was presented based on the probability density of finding the electron inside the dot and wetting layer. The results are in good agreement with previously reported experimental data.

Shahzadeh, Mohammadreza; Sabaeian, Mohammad, E-mail: sabaeian@scu.ac.ir [Physics Department, Faculty of Science, Shahid Chamran University of Ahvaz (Iran, Islamic Republic of)

2014-06-15T23:59:59.000Z

10

Grays Harbor PUD- Net Metering  

Broader source: Energy.gov [DOE]

Grays Harbor PUD's net-metering program differs slightly from what is required by Washington state law in that Grays Harbor PUD reimburses customers for net excess generation (NEG), at the end of...

11

Enhancing structural transition by carrier and quantum confinement: Stabilization of cubic InN quantum dots by Mn incorporation  

SciTech Connect (OSTI)

We demonstrate in this work controllable synthesis of cubic InN nanocrystals through Mn doping. We show that the pristine nanocrystal has the wurtzite structure, but can be converted into the zinc-blende (ZB) structure when it is doped with Mn. Our first-principles calculations show that the phase transition is caused by the stronger p-d coupling between the host p valence state and the impurity d level in the ZB structure, which makes the hole generation in the ZB structure easier. Quantum confinement in the nanocrystals further enhanced this effect. This observation lays an important foundation for defects control of crystal phases.

Meng, Xiuqing; Wu, Fengmin [Zhejiang Normal University, Jinhua, Zhejiang Province 321004 (China)] [Zhejiang Normal University, Jinhua, Zhejiang Province 321004 (China); Chen, Zhanghui; Li, Shu-Shen [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)] [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Chen, Zhuo [Department of Physics, Beijing Institute of Technology, Beijing 100081 (China)] [Department of Physics, Beijing Institute of Technology, Beijing 100081 (China); Li, Jingbo, E-mail: jbli@semi.ac.cn, E-mail: swei@nrel.gov [Zhejiang Normal University, Jinhua, Zhejiang Province 321004 (China) [Zhejiang Normal University, Jinhua, Zhejiang Province 321004 (China); State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Wu, Junqiao [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Wei, Su-Huai, E-mail: jbli@semi.ac.cn, E-mail: swei@nrel.gov [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)] [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

2013-12-16T23:59:59.000Z

12

Advanced gray rod control assembly  

DOE Patents [OSTI]

An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

2013-09-17T23:59:59.000Z

13

Grays River Watershed Geomorphic Analysis  

SciTech Connect (OSTI)

This investigation, completed for the Pacific Northwest National Laboratory (PNNL), is part of the Grays River Watershed and Biological Assessment commissioned by Bonneville Power Administration under project number 2003-013-00 to assess impacts on salmon habitat in the upper Grays River watershed and present recommendations for habitat improvement. This report presents the findings of the geomorphic assessment and is intended to support the overall PNNL project by evaluating the following: 􀂃 The effects of historical and current land use practices on erosion and sedimentation within the channel network 􀂃 The ways in which these effects have influenced the sediment budget of the upper watershed 􀂃 The resulting responses in the main stem Grays River upstream of State Highway 4 􀂃 The past and future implications for salmon habi

Geist, David R.

2005-04-30T23:59:59.000Z

14

Gray molasses cooling of 39 K to a high phase-space density  

E-Print Network [OSTI]

present new techniques in cooling 39 K atoms using laser light close to the D1 transition. First, a newepl draft Gray molasses cooling of 39 K to a high phase-space density G. Salomon1 , L. Fouch´e1 , P, IOGS, CNRS, 351 cours de la Lib´eration, 33405 Talence, France PACS 37.10.De ­ Atom cooling methods

Paris-Sud XI, Université de

15

Grays Harbor PUD- Solar Water Heater Loan  

Broader source: Energy.gov [DOE]

Since October 2001, Grays Harbor PUD has offered a low-interest loan program (currently 4.0%) for the installation of solar water heaters. Loans are available for the installation of solar...

16

Grays Harbor PUD- Solar Water Heater Rebate  

Broader source: Energy.gov [DOE]

Since October 2001, Grays Harbor PUD has offered a rebate program for the installation of solar water heaters. Rebates of $600 are available for the installation of solar collectors of 40 square...

17

Quantum dot device tunable from single to triple dot system  

SciTech Connect (OSTI)

We present a lateral quantum dot device which has a tunable number of quantum dots. Depending on easily tunable gate voltages, one, two or three quantum dots are found. They are investigated in transport and charge detection.

Rogge, M. C.; Haug, R. J. [Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover (Germany); Pierz, K. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

2013-12-04T23:59:59.000Z

18

Dot Density Maps Dot density maps, or dot maps, portray the geographic distribution of discrete phenomena  

E-Print Network [OSTI]

Dot Density Maps Dot density maps, or dot maps, portray the geographic distribution of discrete for representing geographic patterns. Dot density maps are particularly useful for understanding global distribution of the mapped phenomenon and comparing relative densities of different regions on the map. Dot

Klippel, Alexander

19

Corporate Gray Military Officer Job Fair | Department of Energy  

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

Corporate Gray Military Officer Job Fair Corporate Gray Military Officer Job Fair September 11, 2014 8:00AM to 1:30PM EDT Location: 6715 Commerce Street, Springfield, VA 22150 POC:...

20

Greentree Reservoir Management Matthew J. Gray  

E-Print Network [OSTI]

1 Greentree Reservoir Management Matthew J. Gray University of Tennessee Hardwood Bottomlands in Openings Guy Baldassarre Should Manage for Forest Openings >1 acre #12;4 Other Important Functions Bottomline on Bottomlands Hardwood bottomlands are critical ecosystems that play an integral role

Gray, Matthew

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Self-assembly of silicide quantum dot arrays on stepped silicon surfaces by reactive epitaxy  

E-Print Network [OSTI]

investigated on the epitaxy and self- organization of laterally nanostructured transition metal TM silicideSelf-assembly of silicide quantum dot arrays on stepped silicon surfaces by reactive epitaxy L to be a flexible and a convenient method for the preparation of dense arrays of Co silicide quantum dots

Ortega, Enrique

22

Absorption and photoluminescence spectroscopy on a single self-assembled charge-tunable quantum dot  

E-Print Network [OSTI]

Absorption and photoluminescence spectroscopy on a single self-assembled charge-tunable quantum dot PL and absorption spectroscopy on the same single self- assembled quantum dot in a charge the corresponding transition in absorption. We have developed a model of the Coulomb blockade to account

Ludwig-Maximilians-Universität, München

23

Grays Harbor PUD- Non-Residential Energy Efficiency Rebate Program  

Broader source: Energy.gov [DOE]

Grays Harbor PUD's Non-Residential Rebate Program offers financial incentives to its commercial, agricultural, industrial, and institutional customers for the installation of energy efficient...

24

Gray County Wind Farm | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to:Photon Place: Golden, COIndiana JumpGray County Wind Farm Jump

25

Grays Harbor Demonstration Project | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to:Photon Place: Golden, COIndiana JumpGray County Wind Farm

26

A quantum dot heterojunction photodetector  

E-Print Network [OSTI]

This thesis presents a new device architecture for photodetectors utilizing colloidally grown quantum dots as the principle photo-active component. We implement a thin film of cadmium selenide (CdSe) quantum dot sensitizers, ...

Arango, Alexi Cosmos, 1975-

2005-01-01T23:59:59.000Z

27

Certificate Program in Transit Management and Operations Allan Byam, Krystal Oldread, UMass Transit Services  

E-Print Network [OSTI]

Certificate Program in Transit Management and Operations Allan Byam, Krystal Oldread, UMass TransitDOT · Managed by the First Transit Management group · 400 buses, 26.4 million passengers/yr, travel 12 million-level managers ! Leadership APTA, National Transit Institute, Professional Certifications ! Programs for skilled

Massachusetts at Amherst, University of

28

Astragalus arrectus Gray Palouse milk-vetch  

E-Print Network [OSTI]

General Description: Erect perennial with a woody taproot and shortly forking caudex; stems numerous, in clumps, 8-16 in. long; herbage green or gray-green; leaves pea-like, glabrous above, 3 to 9 inches long; stipules 3/16 to 5/16 inch long; leaflets mostly 21-31, linear-oblong, lanceolate, 5/16 to inch long; peduncles straight, 4-10 inches long; racemes 15 to 35 flowered; flowers erect, yellowish-white, drying yellowish, about inch long; calyx inch long, the tube c inch long, the teeth about 1/ 16 inch long; petals irregularly graduated, the wings about c inch longer than the abruptly recurved banner, the keel inch long; the pod erect, stipitate, b to 1 inch long, c to inch thick. Identification Tips: Most easily recognized by its irregularly proportioned flowers which ascend from the raceme-axis at an angle of about 45 degrees and are followed by erect, stipitate, dorsally grooved pods of thick texture, pubescent with black or gray-brown, rarely white hairs. The species could be confused with A. leibergii in parts of its range. The flower of A. leibergii is white while the flower of A. arrectus is yellowish white, drying yellow. Also the leaflets of A. arrectus are glabrous above while A. leibergii leaflets are equally pubescent on both sides. Phenology: Flowers from late April to early July. Range: Regional endemic; found along the Lower Snake, Clearwater, and Palouse Rivers in Idaho, and scattered throughout

Fabaceae (pea Family; Astragalus Arrectus; Palouse Milk-vetch; Status Statethreatened; Rank Ggs

29

Enhanced Two-Photon Processes in Quantum Dots inside Photonic Crystal Nanocavities and Quantum Information Processing Applications  

E-Print Network [OSTI]

We show that the two-photon transition rates of quantum dots coupled to nanocavities are enhanced by up to 8 orders of magnitude relative to quantum dots in bulk host. We then propose how to take advantage of this enhancement to implement coherent quantum dot excitation by two-photon absorption, entangled photon pair generation by two-photon spontaneous emission, and single-photon generation at telecommunication wavelengths by two-photon stimulated and spontaneous emission.

Ziliang Lin; Jelena Vuckovic

2009-07-02T23:59:59.000Z

30

Femtosecond gain and index dynamics in an InAs/InGaAsP quantum dot amplifier  

E-Print Network [OSTI]

Femtosecond gain and index dynamics in an InAs/InGaAsP quantum dot amplifier operating at 1.55 µm and refractive index dynamics of an InAs/InGaAsP self-assembled quantum dot semiconductor optical amplifier (SOA-carrier absorption and stimulated transition processes. ©2006 Optical Society of America OCIS codes: (320

Mojahedi, Mohammad

31

Nontoxic quantum dot research improves solar cells  

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

Nontoxic quantum dot research improves solar cells Nontoxic quantum dot research improves solar cells Solar cells made with low-cost, nontoxic copper-based quantum dots can achieve...

32

Gray Matter Is Targeted in First-Attack Multiple Sclerosis  

SciTech Connect (OSTI)

The cause of multiple sclerosis (MS), its driving pathogenesis at the earliest stages, and what factors allow the first clinical attack to manifest remain unknown. Some imaging studies suggest gray rather than white matter may be involved early, and some postulate this may be predictive of developing MS. Other imaging studies are in conflict. To determine if there was objective molecular evidence of gray matter involvement in early MS we used high-resolution mass spectrometry to identify proteins in the cerebrospinal fluid (CSF) of first-attack MS patients (two independent groups) compared to established relapsing remitting (RR) MS and controls. We found that the CSF proteins in first-attack patients were differentially enriched for gray matter components (axon, neuron, synapse). Myelin components did not distinguish these groups. The results support that gray matter dysfunction is involved early in MS, and also may be integral for the initial clinical presentation.

Schutzer, Steven E.; Angel, Thomas E.; Liu, Tao; Schepmoes, Athena A.; Xie, Fang; Bergquist, Jonas P.; Vecsei, Lazlo'; Zadori, Denes; Camp, David G.; Holland, Bart K.; Smith, Richard D.; Coyle, Patricia K.

2013-09-10T23:59:59.000Z

33

Essays on Supply Chains Facing Competition from Gray Markets  

E-Print Network [OSTI]

University. Bangkok Post. 2010. BMW Thailand to No Longernews-amp-analysis/ bmw-thailand-no-longer-service-gray-2011b). Prior to Mercedes-Benz, BMW Thailand had decided to

Iravani, Foad

2012-01-01T23:59:59.000Z

34

A comparison between semi-spheroid- and dome-shaped quantum dots coupled to wetting layer  

SciTech Connect (OSTI)

During the epitaxial growth method, self-assembled semi-spheroid-shaped quantum dots (QDs) are formed on the wetting layer (WL). However for sake of simplicity, researchers sometimes assume semi-spheroid-shaped QDs to be dome-shaped (hemisphere). In this work, a detailed and comprehensive study on the difference between electronic and transition properties of dome- and semi-spheroid-shaped quantum dots is presented. We will explain why the P-to-S intersubband transition behaves the way it does. The calculated results for intersubband P-to-S transition properties of quantum dots show two different trends for dome-shaped and semi-spheroid-shaped quantum dots. The results are interpreted using the probability of finding electron inside the dome/spheroid region, with emphasis on the effects of wetting layer. It is shown that dome-shaped and semi-spheroid-shaped quantum dots feature different electronic and transition properties, arising from the difference in lateral dimensions between dome- and semi-spheroid-shaped QDs. Moreover, an analogy is presented between the bound S-states in the quantum dots and a simple 3D quantum mechanical particle in a box, and effective sizes are calculated. The results of this work will benefit researchers to present more realistic models of coupled QD/WL systems and explain their properties more precisely.

Shahzadeh, Mohammadreza; Sabaeian, Mohammad, E-mail: Sabaeian@scu.ac.ir [Physics Department, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, 61357-43135 (Iran, Islamic Republic of)

2014-06-15T23:59:59.000Z

35

Global Warming: Connecting the Dots  

E-Print Network [OSTI]

Global Warming: Connecting the Dots from Causes to Solutions* Jim Hansen 26 February 2007 National://www.columbia.edu/~jeh1/worldwatch_nov2006.pdf) 5. Communicating dangers and opportunities in global warming, Amer-16, 2006. (http://pubs.giss.nasa.gov/docs/2006/2006_Hansen.pdf) 8. Global warming: Connecting the dots from

Hansen, James E.

36

Financial and Technical Resources for Completing Energy Efficiency Projects - The DOT/FTA Perspective  

E-Print Network [OSTI]

Financial and Technical Resources for Completing Energy Efficiency Projects ? The DOT/FTA Perspective Don Koski, FTA Region VI CATEE Conference November 9, 2011 ?FTA is part of the US DOT with a mission to support public transit through... of Transportation ? TIGER Grants ? FTA Programs ? FHWA Flex Funding ? United We Ride ? FHWA Livability Efforts ? State/Metro Planning ? Railroad Infrastructure U.S. Department of Agriculture ? Rural Efforts + Infrastructure Investment ?Urban/Rural...

Koski, D.

2011-01-01T23:59:59.000Z

37

On 3-gauge transformations, 3-curvatures, and Gray-categories  

SciTech Connect (OSTI)

In the 3-gauge theory, a 3-connection is given by a 1-form A valued in the Lie algebra g, a 2-form B valued in the Lie algebra h, and a 3-form C valued in the Lie algebra l, where (g,h,l) constitutes a differential 2-crossed module. We give the 3-gauge transformations from one 3-connection to another, and show the transformation formulae of the 1-curvature 2-form, the 2-curvature 3-form, and the 3-curvature 4-form. The gauge configurations can be interpreted as smooth Gray-functors between two Gray 3-groupoids: the path 3-groupoid P{sub 3}(X) and the 3-gauge group G{sup L} associated to the 2-crossed module L, whose differential is (g,h,l). The derivatives of Gray-functors are 3-connections, and the derivatives of lax-natural transformations between two such Gray-functors are 3-gauge transformations. We give the 3-dimensional holonomy, the lattice version of the 3-curvature, whose derivative gives the 3-curvature 4-form. The covariance of 3-curvatures easily follows from this construction. This Gray-categorical construction explains why 3-gauge transformations and 3-curvatures have the given forms. The interchanging 3-arrows are responsible for the appearance of terms with the Peiffer commutator (, )

Wang, Wei, E-mail: wwang@zju.edu.cn [Department of Mathematics, Zhejiang University, Zhejiang 310027 (China)] [Department of Mathematics, Zhejiang University, Zhejiang 310027 (China)

2014-04-15T23:59:59.000Z

38

New framework hydrous silicate K{sub 3}Sc[Si{sub 3}O{sub 9}] {center_dot} H{sub 2}O related to the high-temperature anhydrous silicate K{sub 3}Ho[Si{sub 3}O{sub 9}] and symmetry analysis of a phase transition with prediction of structures  

SciTech Connect (OSTI)

Crystals of a new framework silicate K{sub 3}Sc[Si{sub 3}O{sub 9}] {center_dot} H{sub 2}O, space group Pm2{sub 1}n (nonstandard setting of space group Pmn2{sub 1} = C{sub 2v}{sup 7}), are obtained under hydrothermal conditions. The structure is determined without preliminary knowledge of the chemical formula. The absolute configuration is determined. The structure is close to that of the high-temperature K{sub 3}Ho[Si{sub 3}O{sub 9}] phase, which was obtained upon the heating of K{sub 3}HoSi{sub 3}O{sub 8}(OH){sub 2}. This structural similarity is due to the specific conditions of synthesis and an analogous formula, where holmium is replaced by scandium. A symmetry analysis shows that the high local symmetry of a block (rod) is responsible for the first-order phase transition of both the order-disorder (OD) and displacement type. The number of structures in which the simplest and high-symmetry layers are multiplied by different symmetry elements are predicted.

Belokoneva, E. L., E-mail: elbel@geol.msu.ru; Zorina, A. P.; Dimitrova, O. V. [Moscow State University, Faculty of Geology (Russian Federation)

2013-07-15T23:59:59.000Z

39

A Mechanism for Detecting Gray Hole Attacks on Synchrophasor Data  

E-Print Network [OSTI]

in smart grids [1]. Phasor measurement unit (PMU) or synchrophasor data serves to facilitate a number. This paper addresses the problem of securing PMU data against packet dropping or gray hole attacks in the network on PMU data can easily lead to the loss of observability of the system and render useless a number

Sikdar, Biplab

40

All inorganic colloidal quantum dot LEDs  

E-Print Network [OSTI]

This thesis presents the first colloidal quantum dot light emitting devices (QD-LEDs) with metal oxide charge transport layers. Colloidally synthesized quantum dots (QDs) have shown promise as the active material in ...

Wood, Vanessa Claire

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Toolbox Safety Talk DOT Materials of Trade  

E-Print Network [OSTI]

: Corrosive Battery acid, Descaler Class 9: Miscellaneous Lithium batteries, ORM-D #12;Toolbox Safety Talk DOT

Pawlowski, Wojtek

42

Enhanced EP halftones with hexagonal dot packing  

E-Print Network [OSTI]

Enhanced EP halftones with hexagonal dot packing Tomasz J. Cholewo, Steve Weed, Brian Cooper advantages for electropho- tographic (EP) printing over conventional dot placement on a square grid [1] reported that hexagonal dot packing could have some unique benefits for EP printing. These were

Cholewo, Tomasz

43

Double superexchange in quantum dot mesomaterials  

E-Print Network [OSTI]

of defects,2 and resist oxidation better.3 In addition, these small dots use their slice of the solar. An idea that has been explored for larger dots is to encapsulate them within an inorganic amorphous matrix yet to be achieved. A second approach is to encapsulate the dots within an organic polymer blend.12

Wu, Zhigang

44

Quasiresonant Excitation of InP/InGaP Quantum Dots Using Second Harmonic Generated in a Photonic Crystal Cavity  

E-Print Network [OSTI]

Indistinguishable single photons are necessary for quantum information processing applications. Resonant or quasiresonant excitation of single quantum dots provides greater single photon indistinguishability than incoherent pumping, but is also more challenging experimentally. Here, we demonstrate high signal to noise quasiresonant excitation of InP/InGaP quantum dots. The excitation is provided via second harmonic generated from a telecommunications wavelength laser resonant with the fundamental mode of a photonic crystal cavity, fabricated at twice the quantum dot transition wavelength. The second harmonic is generated using the \\chi(2) nonlinearity of the InGaP material matrix.

Sonia Buckley; Kelley Rivoire; Fariba Hatami; Jelena Vuckovic

2012-10-03T23:59:59.000Z

45

Discrete Mathematics and Theoretical Computer Science DMTCS vol. 9:2, 2007, 145152 Gray code order for Lyndon words  

E-Print Network [OSTI]

Discrete Mathematics and Theoretical Computer Science DMTCS vol. 9:2, 2007, 145­152 Gray code order order yields a Gray code on the Lyndon family. In this paper we give a positive answer. More precisely and Lyndon words in Gray code order. Keywords: Lyndon words, Gray codes, generating algorithms 1 Introduction

Paris-Sud XI, Université de

46

23. Gray{Scott equations Patterns are everywhere in nature. Examples include spots on butter ies, stripes on zebras, tri-  

E-Print Network [OSTI]

23. Gray{Scott equations Patterns are everywhere in nature. Examples include spots on butter ies variety. The Gray{Scott equations were formulated originally by Gray and Scott in 1983; we shall advantage of this principle. References P. Gray and S. K. Scott, papers in Chem. Eng. Sci. 38 (1983), 29

Trefethen, Nick

47

Grays River Watershed and Biological Assessment Final Report 2006.  

SciTech Connect (OSTI)

The Grays River Watershed and Biological Assessment was funded to address degradation and loss of spawning habitat for chum salmon (Onchorhynchus keta) and fall Chinook salmon (Onchoryhnchus tshawytscha). In 1999, the National Marine Fisheries Service listed lower Columbia River chum salmon as a threatened Evolutionarily Significant Unit (ESU) under the Endangered Species Act of 1973 (ESA). The Grays River watershed is one of two remaining significant chum salmon spawning locations in this ESU. Runs of Grays River chum and Chinook salmon have declined significantly during the past century, largely because of damage to spawning habitat associated with timber harvest and agriculture in the watershed. In addition, approximately 20-25% of the then-remaining chum salmon spawning habitat was lost during a 1999 channel avulsion that destroyed an important artificial spawning channel operated by the Washington Department of Fish and Wildlife (WDFW). Although the lack of stable, high-quality spawning habitat is considered the primary physical limitation on Grays River chum salmon production today, few data are available to guide watershed management and channel restoration activities. The objectives of the Grays River Watershed and Biological Assessment project were to (1) perform a comprehensive watershed and biological analysis, including hydrologic, geomorphic, and ecological assessments; (2) develop a prioritized list of actions that protect and restore critical chum and Chinook salmon spawning habitat in the Grays River based on comprehensive geomorphic, hydrologic, and stream channel assessments; and (3) gain a better understanding of chum and Chinook salmon habitat requirements and survival within the lower Columbia River and the Grays River. The watershed-based approach to river ecosystem restoration relies on a conceptual framework that describes general relationships between natural landscape characteristics, watershed-scale habitat-forming processes, aquatic habitat conditions, and biological integrity. In addition, human land-use impacts are factored into the conceptual model because they can alter habitat quality and can disrupt natural habitat-forming processes. In this model (Figure S.1), aquatic habitat--both instream and riparian--is viewed as the link between watershed conditions and biologic responses. Based on this conceptual model, assessment of habitat loss and the resultant declines in salmonid populations can be conducted by relating current and historical (e.g., natural) habitat conditions to salmonid utilization, diversity, and abundance. In addition, assessing disrupted ecosystem functions and processes within the watershed can aid in identifying the causes of habitat change and the associated decline in biological integrity. In this same way, restoration, enhancement, and conservation projects can be identified and prioritized. A watershed assessment is primarily a landscape-scale evaluation of current watershed conditions and the associated hydrogeomorphic riverine processes. The watershed assessment conducted for this project focused on watershed processes that form and maintain salmonid habitat. Landscape metrics describing the level of human alteration of natural ecosystem attributes were used as indicators of water quality, hydrology, channel geomorphology, instream habitat, and biotic integrity. Ecological (watershed) processes are related to and can be predicted based on specific aspects of spatial pattern. This study evaluated the hydrologic regime, sediment delivery regime, and riparian condition of the sub-watersheds that comprise the upper Grays River watershed relative to their natural range of conditions. Analyses relied primarily on available geographic information system (GIS) data describing landscape characteristics such as climate, vegetation type and maturity, geology and soils, topography, land use, and road density. In addition to watershed-scale landscape characteristics, the study area was also evaluated on the riparian scale, with appropriate landscape variables analyzed within

May, Christopher W.; McGrath, Kathleen E.; Geist, David R. [Pacific Northwest National Laboratory; Abbe, Timothy; Barton, Chase [Herrera Environmental Consultants, Inc.

2008-02-04T23:59:59.000Z

48

Grays River Watershed and Biological Assessment, 2006 Final Report.  

SciTech Connect (OSTI)

The Grays River Watershed and Biological Assessment was funded to address degradation and loss of spawning habitat for chum salmon (Onchorhynchus keta) and fall Chinook salmon (Onchoryhnchus tshawytscha). In 1999, the National Marine Fisheries Service listed lower Columbia River chum salmon as a threatened Evolutionarily Significant Unit (ESU) under the Endangered Species Act of 1973 (ESA). The Grays River watershed is one of two remaining significant chum salmon spawning locations in this ESU. Runs of Grays River chum and Chinook salmon have declined significantly during the past century, largely because of damage to spawning habitat associated with timber harvest and agriculture in the watershed. In addition, approximately 20-25% of the then-remaining chum salmon spawning habitat was lost during a 1999 channel avulsion that destroyed an important artificial spawning channel operated by the Washington Department of Fish and Wildlife (WDFW). Although the lack of stable, high-quality spawning habitat is considered the primary physical limitation on Grays River chum salmon production today, few data are available to guide watershed management and channel restoration activities. The objectives of the Grays River Watershed and Biological Assessment project were to (1) perform a comprehensive watershed and biological analysis, including hydrologic, geomorphic, and ecological assessments; (2) develop a prioritized list of actions that protect and restore critical chum and Chinook salmon spawning habitat in the Grays River based on comprehensive geomorphic, hydrologic, and stream channel assessments; and (3) gain a better understanding of chum and Chinook salmon habitat requirements and survival within the lower Columbia River and the Grays River. The watershed-based approach to river ecosystem restoration relies on a conceptual framework that describes general relationships between natural landscape characteristics, watershed-scale habitat-forming processes, aquatic habitat conditions, and biological integrity. In addition, human land-use impacts are factored into the conceptual model because they can alter habitat quality and can disrupt natural habitat forming processes. In this model (Figure S.1), aquatic habitat--both instream and riparian--is viewed as the link between watershed conditions and biologic responses. Based on this conceptual model, assessment of habitat loss and the resultant declines in salmonid populations can be conducted by relating current and historical (e.g., natural) habitat conditions to salmonid utilization, diversity, and abundance. In addition, assessing disrupted ecosystem functions and processes within the watershed can aid in identifying the causes of habitat change and the associated decline in biological integrity. In this same way, restoration, enhancement, and conservation projects can be identified and prioritized. A watershed assessment is primarily a landscape-scale evaluation of current watershed conditions and the associated hydrogeomorphic riverine processes. The watershed assessment conducted for this project focused on watershed processes that form and maintain salmonid habitat. Landscape metrics describing the level of human alteration of natural ecosystem attributes were used as indicators of water quality, hydrology, channel geomorphology, instream habitat, and biotic integrity. Ecological (watershed) processes are related to and can be predicted based on specific aspects of spatial pattern. This study evaluated the hydrologic regime, sediment delivery regime, and riparian condition of the sub-watersheds that comprise the upper Grays River watershed relative to their natural range of conditions. Analyses relied primarily on available geographic information system (GIS) data describing landscape characteristics such as climate, vegetation type and maturity, geology and soils, topography, land use, and road density. In addition to watershed-scale landscape characteristics, the study area was also evaluated on the riparian scale, with appropriate landscape variables analyzed within

May, Christopher; Geist, David [Pacific Northwest National Laboratory

2007-04-01T23:59:59.000Z

49

A fractal set from the binary reflected Gray code  

E-Print Network [OSTI]

The permutation associated with the decimal expression of the binary reflected Gray code with $N$ bits is considered. Its cycle structure is studied. Considered as a set of points, its self-similarity is pointed out. As a fractal, it is shown to be the attractor of a IFS. For large values of $N$ the set is examined from the point of view of time series analysis

J. A. Oteo; J. Ros

2005-10-14T23:59:59.000Z

50

Self-assembly of triangular quantum dots on (111)A substrates by droplet epitaxy  

SciTech Connect (OSTI)

We report the self-assembly of triangular GaAs quantum dots (QDs) on (111)A substrates using droplet epitaxy. Shape transition from hexagonal to triangular QDs is observed with increasing crystallizing temperature. The mechanism of the morphological change is discussed in terms of different growth rates of step edges on a (111)A substrate.

Jo, M.; Mano, T.; Abbarchi, M.; Kuroda, T. [Advanced Photonics Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sakoda, K. [Advanced Photonics Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan and Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

2014-05-15T23:59:59.000Z

51

1 Dotted line for IT infrastructure and policies 2 Joint ITS/SOM appointment  

E-Print Network [OSTI]

Services Reba Brindley Project Management Transition Projects Barbara Maher Jesse Anderson Desktop to Customer Relationship Management Group 7 Dotted line to Opinder Bawa; direct reporting to home departments Phillips Teresa Regalia (3 vacant) Kevin Dale Identity Management Elliot Kendall (term) Andrei Mattes Mark

Derisi, Joseph

52

Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors  

SciTech Connect (OSTI)

A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped.

Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A. [Department of Engineering Mathematics and Physics, Faculty of Engineering, Cairo University, Giza (Egypt)

2014-02-14T23:59:59.000Z

53

Project Information Form Project Title Eco-Driving for Transit  

E-Print Network [OSTI]

Provided (by each agency or organization) DOT - $54,871.35 Total Project Cost $54,871.35 Agency IDProject Information Form Project Title Eco-Driving for Transit University Georgia Institute Project Second-by-second data for school buses, MARTA transit buses, and GRTA express buses

California at Davis, University of

54

Superconducting transition temperature in heterogeneous ferromagnet-superconductor systems  

E-Print Network [OSTI]

We study the superconducting phase transition in two systems: ferromagnet-superconductor bilayer (FSB) and a thin superconducting film with a periodic array of magnetic dots (SFMD) upon it. We show that this transition is of the first order in FSB...

Pokrovsky, Valery L.; Wei, HD.

2004-01-01T23:59:59.000Z

55

Optoelectronic devices utilizing materials having enhanced electronic transitions  

DOE Patents [OSTI]

An optoelectronic device that includes a material having enhanced electronic transitions. The electronic transitions are enhanced by mixing electronic states at an interface. The interface may be formed by a nano-well, a nano-dot, or a nano-wire.

Black, Marcie R.

2013-04-09T23:59:59.000Z

56

Optoelectronic devices utilizing materials having enhanced electronic transitions  

DOE Patents [OSTI]

An optoelectronic device that includes a material having enhanced electronic transitions. The electronic transitions are enhanced by mixing electronic states at an interface. The interface may be formed by a nano-well, a nano-dot, or a nano-wire.

Black, Marcie R. (Newton, MA)

2011-02-22T23:59:59.000Z

57

Grays Harbor Ocean Energy Company | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to:Photon Place: Golden, COIndiana JumpGray County Wind FarmOcean

58

Grays Prairie, Texas: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat Jump to:Photon Place: Golden, COIndiana JumpGray County Wind

59

A theoretical analysis of the optical absorption properties in one-dimensional InAs/GaAs quantum dot superlattices  

SciTech Connect (OSTI)

We present theoretical investigations of miniband structures and optical properties of InAs/GaAs one-dimensional quantum dot superlattices (1D-QDSLs). The calculation is based on the multi-band k·p theory, including the conduction and valence band mixing effects, the strain effect, and the piezoelectric effect; all three effects have periodic boundary conditions. We find that both the electronic and optical properties of the 1D-QDSLs show unique states which are different from those of well known single quantum dots (QDs) or quantum wires. We predict that the optical absorption spectra of the 1D-QDSLs strongly depend on the inter-dot spacing because of the inter-dot carrier coupling and changing strain states, which strongly influence the conduction and valence band potentials. The inter-miniband transitions form the absorption bands. Those absorption bands can be tuned from almost continuous (closely stacked QD case) to spike-like shape (almost isolated QD case) by changing the inter-dot spacing. The polarization of the lowest absorption peak for the 1D-QDSLs changes from being parallel to the stacking direction to being perpendicular to the stacking direction as the inter-dot spacing increases. In the case of closely stacked QDs, in-plane anisotropy, especially [110] and [11{sup ¯}0] directions also depend on the inter-dot spacing. Our findings and predictions will provide an additional degree of freedom for the design of QD-based optoelectronic devices.

Kotani, Teruhisa, E-mail: kotani.teruhisa@sharp.co.jp [Advanced Technology Research Laboratories, Sharp Corporation, 2613-1 Ichinomoto-cho, Tenri, Nara 632-8567 (Japan); Institute for Nanoelectronics, Technische Universität München, Arcisstr. 21, 80333 Munich (Germany); Birner, Stefan [Institute for Nanoelectronics, Technische Universität München, Arcisstr. 21, 80333 Munich (Germany); Walter Schottky Institute, Technische Universität München, Am Coulombwall 4, 85748 Garching (Germany); Lugli, Paolo [Institute for Nanoelectronics, Technische Universität München, Arcisstr. 21, 80333 Munich (Germany); Hamaguchi, Chihiro [Advanced Technology Research Laboratories, Sharp Corporation, 2613-1 Ichinomoto-cho, Tenri, Nara 632-8567 (Japan)

2014-04-14T23:59:59.000Z

60

Quantum Dot Light Emitting Diode  

SciTech Connect (OSTI)

The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

Keith Kahen

2008-07-31T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Quantum Dot Light Emitting Diode  

SciTech Connect (OSTI)

The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

Kahen, Keith

2008-07-31T23:59:59.000Z

62

Heat induced nanoforms of zinc oxide quantum dots and their characterization  

SciTech Connect (OSTI)

In our studies we observed heat induced phase transitions of Zinc oxide quantum dots at 60, 200, 360 and 400 Degree-Sign C, where all the transitions were irreversible except the transition at 60 Degree-Sign C which wasa reversible one. The phase transition at 60 Degree-Sign C indicated a heat induced conformational change which was supported here by studying polarizing micrographs of ZnO quantum dots thin film. The X-ray diffraction studies of the sample fired at different temperatures as indicated by the thermal analysis were performed in order to understand the changes occurred due to transitions. The study also indicated a new and simple approach to develop ZnO nanorods by just thermal decomposition of the ZnO quantum dots firing in furnace at 200 Degree-Sign C with 2h soaking. In order to have a proper insight of the structural changes we performed scanning electron microscopy. Optical characterization was done by UV-Vis and fluorescence spectrophotometer.

Dey, Anindita [Jadavpur University, Physics Department (India); Basu, Ruma [Jogamaya Devi College, Physics department (India); Das, Sukhen, E-mail: sukhendasju@gmail.com; Nandy, Papiya [Jadavpur University, Physics Department (India)

2012-02-15T23:59:59.000Z

63

Dynamics of Quantum Dot Photonic Crystal Lasers  

E-Print Network [OSTI]

Quantum dot photonic crystal membrane lasers were fabricated and the large signal modulation characteristics were studied. We find that the modulation characteristics of quantum dot lasers can be significantly improved using cavities with large spontaneous emission coupling factor. Our experiments show, and simulations confirm, that the modulation rate is limited by the rate of carrier capture into the dots to around 30GHz in our present system.

Bryan Ellis; Ilya Fushman; Dirk Englund; Bingyang Zhang; Yoshihisa Yamamoto; Jelena Vuckovic

2007-03-07T23:59:59.000Z

64

Temperature-Dependent Electron Transport in Quantum Dot Photovoltaics  

E-Print Network [OSTI]

cell efficiency milestones. Quantum dot photovoltaics is inphotovoltaics provide the potential to create high-efficiencycell efficiency milestones. Quantum dot photovoltaics is in

Padilla, Derek

2013-01-01T23:59:59.000Z

65

Temperature-Dependent Electron Transport in Quantum Dot Photovoltaics  

E-Print Network [OSTI]

4.4 Photovoltaics in Practice . . . . . . . . . . . . . .milestones. Quantum dot photovoltaics is in the bottom-rightIN QUANTUM DOT PHOTOVOLTAICS A dissertation submitted in

Padilla, Derek

2013-01-01T23:59:59.000Z

66

A `Hot Potato' Gray Code for Permutations Xi Sisi Shen 1,3  

E-Print Network [OSTI]

A `Hot Potato' Gray Code for Permutations Xi Sisi Shen 1,3 Department of Mathematics and Statistics by the chil- dren's game of Hot Potato. Our order is a transposition Gray code, meaning that consecutive) It must transpose value n (the "hot potato"); (2) It must transpose positions that are circularly adjacent

Williams, Aaron

67

All optical gray code to BCD converter e-mail : nkpark@plaza.snu.ac.kr  

E-Print Network [OSTI]

[. 1] / [ 2] / All optical gray code to BCD converter *1) , 2) , 2) , 2) , 1) 1) , 2 to binary-coded-decimal (BCD) converter for the first time in our knowledge utilizing cross gain modulations-level-simplification-method that has been used in electronics, we successfully designed the 4-bit all-optical Gray- code to BCD

Park, Namkyoo

68

Thick-shell nanocrystal quantum dots  

DOE Patents [OSTI]

Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

Hollingsworth, Jennifer A. (Los Alamos, NM); Chen, Yongfen (Eugene, OR); Klimov, Victor I. (Los Alamos, NM); Htoon, Han (Los Alamos, NM); Vela, Javier (Los Alamos, NM)

2011-05-03T23:59:59.000Z

69

Efficient all-optical production of large $^6$Li quantum gases using D$_1$ gray-molasses cooling  

E-Print Network [OSTI]

We use a gray molasses operating on the D$_1$ atomic transition to produce degenerate quantum gases of $^{6}$Li with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 10$^9$ atoms from 500 to 40 $\\mu$K in 2 ms. We observe that D$_1$ cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5$\\times$10$^{5}$ molecules and weakly-interacting degenerate Fermi gases of $7\\times$10$^{5}$ atoms at $T/T_{F}<0.1$ with a typical experimental duty cycle of 11 seconds.

A. Burchianti; G. Valtolina; J. A. Seman; E. Pace; M. De Pas; M. Inguscio; M. Zaccanti; G. Roati

2014-06-18T23:59:59.000Z

70

All-optical 4-bit Gray code to binary coded decimal converter Young Jin Jung*a  

E-Print Network [OSTI]

and Technology / Seoul, Korea, 130-791 ABSTRACT All-optical 4-bit Gray code to binary coded decimal (BCD-level simplification method and Karnaugh map method to design Gray code to BCD converter, general design concept was also founded in this research not only for the Gray code to BCD converter but also for any general

Park, Namkyoo

71

Phonon Mediated Off-Resonant Quantum Dot-Cavity Coupling  

E-Print Network [OSTI]

A theoretical model for the phonon-mediated off-resonant coupling between a quantum dot and a cavity, under resonant excitation of the quantum dot, is presented. We show that the coupling is caused by electron-phonon interaction in the quantum dot and is enhanced by the cavity. We analyze recently observed resonant quantum dot spectroscopic data by our theoretical model.

Arka Majumdar; Yiyang Gong; Erik D. Kim; Jelena Vuckovic

2010-12-14T23:59:59.000Z

72

Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells  

E-Print Network [OSTI]

to Third-Generation Photovoltaic Solar Cells A. J. Nozik,*,, M. C. Beard, J. M. Luther, M. Law,§ R. J. Applications: Quantum Dot Solar Cells 6884 6.1. Quantum Dot Solar Cell Configurations 6885 6.1.1. Photoelectrodes Composed of Quantum Dot Arrays 6885 6.1.2. Quantum Dot-Sensitized Nanocrystalline TiO2 Solar Cells

George, Steven C.

73

Wheat Gray Shorts for the Prevention of Slipped Tendons in Battery Brooder Chicks.  

E-Print Network [OSTI]

of the variations in the percentages of calcium and phosphorus studied. Rations containing 1.90-1.93 percent calcium and .87-.99 percent phosphorus, even though pro- tected by twenty and thirty percent wheat gray shorts, produced more slipped tendons than did... rations containing 1.20-1.62 per- cent cajlcium and ,5647 percent phosphorus. CONTENTS Page Introduction 5 Previous Work 5 Method of Procedure 7 Experimental Results 10 Comparison of no Wheat Gray Shorts with Twenty Percent Wheat Gray Shorts...

Sherwood, R. M. (Ross Madison); Couch, James Russell

1936-01-01T23:59:59.000Z

74

Photodetectors based on colloidal quantum dots  

E-Print Network [OSTI]

Inspired by recent work demonstrating photocurrent enhancement in quantum-dot (QD) solids via post-deposition chemical annealing and by recent successes incorporating single monolayers of QDs in light-emitting devices ...

Oertel, David C. (David Charles)

2007-01-01T23:59:59.000Z

75

Synthesis and characterization of infrared quantum dots  

E-Print Network [OSTI]

This thesis focuses on the development of synthetic methods to create application ready quantum dots (QDs) in the infrared for biological imaging and optoelectronic devices. I concentrated primarily on controlling the size ...

Harris, Daniel Kelly

2014-01-01T23:59:59.000Z

76

Mn/DOT County Road Safety Plans  

E-Print Network [OSTI]

Roads Program !! Minnesota Central Safety Funds !! Foster safety culture among county stakeholders 41 Mn/DOT County Road Safety Plans CTS Annual Research Conference April 27 & 28, 2010 Howard Preston & Objectives !! Project Overview !! Schedule, Participating Counties, Approach !! Safety Emphasis Areas

Minnesota, University of

77

DRAFT Lower Columbia Salmon and Steelhead Recovery Plan GRAYS II, 3-1 May 2004  

E-Print Network [OSTI]

. Approximately 95% of the Grays Subbasin is forested and commercial timber companies own 73% of the land. State ownership comprises the bulk of the remaining lands. Much of the basin has been impacted by timber harvest

78

Anthropogenic Disturbance of Western Gray Whale Behavior Off Sakhalin Island, Russia  

E-Print Network [OSTI]

, the western gray whale population face several threats to their future survival. On their only known feeding grounds off the northeastern coast of Sakhalin Island, Russia, anthropogenic activity has increased in the past decade due to oil and gas exploration...

Gailey, Glenn Andrew

2013-05-14T23:59:59.000Z

79

An environmental impact assessment of quantum dot photovoltaics (QDPV) from raw material acquisition through use  

E-Print Network [OSTI]

An environmental impact assessment of quantum dot photovoltaics (QDPV) from raw material: Life cycle assessment Quantum dots Nanophotovoltaics Quantum dot photovoltaic modules Solar energy Assessment (LCA) of a proposed type of nanophotovoltaic, quantum dot photovoltaic (QDPV) module. The LCA

Illinois at Chicago, University of

80

InAs/GaAs p-type quantum dot infrared photodetector with higher efficiency  

SciTech Connect (OSTI)

An InAs/GaAs quantum dot infrared photodetector (QDIP) based on p-type valence-band intersublevel hole transitions as opposed to conventional electron transitions is reported. Two response bands observed at 1.5–3 and 3–10??m are due to transitions from the heavy-hole to spin-orbit split-off QD level and from the heavy-hole to heavy-hole level, respectively. Without employing optimized structures (e.g., the dark current blocking layer), the demonstrated QDIP displays promising characteristics, including a specific detectivity of 1.8×10{sup 9} cm·Hz{sup 1/2}/W and a quantum efficiency of 17%, which is about 5% higher than that of present n-type QDIPs. This study shows the promise of utilizing hole transitions for developing QDIPs.

Lao, Yan-Feng; Wolde, Seyoum; Unil Perera, A. G., E-mail: uperera@gsu.edu [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States); Zhang, Y. H.; Wang, T. M.; Liu, H. C. [Key Laboratory of Artificial Structures and Quantum Control, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory of Artificial Structures and Quantum Control, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Kim, J. O.; Schuler-Sandy, Ted; Tian, Zhao-Bing; Krishna, S. S. [Center for High Technology Materials, Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87106 (United States)] [Center for High Technology Materials, Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87106 (United States)

2013-12-09T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Fluorescence relaxation dynamics of CdSe and CdSe/CdS core/shell quantum dots  

SciTech Connect (OSTI)

Time-resolved fluorescence spectra for colloidal CdSe and CdSe/CdS core/shell quantum dots have been investigated to know their electron relaxation dynamics at the maximum steady state fluorescence intensity. CdSe core and CdSe/CdS type I core-shell materials with different shell (CdS) thicknesses have been synthesized using mercaptoacetic acid as a capping agent. Steady state absorption and emission studies confirmed successful synthesis of CdSe and CdSe/CdS core-shell quantum dots. The fluorescence shows a tri-exponential decay with lifetimes 57.39, 7.82 and 0.96 ns for CdSe quantum dots. The lifetime of each recombination decreased with growth of CdS shell over the CdSe core, with maximum contribution to fluorescence by the fastest transition.

Kaur, Gurvir; Kaur, Harmandeep [Centre of Advanced Study in Physics, Department of Physics, Panjab University, Chandigarh-160014 (India); Tripathi, S. K., E-mail: surya@pu.ac.in [Centre of Advanced Study in Physics, Panjab University, Chandigarh- 160014 (India)

2014-04-24T23:59:59.000Z

82

Polarization-entangled photon generation by a semiconductor quantum dot coupled to a cavity interacting with external fields  

E-Print Network [OSTI]

We theoretically investigate polarization-entangled photon generation by using a semiconductor quantum dot embedded in a microcavity. The entangled states can be produced by the application of two cross-circularly polarized laser fields. The quantum dot nanostructure is considered as a four-level system (ground, two excitons and bi-exciton states) and the theoretical study relies on the dressed states scheme. The quantum correlations, reported in terms of the entanglement of formation, are extensively studied for several values of the important parameters of the quantum dot system as the bi-exciton binding energy, {the decoherence times of the characteristic transitions, the quality factor of the cavity} and the intensities of the applied fields.

Kostas Blekos; Nikos Iliopoulos; Maria-Eftaksia Stasinou; Evaggelos Vlachos; Andreas F. Terzis

2014-04-07T23:59:59.000Z

83

Nanostructured architectures for colloidal quantum dot solar cells  

E-Print Network [OSTI]

This thesis introduces a novel ordered bulk heterojunction architecture for colloidal quantum dot (QD) solar cells. Quantum dots are solution-processed nanocrystals whose tunable bandgap energies make them a promising ...

Jean, Joel, S.M. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

84

Fast quantum dot single photon source triggered at telecommunications wavelength  

E-Print Network [OSTI]

We demonstrate a quantum dot single photon source at 900 nm triggered at 300 MHz by a continuous wave telecommunications wavelength laser followed by an electro-optic modulator. The quantum dot is excited by on-chip-generated second harmonic radiation, resonantly enhanced by a GaAs photonic crystal cavity surrounding the InAs quantum dot. Our result suggests a path toward the realization of telecommunications-wavelength-compatible quantum dot single photon sources with speeds exceeding 1 GHz.

Kelley Rivoire; Sonia Buckley; Arka Majumdar; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

2010-12-20T23:59:59.000Z

85

Coherent Optical Spectroscopy of a Single Quantum Dot Via an Off-Resonant Cavity  

E-Print Network [OSTI]

In recent experiments on coupled quantum dot (QD) optical cavity systems a pronounced interaction between the dot and the cavity has been observed even for detunings of many cavity linewidths. This interaction has been attributed to an incoherent phonon-mediated scattering process and is absent in atomic systems. Here, we demonstrate that despite its incoherent nature, this process preserves the signatures of coherent interaction between a QD and a strong driving laser, which may be observed via the optical emission from the off-resonant cavity. Under bichromatic driving of the QD, the cavity emission exhibits spectral features consistent with optical dressing of the QD transition. In addition to revealing new aspects of the off-resonant QD-cavity interaction, this result provides a new, simpler means of coherently probing QDs than traditional approaches and opens the possibility of employing off-resonant cavities to optically interface QD-nodes in quantum networks.

Arka Majumda; Alexander Papageorge; Erik D. Kim; Michal Bajscy; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

2011-03-14T23:59:59.000Z

86

A hybrid double-dot in silicon  

SciTech Connect (OSTI)

We report electrical measurements of a single arsenic dopant atom in the tunnel barrier of a silicon single-electron transistor (SET). In addition to performing the electrical characterisation of the individual dopants, we study the series electrical transport through the dopant and SET. We measure the bias triangles of this hybrid double-dot and show that we can tune the electrostatic coupling between the two sub-systems. Additionally, we measured SET in which an additional plunger gate allows the reduction of the electron number in the SET down to the few-electron regime where the dot presents well-defined spin configurations. Finally, we discuss the challenges of operating a dopant-dot hybrid system in the few-electron regime.

Gonzalez-Zalba, M. F.; Heiss, D.; Ferguson, A. J. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge (United Kingdom)

2013-12-04T23:59:59.000Z

87

Engineered Quantum Dot Single Photon Sources  

E-Print Network [OSTI]

Fast, high efficiency, and low error single photon sources are required for implementation of a number of quantum information processing applications. The fastest triggered single photon sources to date have been demonstrated using epitaxially grown semiconductor quantum dots (QDs), which can be conveniently integrated with optical microcavities. Recent advances in QD technology, including demonstrations of high temperature and telecommunications wavelength single photon emission, have made QD single photon sources more practical. Here we discuss the applications of single photon sources and their various requirements, before reviewing the progress made on a quantum dot platform in meeting these requirements.

Sonia Buckley; Kelley Rivoire; Jelena Vuckovic

2012-10-03T23:59:59.000Z

88

Bilayer graphene quantum dot defined by topgates  

SciTech Connect (OSTI)

We investigate the application of nanoscale topgates on exfoliated bilayer graphene to define quantum dot devices. At temperatures below 500 mK, the conductance underneath the grounded gates is suppressed, which we attribute to nearest neighbour hopping and strain-induced piezoelectric fields. The gate-layout can thus be used to define resistive regions by tuning into the corresponding temperature range. We use this method to define a quantum dot structure in bilayer graphene showing Coulomb blockade oscillations consistent with the gate layout.

Müller, André; Kaestner, Bernd; Hohls, Frank; Weimann, Thomas; Pierz, Klaus; Schumacher, Hans W., E-mail: hans.w.schumacher@ptb.de [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

2014-06-21T23:59:59.000Z

89

Fracture toughness studies of gray and ductile cast irons using a J-integral approach  

E-Print Network [OSTI]

it to flow into the area where the crack has propagated. 4. The specimen is broken open and then the aa is measured using a ruler, a magnifying 33 Pr~ Surface Figure 13. Scheamtic of a gray cast iron specimen which has been fatigue precracked, pulled... to the difficulty in determining the frac- tuze toughness of gray iron. As the specimen is pulled, the flakes open up; and nucleate small miczocracks which appear to coalesce with very little local plastic flow giving a very low tough- ness to the material...

Floyd, Donna Lynne Woodall

1981-01-01T23:59:59.000Z

90

Synthesis of CdSe quantum dots for quantum dot sensitized solar cell  

SciTech Connect (OSTI)

CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5.

Singh, Neetu, E-mail: singh.neetu1985@gmail.com; Kapoor, Avinashi [Department of Electronic Science, University of Delhi South Campus, New Delhi-110 021 (India); Kumar, Vinod [Department of Physics, University of the Free State, Bloemfontein, ZA9300 (South Africa); Mehra, R. M. [School of Engineering and Technology, Sharda University, Greater Noida-201 306, U.P. (India)

2014-04-24T23:59:59.000Z

91

Enhanced Joule Heating in Umbral Dots  

E-Print Network [OSTI]

We present a study of magnetic profiles of umbral dots (UDs) and its consequences on the Joule heating mechanisms. Hamedivafa (2003) studied Joule heating using vertical component of magnetic field. In this paper UDs magnetic profile has been investigated including the new azimuthal component of magnetic field which might explain the relatively larger enhancement of Joule heating causing more brightness near circumference of UD.

Chandan Joshi; Lokesh Bharti; S. N. A. Jaaffrey

2007-05-08T23:59:59.000Z

92

Mn/DOT's Project Peer Review  

E-Print Network [OSTI]

and sustain this culture #12;Project Management #12;Recent National Work in Transportation Project ManagementMn/DOT's Project Management Peer Review Creating a Project Management Culture 2010 CTS Research a Peer Review? Why Project Management? ·Improve project delivery performance ­ on time, on budget (an

Minnesota, University of

93

Spin dynamics characterization in magnetic dots  

E-Print Network [OSTI]

J= 0.1 meV Frequency (JS) SDF J=0.6 meV Fig. 2. (Colorfrom diagonalization (SDF: J=1 eV) Frequency spectrum fromMagnon DOS for a circular dot SDF: J=0.6 meV N=1600 N=400 N=

Mozaffari, Mohammad Reza; Esfarjani, Keivan

2007-01-01T23:59:59.000Z

94

Pulsed-gate measurements of the singlet-triplet relaxation time in a two-electron double quantum dot  

E-Print Network [OSTI]

-gate technique with charge sensing is used to measure the singlet-triplet relaxation time for nearly degenerate spin states in a two-electron double quantum dot. Transitions from the 1,1 charge occupancy state. At dilution refrigerator temperatures, this implies that EZeeman kBT 10 eV, or B 0.5 T. For B 0.5 T, T1 shows

Petta, Jason

95

Reply: Lithium and Increased Cortical Gray Matter--More Tissue or More Water?  

E-Print Network [OSTI]

Reply: Lithium and Increased Cortical Gray Matter--More Tissue or More Water? To the Editor: W e cortices, in lithium-treated patients with bipolar disorder, relative to healthy control subjects (1). Dr patients. Although lithium's effects on body water homeostasis (2) are important to consider, the absence

Thompson, Paul

96

A new airfuel WSGGM (weighted sum of gray gas model) for better utility  

E-Print Network [OSTI]

1 A new airfuel WSGGM (weighted sum of gray gas model) for better utility boiler simulation properties. · For each condition: use the validated EWBM to generate emissivity database, spanning a larger). Large emissivity database matrix: 146 discrete values for PL times 101 data points for Tg. · For each

Yin, Chungen

97

Project Plan Field Assessment of the Effectiveness of DiazaConTM on Reducing Gray  

E-Print Network [OSTI]

Project Plan Field Assessment of the Effectiveness of DiazaConTM on Reducing Gray Squirrel that the contraceptive was effective in preventing reproduction in both male and female squirrels. However, the cost of capturing and vaccinating individual EGS with GonaConTM was $15/squirrel and proved to be cost prohibitive

Bolding, M. Chad

98

Stable spheromak formation by merging in an oblate flux conserver T. Gray,1,a  

E-Print Network [OSTI]

Stable spheromak formation by merging in an oblate flux conserver T. Gray,1,a M. R. Brown,1 C. D; accepted 4 February 2010; published online 29 March 2010 An axisymmetric spheromak formed by the dynamic merging of two smaller spheromaks of the same magnetic helicity in the Swarthmore Spheromak Experiment SSX

Brown, Michael R.

99

COGNITIVE METRICS PROFILING Wayne D. Gray, Michael J. Schoelles, & Chris Sims  

E-Print Network [OSTI]

COGNITIVE METRICS PROFILING Wayne D. Gray, Michael J. Schoelles, & Chris Sims Cognitive Science Department Rensselaer Polytechnic Institute [grayw; schoem, simsc] @rpi.edu Cognitive Metrics Profiling promises a new approach to minimizing the cognitive workload of interactive systems. By metering high

Gray, Wayne

100

Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu  

E-Print Network [OSTI]

Modeling a Continuous Dynamic Task Wayne D. Gray, Michael J. Schoelles, & Wai-Tat Fu Human Factors in several ways. Modeling the impact of one such difference raised theoretical issues in motor movement and attention. For motor movement, the issue concerned the functional shape and size of a target

Gray, Wayne

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

The gray snapper, Lutjanus griseus, is a moderate-size (to 8 kg) snapper  

E-Print Network [OSTI]

- sachusetts (Sumner et al., 1911), and transforming gray snapper larvae have been caught in ichthyoplankton samples or gear types. Croker (1962), Starck and Schroeder (1970), and Rutherford et al. (1983) conducted between 1986 and 1997.Average annual landings from the south Florida area (Ft. Pierce through the Dry

102

Management of Wetlands for Wildlife Matthew J. Gray, Heath M. Hagy, J. Andrew Nyman,  

E-Print Network [OSTI]

Chapter 4 Management of Wetlands for Wildlife Matthew J. Gray, Heath M. Hagy, J. Andrew Nyman, and Joshua D. Stafford Abstract Wetlands are highly productive ecosystems that provide habitat for a diversity of wildlife species and afford various ecosystem services. Managing wetlands effectively requires

Wang, Xiaorui "Ray"

103

Wetlands Ecology and Management Instructor: Dr. Matthew Gray (mgray11@utk.edu)  

E-Print Network [OSTI]

WFS 340 Wetlands Ecology and Management Fall 2010 Instructor: Dr. Matthew Gray (mgray11@utk://fwf.ag.utk.edu/mgray/wfs340/340home.htm Recommended Text: Wetlands, 2007, 4th edition (ISBN 978-0-471-69967-5) or Wetlands: To expose students to the basic principles of wetland ecology and management via class lectures, labs

Gray, Matthew

104

Wetlands Ecology and Management Instructor: Dr. Matthew Gray (mgray11@utk.edu)  

E-Print Network [OSTI]

WFS 340 Wetlands Ecology and Management Fall 2011 Instructor: Dr. Matthew Gray (mgray11@utk://fwf.ag.utk.edu/mgray/wfs340/340home.htm Recommended Text: Wetlands, 2007, 4th edition (ISBN 978-0-471-69967-5) or Wetlands: To expose students to the basic principles of wetland ecology and management via class lectures, labs

Gray, Matthew

105

Wetlands Ecology and Management Instructor: Dr. Matthew Gray (mgray11@utk.edu)  

E-Print Network [OSTI]

WFS 340 Wetlands Ecology and Management Fall 2012 Instructor: Dr. Matthew Gray (mgray11@utk://fwf.ag.utk.edu/mgray/wfs340/340home.htm Required Text: Wetland Restoration and Construction, 2011 (978-0-9834558-0-6) Author: Thomas Biebighauser Recommended Text: Wetlands, 2007, 4th edition (ISBN 978-0-471-69967-5) or Wetlands

Gray, Matthew

106

Spectral dependence of the linewidth enhancement factor in quantum dot lasers  

SciTech Connect (OSTI)

The spectral analysis of amplified spontaneous emission is used to determine the linewidth enhancement factor (?-factor) in lasers based on InAs/InGaAs quantum dots (QDs) in a wide spectral range near the ground-state optical transition energy. The effect of the pump current and number of QDs on the spectral dependences of the ?-factor is examined. The temperature dependence of the spectra of the ?-factor is experimentally determined for the first time for lasers with InAs/InGaAs QDs. An explanation is suggested for the observed anomalous decrease in the ?-factor with increasing temperature.

Zubov, F. I., E-mail: fedyazu@mail.ru [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Shernyakov, Yu. M.; Maximov, M. V. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Zhukov, A. E. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Livshits, D. A. [Innolume GmbH (Germany); Payusov, A. S.; Nadtochiy, A. M. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Savelyev, A. V.; Kryzhanovskaya, N. V. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Gordeev, N. Yu. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-12-15T23:59:59.000Z

107

Intersublevel dephasing in InAs/GaAs quantum dots below the Reststrahlen band  

SciTech Connect (OSTI)

Using transient four-wave mixing in the terahertz range, we have measured the s-p inter-sublevel dephasing time in self-assembled InAs/GaAs quantum dots for transition energies below the Reststrahlen band. Dephasing times of up to 600?ps at a photon energy of 18?meV have been determined. By comparing pump-probe and four-wave mixing measurements, we show that there is no significant influence of any pure dephasing process at low temperature. The linear temperature dependence is consistent with acoustic phonon scattering.

Teich, M., E-mail: m.teich@hzdr.de; Stephan, D. R.; Helm, M. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany) [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Winnerl, S.; Schneider, H. [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany)] [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); Wilson, L. R. [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)] [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)

2013-12-16T23:59:59.000Z

108

Fabrication and characterization of p-channel Si double quantum dots  

SciTech Connect (OSTI)

Lithographically defined p-channel Si single hole transistors (SHTs) and double quantum dot (DQD) devices are fabricated and characterized. Coulomb oscillations are clearly evident at a temperature of 4.2?K. The charging energy and the diameter of the SHT are estimated from the Coulomb diamonds. Honeycomb-like charge stability diagrams are observed from measurements of the DQD devices. Single hole transitions through the DQD are detected using an integrated SHT as a charge sensor, and a few-hole regime of the DQD is observed.

Yamada, Ko; Kambara, Tomohiro; Oda, Shunri [Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Kodera, Tetsuo, E-mail: kodera.t.ac@m.titech.ac.jp [Department of Physical Electronics, Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan)

2014-09-15T23:59:59.000Z

109

Strain-induced vertical self-organization of semiconductor quantum dots: A computational study  

SciTech Connect (OSTI)

Atomistic strain simulations based on the valence force field method are employed to study the vertical arrangements of semiconductor quantum dot (QD) multilayers. The effects of the QD shape, dimensions, and materials parameters are systematically investigated, varying independently the following parameters: spacer width H, QD lateral spacing D, base b, and height h, slope of the side facets, elastic properties of the dot and the substrate materials, and lattice mismatch between the dot and the substrate. The transition between vertically aligned and anti-aligned structures is found to be determined mainly by the ratios H/D and b/D, as well as by the strain anisotropy of the substrate and to a lesser extent of the QD. The dependence on the QD height h is significant only for steep side facets and large aspect ratios h/b, and the effects of the lattice mismatch strain and the bulk elastic moduli are found to be negligible. The comparison with experimental data shows an excellent agreement with the results from the simulations, demonstrating that the presented analysis results in precise theoretical predictions for the vertical self-organization regime in a wide range of QD materials systems.

Shtinkov, N., E-mail: nshtinkov@uottawa.ca [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa (Ontario) K1N 6N5 (Canada)

2013-12-28T23:59:59.000Z

110

Controlling quantum dot energies using submonolayer bandstructure engineering  

SciTech Connect (OSTI)

We demonstrate control of energy states in epitaxially-grown quantum dot structures formed by stacked submonolayer InAs depositions via engineering of the internal bandstructure of the dots. Transmission electron microscopy of the stacked sub-monolayer regions shows compositional inhomogeneity, indicative of the presence of quantum dots. The quantum dot ground state is manipulated not only by the number of deposited InAs layers, but also by control of the thickness and material composition of the spacing layers between submonolayer InAs depositions. In this manner, we demonstrate the ability to shift the quantum dot ground state energy at 77?K from 1.38?eV to 1.88?eV. The results presented offer a potential avenue towards enhanced control of dot energies for a variety of optoelectronic applications.

Yu, L.; Law, S.; Wasserman, D. [Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, Urbana, Illinois 61801 (United States); Jung, D.; Lee, M. L. [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States); Shen, J.; Cha, J. J. [Department of Mechanical Engineering and Materials Science and Energy Science Institute, Yale University, New Haven, Connecticut 06520 (United States)

2014-08-25T23:59:59.000Z

111

Establishment of correlated states in a quantum dot interacting with an acoustic phonon reservoir  

E-Print Network [OSTI]

We investigate the effects of a low frequency (acoustic) phonon bath on the dynamics of a quantum dot modelled as a cascade three-level system. We show that the phonon bath appears to the upper transition of the cascade system as a broadband reservoir of inverted rather than conventional harmonic oscillators. The action of the annihilation and creation operators of the inverted oscillator are interchanges relative to those of the usual harmonic oscillator that it serves as a linear amplifier to the system, and thereby gives rise to unusual features in the dynamics of the quantum dot. We find that the phonon bath, although being in a thermal state, affects the quantum dot as a correlated-type reservoir which results in the decay of the system to a correlated two-photon state with the population distribution no longer obeying a Boltzmann distribution. It is particularly interesting that even for a zero temperature phonon reservoir the steady state is a correlated state which under appropriate conditions on the Rabi frequencies and the damping rates can reduce to a strongly correlated pure state. It is shown that the two-photon correlations result in a significant squeezing and strong two-photon correlations in the radiation field emitted by the quantum dot. The presence of the correlations in the system is manifest in the presence of quantum beats in the time evolution of the populations and the radiation intensity. The effect of the ordinary spontaneous emission on the features induced by the phonon bath is also discussed.

Hui Huang; Gao-xiang Li; Wen-ju Gu; Zbigniew Ficek

2014-08-20T23:59:59.000Z

112

Elastic fields of quantum dots in subsurface layers A. E. Romanov  

E-Print Network [OSTI]

to vertical stacking of dots provided that the thickness of the intervening layer ``spacer layer'' is in the order or thinner than the lateral dimensions of the dot.4 It is now clear that dot ordering is driven

Beltz, Glenn E.

113

Deposition of colloidal quantum dots by microcontact printing for LED display technology  

E-Print Network [OSTI]

This thesis demonstrates a new deposition method of colloidal quantum dots within a quantum dot organic light-emitting diode (QD-LED). A monolayer of quantum dots is microcontact printed as small as 20 ,Lm lines as well ...

Kim, LeeAnn

2006-01-01T23:59:59.000Z

114

Separability and dynamical symmetry of Quantum Dots  

SciTech Connect (OSTI)

The separability and Runge–Lenz-type dynamical symmetry of the internal dynamics of certain two-electron Quantum Dots, found by Simonovi? et al. (2003), are traced back to that of the perturbed Kepler problem. A large class of axially symmetric perturbing potentials which allow for separation in parabolic coordinates can easily be found. Apart from the 2:1 anisotropic harmonic trapping potential considered in Simonovi? and Nazmitdinov (2013), they include a constant electric field parallel to the magnetic field (Stark effect), the ring-shaped Hartmann potential, etc. The harmonic case is studied in detail. -- Highlights: • The separability of Quantum Dots is derived from that of the perturbed Kepler problem. • Harmonic perturbation with 2:1 anisotropy is separable in parabolic coordinates. • The system has a conserved Runge–Lenz type quantity.

Zhang, P.-M., E-mail: zhpm@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Zou, L.-P., E-mail: zoulp@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Horvathy, P.A., E-mail: horvathy@lmpt.univ-tours.fr [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Laboratoire de Mathématiques et de Physique Théorique, Tours University (France); Gibbons, G.W., E-mail: G.W.Gibbons@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, Cambridge University, Cambridge (United Kingdom)

2014-02-15T23:59:59.000Z

115

Local Quantum Dot Tuning on Photonic Crystal Chips  

E-Print Network [OSTI]

Quantum networks based on InGaAs quantum dots embedded in photonic crystal devices rely on QDs being in resonance with each other and with the cavities they are embedded in. We developed a new technique based on temperature tuning to spectrally align different quantum dots located on the same chip. The technique allows for up to 1.8nm reversible on-chip quantum dot tuning.

Andrei Faraon; Dirk Englund; Ilya Fushman; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

2007-03-28T23:59:59.000Z

116

How Analysts Cognitively “Connect the Dots  

SciTech Connect (OSTI)

As analysts attempt to make sense of a collection of documents, such as intelligence analysis reports, they may wish to “connect the dots” between pieces of information that may initially seem unrelated. This process of synthesizing information between information requires users to make connections between pairs of documents, creating a conceptual story. We conducted a user study to analyze the process by which users connect pairs of documents and how they spatially arrange information. Users created conceptual stories that connected the dots using organizational strategies that ranged in complexity. We propose taxonomies for cognitive connections and physical structures used when trying to “connect the dots” between two documents. We compared the user-created stories with a data-mining algorithm that constructs chains of documents using co-occurrence metrics. Using the insight gained into the storytelling process, we offer design considerations for the existing data mining algorithm and corresponding tools to combine the power of data mining and the complex cognitive processing of analysts.

Bradel, Lauren; Self, Jessica S.; Endert, Alexander; Hossain, Shahriar M.; North, Chris; Ramakrishnan, Naren

2013-06-04T23:59:59.000Z

117

Solution-Processed Solar Cells using Colloidal Quantum Dots ...  

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

physical understanding, and performance-oriented engineering of colloidal quantum dot solar cells and light sensors. Bio: Ted Sargent received the B.Sc.Eng. (Engineering...

118

Microfluidic self-assembly of quantum dot compound micelles.  

E-Print Network [OSTI]

??This thesis is devoted to the development of microfluidic processes for the controlled self-assembly of quantum dot compound micelles (QDCMs). Microfluidic processes are developed to… (more)

Schabas, Greg

2007-01-01T23:59:59.000Z

119

Quantum Dot Tracers for Use in Engineered Geothermal  

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

tracers, colloidal quantum dots, that offer great promise for use in characterizing fracture networks in EGS reservoirs. Since the wavelength of fluorescence (color) of these...

120

Quantum Dot Tracers for Use in Engineered Geothermal Systems...  

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

nanoparticles(quantum dots)that offer great promise for use in characterizing fracture networks in EGS reservoirs. tracersrosequantumdot.pdf More Documents &...

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

assembled quantum dots: Topics by E-print Network  

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

Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells Biology and Medicine Websites Summary: to Third-Generation...

122

asymmetry quantum dots: Topics by E-print Network  

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

Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells Biology and Medicine Websites Summary: to Third-Generation...

123

Temperature-Dependent Electron Transport in Quantum Dot Photovoltaics.  

E-Print Network [OSTI]

??Quantum dot photovoltaics have attracted much interest from researchers in recent years. They have the potential to address both costs and efficiencies of solar cells… (more)

Padilla, Derek

2013-01-01T23:59:59.000Z

124

E-Print Network 3.0 - atom quantum dot Sample Search Results  

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

third-generation solar cell efficiencies. Tiny quantum dots... the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable... quantum...

125

Enhanced performance of quantum dot solar cells based on type II quantum dots  

SciTech Connect (OSTI)

The characteristics of quantum dot solar cells (QDSCs) based on type II QDs are investigated theoretically. Based on a drift-diffusion model, we obtained a much higher open circuit voltage (V{sub oc}) as well as conversion efficiency in a type II QDSC, compared to type I QDSCs. The improved V{sub oc} and efficiency are mainly attributed to the much longer Auger recombination lifetime in type II QDs. Moreover, the influence of the carrier lifetime on devices' performance is discussed and clarified. In addition, an explicit criterion to determine the role of quantum dots in solar cells is put forward.

Xu, Feng; Yang, Xiao-Guang; Luo, Shuai; Lv, Zun-Ren; Yang, Tao, E-mail: tyang@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

2014-10-07T23:59:59.000Z

126

Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation  

SciTech Connect (OSTI)

Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this effect produces greatly enhanced theoretical thermodynamic conversion efficiencies that range from 45-85%, depending upon solar concentration, the cell temperature, and the number of electron-hole pairs produced per photon. For quantum dots (QDs), electron-hole pairs exist as excitons. We have observed astoundingly efficient multiple exciton generation (MEG) in QDs of PbSe (bulk Eg = 0.28 eV), ranging in diameter from 3.9 to 5.7nm (Eg = 0.73, 0.82, and 0.91 eV, respectively). The effective masses of electron and holes are about equal in PbSe, and the onset for efficient MEG occurs at about three times the QD HOMO-LUMO transition (its ''bandgap''). The quantum yield rises quickly after the onset and reaches 300% at 4 x Eg (3.64 eV) for the smallest QD; this means that every QD in the sample produces three electron-hole pairs/photon.

Hanna, M. C.; Ellingson, R. J.; Beard, M.; Yu, P.; Micic, O. I.; Nozik, A. J.; c.

2005-01-01T23:59:59.000Z

127

Quantum-dot all-optical logic in a structured vacuum  

SciTech Connect (OSTI)

We demonstrate multiwavelength channel optical logic operations on the Bloch vector of a quantum two-level system in the structured electromagnetic vacuum of a bimodal photonic crystal waveguide. This arises through a bichromatic strong-coupling effect that enables unprecedented control over single quantum-dot (QD) excitation through two beams of ultrashort femtojoule pulses. The second driving pulse (signal) with slightly different frequency and weaker strength than the first (holding) pulse leads to controllable strong modulation of the QD Bloch vector evolution path. This occurs through resonant coupling of the signal pulse with the Mollow sideband transitions created by the holding pulse. The movement of the Mollow sidebands during the passage of the holding pulse leads to an effective chirping in transition frequency seen by the signal. Bloch vector dynamics in the rotating frame of the signal pulse and within the dressed-state basis created by the holding pulse reveals that this chirped coupling between the signal pulse and the Mollow sidebands leads to either augmentation or negation of the final quantum-dot population (after pulse passage) compared to the outcome of the holding pulse alone and depending on the relative frequencies of the pulses. By making use of this extra degree of freedom for ultrafast control of QD excitations, applications in ultrafast all-optical logic and, or, and not gates are proposed in the presence of significant (0.1) THz nonradiative dephasing and (about 1%) inhomogeneous broadening.

Ma Xun; John, Sajeev [Department of Physics, University of Toronto, Toronto, M5S 1A7 (Canada)

2011-07-15T23:59:59.000Z

128

The 21st LH Gray Conference (June 4-6, 2008)  

SciTech Connect (OSTI)

The 21st LH Gray Conference, organised by the LH Gray Trust with the Society for Radiological Protection, brought together international experts in radiobiology, epidemiology and risk assessment, and scientists involved in diagnostic and therapeutic radiation exposure. The meeting - held in Edinburgh, Scotland 4?6 June 2008 - aimed to raise awareness, educate and share knowledge of important issues in radiation protection. A distinguished group of speakers discussed topics which included: non-targeted effects of radiation, exposure to high natural background radiation, non-cancer effects in Japanese bomb survivors, lessons learnt from Chernobyl, radiation in the workplace, biokinetic modelling, uncertainties in risk estimation, issues in diagnostic medical exposures, lessons leant from the polonium-210 incidence and how the radiobiology-radiation oncology community is needed to help society prepare for potential future acts of radiation terrorism. The conference highlighted the importance, relevance and topicality of radiobiology today.

West, C.M.L.; Martin, C.J.; Sutton, D.G.; Wright, E.G.

2009-01-12T23:59:59.000Z

129

Quasi-bound states and continuum absorption background of polar Al{sub 0.5}Ga{sub 0.5}N/GaN quantum dots  

SciTech Connect (OSTI)

A theoretical interpretation of the photoluminescence excitation spectra of self-organized polar GaN/(Al,Ga)N quantum dots is presented. A numerical method assuming a realistic shape of the dots and including the built-in electric field effects is developed to calculate their energy structure and hence their optical absorption. The electron and hole spectra show the existence of a set of quasi-bound states that does not originate from the wetting layer and plays a crucial role in the observed absorption spectrum of the GaN/(Al,Ga)N dots. Transitions involving these quasi-bound states and wetting layer states give a sufficient explanation for the observed continuum absorption background. The properties of this absorption band, especially its extension, depend strongly on the dot's size. Our simulation provides a natural explanation of the experimental luminescence excitation spectra of ensembles of dots of different heights. Our theoretical model can be convenient for future optical studies including systems with more complicated potentials.

Elmaghraoui, D., E-mail: elmaghraouidonia@yahoo.fr; Triki, M. [Laboratoire de physique de la matière condensé, Faculté des sciences de Tunis, Campus universitaire 2092 El Manar (Tunisia); Jaziri, S. [Laboratoire de physique de la matière condensé, Faculté des sciences de Tunis, Campus universitaire 2092 El Manar (Tunisia); Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte 7021 Jarzouna (Tunisia); Leroux, M.; Brault, J. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Rue B. Gregory, 06560 Valbonne (France)

2014-07-07T23:59:59.000Z

130

Measurement of the body composition of living gray seals by hydrogen isotope dilution  

SciTech Connect (OSTI)

The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by {sup 2}H or {sup 3}H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both {sup 2}HHO and {sup 3}HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with {sup 3}H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida) and from the equation of Pace and Rathbun, which has been reported to be generally applicable to mammals.

Reilly, J.J.; Fedak, M.A. (Natural Environment Research Council, High Cross, Cambridge (England))

1990-09-01T23:59:59.000Z

131

Minnesota Guidestar www.dot.state.mn.us/guidestar  

E-Print Network [OSTI]

.dot.state.mn.us/guidestar What is ITS? · Application of technology to improve the safety and efficiency of the transportation system. #12;Minnesota Guidestar www.dot.state.mn.us/guidestar What is ITS? · Traffic Management ­ Signal Systems ­ Ramp Meters · Emergency Response ­ Mobile Data Terminals ­ 911 Dispatch ­ RF Data Networks

Minnesota, University of

132

State DOT: PENNSYLVANIA State Report Questions on NDT Testing  

E-Print Network [OSTI]

capacity surveys, management of load restrictions, fatigue tests and compaction control. On concreteState DOT: PENNSYLVANIA State Report Questions on NDT Testing 1. What NDT testing methods for concrete materials, concrete pavements, and overlays are you trying? PennDOT performs Falling Weight

133

State DOT: Missouri State Report Questions on NDT Testing  

E-Print Network [OSTI]

State DOT: Missouri State Report Questions on NDT Testing 1. What NDT testing methods for concrete maturity meter MoDOT has utilized the rebound hammer to evaluate in-place concrete when cylinder testing materials, concrete pavements, and overlays are you trying? a) Maturity Method b) Rebound Hammer c) Cover

134

Project Information Form Project Title Strategies for Transitioning to Zero-Emission Vehicles--Freight  

E-Print Network [OSTI]

Source(s) and Amounts Provided (by each agency or organization) US DOT $38,884 Total Project Cost $38Project Information Form Project Title Strategies for Transitioning to Zero-Emission Vehicles Description of Research Project According to the EIA, freight modes accounted for 29% of transportation fuel

California at Davis, University of

135

Project Information Form Project Title Innovative Data Collection to Improve Transit Service Assessment  

E-Print Network [OSTI]

(s) and Amounts Provided (by each agency or organization) DOT - $102,971.57 Total Project Cost $102,971.57 AgencyProject Information Form Project Title Innovative Data Collection to Improve Transit Service of Research Project Mobile information technology will be used to compare travel behavior of populations

California at Davis, University of

136

Project Information Form Project Title White Paper on Strategies for Transitioning to Zero-Emission Vehicles--  

E-Print Network [OSTI]

or organization) US DOT $38,875 Total Project Cost $38,875 Agency ID or Contract Number DTRT13-G-UTC29 StartProject Information Form Project Title White Paper on Strategies for Transitioning to Zero and End Dates July 2014 to September 2014 Brief Description of Research Project Zero-emission vehicles

California at Davis, University of

137

Washing out of the 0-transition in Josephson junctions R. Avriller1  

E-Print Network [OSTI]

Washing out of the 0- transition in Josephson junctions R. Avriller1 and F. Pistolesi1 1 Univ: July 21, 2014) We consider a Josephson junction formed by a quantum dot connected to two bulk numbers: 73.23.-b, 74.25.F-, 74.50.+r, 74.45.+c Introduction.-- The Josephson junction is a fun- damental

Boyer, Edmond

138

Testing the effectiveness of an acoustic deterrent for gray whales along the Oregon coast  

SciTech Connect (OSTI)

This study was conducted to determine whether a low-powered sound source could be effective at deterring gray whales from areas that may prove harmful to them. With increased interest in the development of marine renewal energy along the Oregon coast the concern that such development may pose a collision or entanglement risk for gray whales. A successful acoustic deterrent could act as a mitigation tool to prevent harm to whales from such risks. In this study, an acoustic device was moored on the seafloor in the pathway of migrating gray whales off Yaquina Head on the central Oregon coast. Shore-based observers tracked whales with a theodolite (surveyor’s tool) to accurately locate whales as they passed the headland. Individual locations of different whales/whale groups as well as tracklines of the same whale/whale groups were obtained and compared between times with the acoustic device was transmitting and when it was off. Observations were conducted on 51 d between January 1 and April 15, 2012. A total of 143 individual whale locations were collected for a total of 243 whales, as well as 57 tracklines for a total of 142 whales. Inclement weather and equipment problems resulted in very small sample sizes, especially during experimental periods, when the device was transmitting. Because of this, the results of this study were inconclusive. We feel that another season of field testing is warranted to successfully test the effectiveness of the deterrent, but recommend increasing the zone of influence to 3 km to ensure the collection of adequate sample sizes. Steps have been taken to acquire the necessary federal research permit modification to authorize the increased zone of influence and to modify the acoustic device for the increased power. With these changes we are confident we will be able to determine whether the deterrent is effective at deflecting gray whales. A successful deterrent device may serve as a valuable mitigation tool to protect gray whales, and other baleen whales, in the event that marine energy development poses a collision or entanglement risk.

Lagerquist, Barbara [Oregon State University Marine Mammal Institute; Winsor, Martha [Oregon State University Marine Mammal Institute; Mate, Bruce [Oregon State University Marine Mammal Institute

2012-12-31T23:59:59.000Z

139

Women @ Energy: Dot Harris | Department of Energy  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomen Owned SmallOf TheViolations | DepartmentDeborah Joanne Bard Women @Dot Harris

140

Temperature Dependence of Single CdSe/ZnS Quantum Dots Luminescence Lifetime  

E-Print Network [OSTI]

, such as quantum dots (QDs), has grown dramatically. These semiconductor QDs bridge the gap between single

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Alameda-Contra Costa Transit District (AC Transit) Fuel Cell...  

Energy Savers [EERE]

(AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results This...

142

Linewidth broadening of a quantum dot coupled to an off-resonant cavity  

E-Print Network [OSTI]

We study the coupling between a photonic crystal cavity and an off-resonant quantum dot under resonant excitation of the cavity or the quantum dot. Linewidths of the quantum dot and the cavity as a function of the excitation laser power are measured. We show that the linewidth of the quantum dot, measured by observing the cavity emission, is significantly broadened compared to the theoretical estimate. This indicates additional incoherent coupling between the quantum dot and the cavity.

Arka Majumdar; Andrei Faraon; Erik Kim; Dirk Englund; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

2010-03-11T23:59:59.000Z

143

Coherent excitation of a strongly coupled quantum dot - cavity system  

E-Print Network [OSTI]

We have studied the coherent excitation of a strongly coupled QD/photonic crystal cavity system. Time-resolved reflectivity measurements show the vacuum Rabi oscillation of the dot in the cavity. Next, we considered the resonant driving of a cavity-detuned dot, which efficiently populates the cavity mode. This cavity-controlled read-out channel allows high-resolution single quantum dot spectroscopy. Autocorrelation measurements on the cavity mode show antibunching and suggest the use of the resonantly driven QD/cavity system as an on-demand source of single photons with potentially near-unity indistinguishability.

Dirk Englund; Arka Majumdar; Andrei Faraon; Mitsuru Toishi; Nick Stoltz; Pierre Petroff; Jelena Vuckovic

2009-02-19T23:59:59.000Z

144

The FBI wavelet/scalar quantization standard for gray-scale fingerprint image compression  

SciTech Connect (OSTI)

The FBI has recently adopted a standard for the compression of digitized 8-bit gray-scale fingerprint images. The standard is based on scalar quantization of a 64-subband discrete wavelet transform decomposition of the images, followed by Huffman coding. Novel features of the algorithm include the use of symmetric boundary conditions for transforming finite-length signals and a subband decomposition tailored for fingerprint images scanned at 500 dpi. The standard is intended for use in conjunction with ANSI/NBS-CLS 1-1993, American National Standard Data Format for the Interchange of Fingerprint Information, and the FBI's Integrated Automated Fingerprint Identification System.

Bradley, J.N.; Brislawn, C.M. (Los Alamos National Lab., NM (United States)); Hopper, T. (Federal Bureau of Investigation, Washington, DC (United States))

1993-01-01T23:59:59.000Z

145

The FBI wavelet/scalar quantization standard for gray-scale fingerprint image compression  

SciTech Connect (OSTI)

The FBI has recently adopted a standard for the compression of digitized 8-bit gray-scale fingerprint images. The standard is based on scalar quantization of a 64-subband discrete wavelet transform decomposition of the images, followed by Huffman coding. Novel features of the algorithm include the use of symmetric boundary conditions for transforming finite-length signals and a subband decomposition tailored for fingerprint images scanned at 500 dpi. The standard is intended for use in conjunction with ANSI/NBS-CLS 1-1993, American National Standard Data Format for the Interchange of Fingerprint Information, and the FBI`s Integrated Automated Fingerprint Identification System.

Bradley, J.N.; Brislawn, C.M. [Los Alamos National Lab., NM (United States); Hopper, T. [Federal Bureau of Investigation, Washington, DC (United States)

1993-05-01T23:59:59.000Z

146

Application of Gray codes to the study of the theory of symbolic dynamics of unimodal maps  

E-Print Network [OSTI]

In this paper we provide a closed mathematical formulation of our previous results in the field of symbolic dynamics of unimodal maps. This being the case, we discuss the classical theory of applied symbolic dynamics for unimodal maps and its reinterpretation using Gray codes. This connection was previously emphasized but no explicit mathematical proof was provided. The work described in this paper not only contributes to the integration of the different interpretations of symbolic dynamics of unimodal maps, it also points out some inaccuracies that exist in previous works.

David Arroyo; Gonzalo Alvarez

2012-04-29T23:59:59.000Z

147

Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation  

SciTech Connect (OSTI)

A dramatically enhanced self-assembly of GeSi quantum dots (QDs) is disclosed on slightly miscut Si (001) substrates, leading to extremely dense QDs and even a growth mode transition. The inherent mechanism is addressed in combination of the thermodynamics and the growth kinetics both affected by steps on the vicinal surface. Moreover, temperature-dependent photoluminescence spectra from dense GeSi QDs on the miscut substrate demonstrate a rather strong peak persistent up to 300 K, which is attributed to the well confinement of excitons in the dense GeSi QDs due to the absence of the wetting layer on the miscut substrate.

Zhou, Tong; Zhong, Zhenyang, E-mail: zhenyangz@fudan.edu.cn [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China)

2014-02-01T23:59:59.000Z

148

Effect of Ligands on Characteristics of (CdSe)13 Quantum Dot  

SciTech Connect (OSTI)

The widespread applications of quantum dots (QDs) have spurred an increasing interest in the study of their coating ligands, which can not only protect the electronic structures of the central QDs, but also control their permeability through biological membranes with both size and shape. In this work, we have used density functional theory (DFT) to investigate the electronic structures of (CdSe)13 passivated by OPMe2(CH2)nMe ligands with different lengths and various numbers of branches (Me=methyl group, n = 0, 1-3). Our results show that the absorption peak in the ultraviolet-visible (UV-vis) spectra displays a clear blue-shift, on the scale of ~100 nm, upon the binding of ligands. Once the total number of ligands bound with (CdSe)13 reached a saturated number (9 or 10), no more blue-shift occurred in the absorption peak in the UV-vis spectra. On the other hand, the aliphatic chain length of ligands has a negligible effect on the optical properties of the QD core. Analyses of the bonding characteristics confirm that optical transitions are dominantly governed by the central QD core rather than the organic passivation. Interestingly, the density of states (DOS) share similar characteristics as vibrational spectra, even though there is no coordination vibration mode between the ligands and the central QD. These findings might provide insights on the material design for the passivation of quantum dots for biomedical applications.

Gao, Yang; Zhou, Bo; Kang, Seung-gu; Xin, Minsi; Yang, Ping; Dai, Xing; Wang, Zhigang; Zhou, Ruhong

2014-01-01T23:59:59.000Z

149

Hybrid organic/quantum dot thin film structures and devices  

E-Print Network [OSTI]

Organic light emitting diodes have undergone rapid advancement over the course of the past decade. Similarly, quantum dot synthesis has progressed to the point that room temperature highly efficient photoluminescence can ...

Coe-Sullivan, Seth (Seth Alexander)

2005-01-01T23:59:59.000Z

150

Self-Sustaining Dynamical Nuclear Polarization Oscillations in Quantum Dots  

E-Print Network [OSTI]

Early experiments on spin-blockaded double quantum dots revealed robust, large-amplitude current oscillations in the presence of a static (dc) source-drain bias. Despite experimental evidence implicating dynamical nuclear ...

Rudner, M. S.

151

Optoelectronic and photonic control of single quantum dots  

E-Print Network [OSTI]

Optoelectronic and photonic control of single quantum dots Samuel James Dewhurst Wolfson College University of Cambridge A thesis submitted for the degree of Doctor of Philosophy April 2010 Declaration This thesis describes work carried out...

Dewhurst, Samuel James

2010-10-12T23:59:59.000Z

152

Application of Mn/DOT Utility Coordination Process to Local Agencies Based on national best practices, the Minnesota Department of Transportation (Mn/DOT) Utility  

E-Print Network [OSTI]

Application of Mn/DOT Utility Coordination Process to Local Agencies Based on national best practices, the Minnesota Department of Transportation (Mn/DOT) Utility Coordination Process incorporates Processes There are projects where the full process is not necessary. The Mn/DOT Utilities Manual provides

Minnesota, University of

153

Scalable quantum computer architecture with coupled donor-quantum dot qubits  

DOE Patents [OSTI]

A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

2014-08-26T23:59:59.000Z

154

Fluorescence from a quantum dot and metallic nanosphere hybrid system  

SciTech Connect (OSTI)

We present energy absorption and interference in a quantum dot-metallic nanosphere system embedded on a dielectric substrate. A control field is applied to induce dipole moments in the nanosphere and the quantum dot, and a probe field is applied to monitor absorption. Dipole moments in the quantum dot or the metal nanosphere are induced, both by the external fields and by each other's dipole fields. Thus, in addition to direct polarization, the metal nanosphere and the quantum dot will sense one another via the dipole-dipole interaction. The density matrix method was used to show that the absorption spectrum can be split from one peak to two peaks by the control field, and this can also be done by placing the metal sphere close to the quantum dot. When the two are extremely close together, a self-interaction in the quantum dot produces an asymmetry in the absorption peaks. In addition, the fluorescence efficiency can be quenched by the addition of a metal nanosphere. This hybrid system could be used to create ultra-fast switching and sensing nanodevices.

Schindel, Daniel G. [Department of Mathematics and Statistics, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, R3B 2E9 (Canada); Singh, Mahi R. [Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 3K7 (Canada)

2014-03-31T23:59:59.000Z

155

Charge tuning in [111] grown GaAs droplet quantum dots  

SciTech Connect (OSTI)

We demonstrate charge tuning in strain free GaAs/AlGaAs quantum dots (QDs) grown by droplet epitaxy on a GaAs(111)A substrate. Application of a bias voltage allows the controlled charging of the QDs from ?3|e| to +2|e|. The resulting changes in QD emission energy and exciton fine-structure are recorded in micro-photoluminescence experiments at T?=?4?K. We uncover the existence of excited valence and conduction states, in addition to the s-shell-like ground state. We record a second series of emission lines about 25?meV above the charged exciton emission coming from excited charged excitons. For these excited interband transitions, a negative diamagnetic shift of large amplitude is uncovered in longitudinal magnetic fields.

Bouet, L.; Vidal, M.; Marie, X.; Amand, T.; Wang, G.; Urbaszek, B. [INSA-CNRS-UPS, LPCNO, Université de Toulouse, 135 Ave. Rangueil, 31077 Toulouse (France); Mano, T.; Ha, N.; Kuroda, T.; Sakoda, K. [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Durnev, M. V.; Glazov, M. M.; Ivchenko, E. L. [Ioffe Physical-Technical Institute RAS, 194021 St.-Petersburg (Russian Federation)

2014-08-25T23:59:59.000Z

156

Three-dimensional reconnection and relaxation of merging spheromak plasmas T. Gray, V. S. Lukin, M. R. Brown, and C. D. Cothran  

E-Print Network [OSTI]

Three-dimensional reconnection and relaxation of merging spheromak plasmas T. Gray, V. S. Lukin, M-dimensional reconnection and relaxation of merging spheromak plasmas" [Phys. Plasmas17, 102106 (2010)] Phys. Plasmas 17 and relaxation of merging spheromak plasmas T. Gray,1,a V. S. Lukin,2 M. R. Brown,1 and C. D. Cothran1,b 1

Brown, Michael R.

157

THE FABRICATION AND ANALYSIS OF QUANTUM-DOT THIN FILM LIGHT EMITTING DIODES FOR USE IN DISPLAYS TECHNOLOGIES.  

E-Print Network [OSTI]

??The quantum dot has many applications, one of which is the light emitting diode. Quantum dot light emitting diodes were fabricated for their use in… (more)

Pickering, Shawn

2011-01-01T23:59:59.000Z

158

Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark  

E-Print Network [OSTI]

Perturbation Growth at the Convective Scale G. Leoncini, R. S. Plant, S. L. Gray and P. A. Clark. Improvements in computational power mean that operational weather prediction models can now be run (during the entire simulation) of the perturbations. Diagnostics included root mean square precipitation

Plant, Robert

159

Wetlands Ecology and Management Instructors: Matthew Gray (mgray11@utk.edu) and Chris Graves (cgraves2@utk.edu)  

E-Print Network [OSTI]

WFS 340 Wetlands Ecology and Management Fall 2014 Instructors: Matthew Gray (mgray11@utk.htm Required Readings: Handed out in class or emailed. Recommended Text: Wetlands, 2007, 4th edition (ISBN 978-0-471-69967-5) or Wetlands, 2000, 3rd edition (ISBN 0-471-29232-X) Authors: William J. Mitsch and James G. Gosselink Course

Gray, Matthew

160

Wetlands Ecology and Management Instructors: Matthew Gray (mgray11@utk.edu) and Chris Graves (cgraves2@utk.edu)  

E-Print Network [OSTI]

WFS 340 Wetlands Ecology and Management Fall 2013 Instructors: Matthew Gray (mgray11@utk.htm Required Text: Wetland Restoration and Construction, 2011 (978-0-9834558-0-6) Author: Thomas Biebighauser Recommended Text: Wetlands, 2007, 4th edition (ISBN 978-0-471-69967-5) or Wetlands, 2000, 3rd edition (ISBN 0

Gray, Matthew

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

ADVANCED WETLAND ECOLOGY Instructors: Dr. Matthew Gray (mgray11@utk.edu); Dr. Heath Hagy (hhagy@utk.edu)  

E-Print Network [OSTI]

(all day workshop) Biebighauser (USFS) 17 Treatment Wetlands Ludwig (UT) 22 Optional Field TripWFS 536 ADVANCED WETLAND ECOLOGY Fall 2011 Instructors: Dr. Matthew Gray (mgray11@utk.edu); Dr Text: Wetlands, 2000, 3rd edition, Wiley (www.wiley.com, ISBN 047129232X) or Wetlands, 2007, 4th

Gray, Matthew

162

Fluorescent of C-dot composite thin films and its properties  

SciTech Connect (OSTI)

In the present work, we report the preparation of a fluorescent carbon nanodots (C-dots) epoxy composite thin films on a glass substrate. C-dots were prepared directly by a simple hydrothermal method using citric acid as a carbon source. The C-dots solutions were mixed with a transparent epoxy resin to form C-dot epoxy composite. Furthermore, the composite precursor was deposited on the glass substrate using a spin coating method in order to fabricate C-dot epoxy composite thin film. The transmittance intensity of C-dot composite film reached up to 90% in the visible light spectra. Using Swanopoel method, the film thickness of fabricated C-dot composite film was determined at about 1.45 ?m, a value lies in a typical range needed for a wide range application. Thus, the C-dot composite film is promising in broadening applications in various fields such as energy conversion, optoelectronics, and display technology.

Mahen, Ea Cahya Septia, E-mail: ferry@fi.itb.ac.id; Nuryadin, Bebeh W., E-mail: ferry@fi.itb.ac.id; Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id; Abdullah, Mikrajuddin, E-mail: ferry@fi.itb.ac.id; Khairurrijal, E-mail: ferry@fi.itb.ac.id [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung, 40132 (Indonesia)

2014-02-24T23:59:59.000Z

163

Manipulating surface diffusion and elastic interactions to obtain quantum dot multilayer arrangements over different length scales  

SciTech Connect (OSTI)

An innovative multilayer growth of InAs quantum dots on GaAs(100) is demonstrated to lead to self-aggregation of correlated quantum dot chains over mesoscopic distances. The fundamental idea is that at critical growth conditions is possible to drive the dot nucleation only at precise locations corresponding to the local minima of the Indium chemical potential. Differently from the known dot multilayers, where nucleation of new dots on top of the buried ones is driven by the surface strain originating from the dots below, here the spatial correlations and nucleation of additional dots are mostly dictated by a self-engineering of the surface occurring during the growth, close to the critical conditions for dot formation under the fixed oblique direction of the incoming As flux, that drives the In surface diffusion.

Placidi, E., E-mail: ernesto.placidi@ism.cnr.it; Arciprete, F. [Istituto di Struttura della Materia, CNR, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Università di Roma “Tor Vergata”, Dipartimento di Fisica, via della Ricerca Scientifica 1, 00133 Rome (Italy); Latini, V.; Latini, S.; Patella, F. [Università di Roma “Tor Vergata”, Dipartimento di Fisica, via della Ricerca Scientifica 1, 00133 Rome (Italy); Magri, R. [Dipartimento di Scienze Fisiche, Informatiche e Matematiche (FIM), Università di Modena e Reggio Emilia, and Centro S3 CNR-Istituto Nanoscienze, Via Campi 213/A, 4100 Modena (Italy); Scuderi, M.; Nicotra, G. [CNR-IMM, Strada VIII, 5, 95121 Catania (Italy)

2014-09-15T23:59:59.000Z

164

Fabrication and optimization of light emitting devices with core-shell quantum dots  

E-Print Network [OSTI]

Quantum dot light emitting devices (QD-LEDs) are promising options for the next generation of solid state lighting, color displays, and other optoelectronic applications. Overcoating quantum dots (QDs) -- semiconducting ...

Song, Katherine Wei

2013-01-01T23:59:59.000Z

165

Transit Rider Information King County Metro Transit  

E-Print Network [OSTI]

Transit Rider Information King County Metro Transit Rider Information (206) 553-3000 http the On the Move Blog http://www.seattle.gov/transportation King County Road Services Division Road Maintenance closely with King County Metro Transit, the Seattle School District, local universities, hospitals

Queitsch, Christine

166

Two-path transport measurements with bias dependence on a triple quantum dot  

SciTech Connect (OSTI)

We present transport measurements on a lateral triple quantum dot with a star-like geometry and one lead attached to each dot. The system is studied in a regime close to established quadruple points, where all three dots are in resonance. The specific sample structure allows us to apply two different bias voltages to the two source leads and thus to study the influence between the paths with serial double dots.

Kotzian, M.; Rogge, M. C.; Haug, R. J. [Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover (Germany)

2013-12-04T23:59:59.000Z

167

Midwave infrared quantum dot avalanche photodiode David A. Ramirez,a  

E-Print Network [OSTI]

Midwave infrared quantum dot avalanche photodiode David A. Ramirez,a Jiayi Shao, Majeed M. Hayat demonstration of a GaAs based avalanche photodiode APD operating in the midwave infrared region 3­5 m . In the device, called the quantum dot avalanche photodiode, an intersubband quantum dots-in-a-well detector

Hayat, Majeed M.

168

SU(4) Kondo Effect in Carbon Nanotube Quantum Dots: Kondo Effect without Charge Quantization  

E-Print Network [OSTI]

.J. Liang, M. Bockrath, and H. Park, PRL (2002) M. R. Buitelaar et al., PRL (2002) Quantization along length nanotube M.S. Choi, R. Lopez and R. Aguado, PRL (2005) 4 degenerate levels in the dot are coupled one for 1 electron: Double dots, dots with symmetries: D. Boese et al., PRB (2002) L. Borda et al., PRL

Finkelstein, Gleb

169

Self-organized formation of quantum dots of a material on a substrate  

DOE Patents [OSTI]

Systems and methods are described for fabricating arrays of quantum dots. A method for making a quantum dot device, includes: forming clusters of atoms on a substrate; and charging the clusters of atoms such that the clusters of atoms repel one another. The systems and methods provide advantages because the quantum dots can be ordered with regard to spacing and/or size.

Zhang, Zhenyu (232 Long Bow Rd., Knoxville, TN 37922); Wendelken, John F. (925 Suwanee Rd., Knoxville, TN 37923); Chang, Ming-Che (F4-2, No. 178 Sec 5 Minsheng East Rd., Taipei, TW); Pai, Woei Wu (1F, No. 17, Alley 11, Lane 202, Ming Chyuan Rd., Pan Chou City, Taipei County, TW)

2001-01-01T23:59:59.000Z

170

Tunable few-electron double quantum dots and Klein tunnelling in ultraclean carbon nanotubes  

E-Print Network [OSTI]

Tunable few-electron double quantum dots and Klein tunnelling in ultraclean carbon nanotubes G. A. Steele*, G. Gotz and L. P. Kouwenhoven Quantum dots defined in carbon nanotubes are a platform for both with highly tunable barriers1 , but disorder has prevented tunable nanotube- based quantum-dot devices from

171

FISH and Chips: Automation of Fluorescent Dot Counting in Interphase Cell Nuclei  

E-Print Network [OSTI]

) in each cell nucleus. This system works with two fluorescent dyes, one for the DNA hybridization dotsFISH and Chips: Automation of Fluorescent Dot Counting in Interphase Cell Nuclei Hans Netten,1 Ian abnormalities in inter- phase cell nuclei. This process is called dot counting. To estimate the distribution

van Vliet, Lucas J.

172

Temperature-Tuning of Near-Infrared Monodisperse Quantum Dot Solids at  

E-Print Network [OSTI]

include solar energy conversion as well as quantum communication. In quantum dot systems, the dot sizes photovoltaics, capturing the infrared spectrum, and also exhibiting possible multi- exciton generation.4. Incoherent Fo¨rster resonance energy transfer (FRET) 8­11 can occur between different-sized quantum dots

Hone, James

173

DOT-7A Type A packaging design guide  

SciTech Connect (OSTI)

The purpose of this Design Guide is to provide instruction for designing a U.S. Department of Transportation Specification 7A (DOT-7A) Type A packaging. Another purpose for this Design Guide is to support the evaluation and testing activities that are performed on new designs by a U.S. Department of Energy (DOE) test facility. This evaluation and testing program is called the DOT-7A Program. When an applicant has determined that a DOT-7A packaging is needed and not commercially available, a design may be created according to this document. The design should include a packaging drawing, specifications, analysis report, operating instructions, and a Packaging Qualification Checklist; all of which should be forwarded to a DOE/HQ approved test facility for evaluation and testing. This report is being submitted through the Engineering Documentation System so that it may be used for reference and information purposes.

Kelly, D.L.

1995-01-23T23:59:59.000Z

174

DOT-7A Type A packaging test and evaluation procedure  

SciTech Connect (OSTI)

The purpose of this document is to provide guidance for qualifying a DOT-7A Type A packaging for use. WHC qualifies DOT-7A packaging for two purposes. The first is to provide packages for use by WHC (manufacturer-qualified). The second is to provide a contracted service in support of DOE/EM-76 (DOE-qualified). This document includes descriptions of the performance tests, the personnel involved and their qualifications, appropriate safety and quality assurance considerations, and the procedures to be followed when WHC performs the tests (either as the manufacturer, or on behalf of the DOE`s certification program).

Kelly, D.L., Westinghouse Hanford

1996-06-13T23:59:59.000Z

175

Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix  

DOE Patents [OSTI]

A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.

Forrest, Stephen R. (Ann Arbor, MI)

2008-08-19T23:59:59.000Z

176

Components for quantum computing based on optical transitions in single quantum dots  

E-Print Network [OSTI]

, the valence band is normally full and the conduction band is normally empty. Carriers can be introduced into the QDs using a variety of methods ranging from electrical injection[8, 9], such as in a light emitting diode, to more exotic methods involving surface...

Pooley, Matthew Anthony

177

Ultrasmall silicon quantum dots F. A. Zwanenburg,1,a  

E-Print Network [OSTI]

by a model based on the Poisson equation. The smallest dots 12 nm allow identification of the last charge-down planar silicon devices,1­3 produced by etching bulk materials down to nanometer dimensions, often show understanding of the specific system. This has allowed us to realize the first experimental identification

178

Phonons in quantum dots and their role in exciton dephasing  

E-Print Network [OSTI]

-nitrides. Values are taken from [5]. The values for the nitride compounds are taken from density functional dots (QDs). The state of the art is reported in detail in the present book. A large application- driven the theory of acoustic phonons in QDs is explained in Sec. 3. Special emphasis is given to continuum

Zimmermann, Roland

179

TRICOLOR LIGHT EMITTING DIODE DOT MATRIX DISPLAY SYSTEM WITHAUDIO OUTPUT  

E-Print Network [OSTI]

1 TRICOLOR LIGHT EMITTING DIODE DOT MATRIX DISPLAY SYSTEM WITHAUDIO OUTPUT Grantham Pang, Chi emitting diodes; tricolor display; audio communication. I. Introduction This paper relates to a tricolor broadcasting through the visible light rays transmitted by the display panel or assembly. Keywords: light

Pang, Grantham

180

Circuit QED in a double quantum dot system  

SciTech Connect (OSTI)

Strong coupling peculiar feature is demonstrated in a coupled qubit-resonator system consisting of a GaAs double quantum dot and a coplanar waveguide resonator. Qubit-resonator coupling strength (g and the decoherence rate ? are directly derived from the experiment, assuring a strong coupling condition (g/? ? 2)

Toida, Hiraku; Nakajima, Takashi; Komiyama, Susumu [Department of Basic Science, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

2013-12-04T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Electronic structure of quantum dots Stephanie M. Reimann  

E-Print Network [OSTI]

Electronic structure of quantum dots Stephanie M. Reimann Mathematical Physics, Lund Institute are reviewed. Experimental techniques for measuring the electronic shell structure and the effect of magnetic fields are briefly described. The electronic structure is analyzed in terms of simple single

Wu, Zhigang

182

State DOT: Colorado State Report Questions on MEPDG Implementation  

E-Print Network [OSTI]

State DOT: Colorado State Report Questions on MEPDG Implementation 1. Summarize your state's status as far as MEPDG Implementation. Currently, CDOT is in the process of validating the MEPDG in Colorado and calibrating it to Colorado performance data. 2. What efforts have been made toward local calibration? CDOT has

183

Portland Cement Concrete Pavement Shannon Golden, Alabama DOT  

E-Print Network [OSTI]

Portland Cement Concrete Pavement Shannon Golden, Alabama DOT PORTLAND CEMENT CONCRETE PAVEMENT PROJECT · First in Alabama in more than 25 years! · IM-I059 (342) Etowah County ­ I-59 Concrete Pavement Rehabilitation with Unbonded Concrete Overlay ­ Length: 10.9 miles ­ Thickness: 11.0 to 13.5 inches ­ Volume: 300

184

Alabama DOT: Alabama Report Questions on NDT Testing  

E-Print Network [OSTI]

Alabama DOT: Alabama Report Questions on NDT Testing 1. What NDT testing methods for concrete materials, concrete pavements, and overlays are you trying? · We perform pavement smoothness testing, pavement friction testing and FWD testing · We are currently using GPR on the I-59 project to locate voids

185

State DOT: California State Report Questions on NDT Testing  

E-Print Network [OSTI]

test for this purpose. For concrete pavement, California has used falling weight deflectometer (FWD locations within concrete pavement. 2. In your experience, how does the reliability of NDT testing methodsState DOT: California State Report Questions on NDT Testing 1. What NDT testing methods

186

State DOT: Louisiana State Report Questions on NDT Testing  

E-Print Network [OSTI]

State DOT: Louisiana State Report Questions on NDT Testing 1. What NDT testing methods for concrete materials, concrete pavements, and overlays are you trying? LADOTD does not test concrete pavements or overlays non-destructively. We do use the surface resistivity meter for non-destructive testing

187

Quantum dot-based nanomaterials for biological imaging  

E-Print Network [OSTI]

Quantum dot-based fluorescent probes were synthesized and applied to biological imaging in two distinct size regimes: (1) 100-1000 nm and (2) < 10 nm in diameter. The larger diameter range was accessed by doping CdSe/ZnS ...

Zimmer, John P. (John Philip)

2006-01-01T23:59:59.000Z

188

Mn/DOT's Ombudsman Program Collaboration and Process  

E-Print Network [OSTI]

Mn/DOT's Ombudsman Program Collaboration and Process #12;Overview Ombudsman exists to rebuild trust on the environmental and municipal consent processes can be critical #12;A Large Organization #12;Tragedy;Ombudsman Does Not... ·! Advocate for one party or point of view ·! Own any formal process or policy

Minnesota, University of

189

A Review of "Women Writers and Public Debate in 17th-Century Britain" by Catharine Gray  

E-Print Network [OSTI]

Gray. Women Writers and Public Debate in 17th-Century Britain. New York: Houndmills, Basingstoke: Palgrave Macmillan, 2007. x + 262 pp. $69.95. Review by maurizio farina, university of palermo. Apparently remote from the open-minded salon debates... testimonies ?of an active and engaged citizenry who create[d] widespread debate? (19). Kate Chedgzoy. Women?s Writing in the British Atlantic World: Memory, Place and History, 1550-1700. Cambridge: Cambridge University Press, 2007. viii + 267 pp. $95...

Farina, Maurizio

2009-01-01T23:59:59.000Z

190

Health-hazard evaluation report HETA-86-053-1933, Gray Pprinting Company, Fostoria, Ohio  

SciTech Connect (OSTI)

The Gray Printing Company, located in Fostoria, Ohio was studied for potential employee exposures to solvents used in the offset-printing process at that site. The company produced 30 monthly magazines plus various commercial catalogs and brochures. The employment at the site was 185 persons. Equipment used in the production of printed material included photographic-typesetting and sheet-fed and roll fed offset lithographic printing processes. Over two workdays the sheet fed press operator's isopropanol exposures ranged from 247 to 501 mg/m/sup 3/ with personal breathing zone naphtha concentrations of 0.03 to 8.9 mg/m/sup 3/. The web press operator's naphtha exposures ranged from 0.03 to 7.7 mg/m/sup 3/. These workers were also exposed to low concentrations of isopropanol. The highest short term isopropanol exposure was 726 mg/m/sup 3/. Short term exposures to blanket and roller cleaning solvent were low, less than 10 mg/m/sup 3/. A higher than expected reporting of symptoms related to central nervous system depression, difficulty in concentrating, dizziness, cough, chest pain, and dry skin were noted among workers. The authors conclude that there was an increased prevalence of neurotoxic, respiratory, and skin problems among workers using organic solvents. Due to the prevalence of these symptoms, the authors recommend measures for reducing employee exposure to solvents.

Crandall, M.S.; Boiano, J.M.; Fidler, A.T.; Cantor, F.

1988-10-01T23:59:59.000Z

191

Low frequency gray-body factors and infrared divergences: rigorous results  

E-Print Network [OSTI]

Formal solutions to the mode equations for both spherically symmetric black holes and Bose-Einstein condensate acoustic black holes are obtained by writing the spatial part of the mode equation as a linear Volterra integral equation of the second kind. The solutions work for a massless minimally coupled scalar field in the s-wave or zero angular momentum sector for a spherically symmetric black hole and in the longitudinal sector of a 1D Bose-Einstein condensate acoustic black hole. These solutions are used to obtain in a rigorous way analytic expressions for the scattering coefficients and gray-body factors in the zero frequency limit. They are also used to study the infrared behaviors of the symmetric two-point function and two functions derived from it: the point-split stress-energy tensor for the massless minimally coupled scalar field in Schwarzschild-de Sitter spacetime and the density-density correlation function for a Bose-Einstein condensate acoustic black hole.

Anderson, Paul R; Balbinot, Roberto

2015-01-01T23:59:59.000Z

192

Gas turbine combustor transition  

DOE Patents [OSTI]

A method is described for converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit. 7 figs.

Coslow, B.J.; Whidden, G.L.

1999-05-25T23:59:59.000Z

193

Gas turbine combustor transition  

DOE Patents [OSTI]

A method of converting a steam cooled transition to an air cooled transition in a gas turbine having a compressor in fluid communication with a combustor, a turbine section in fluid communication with the combustor, the transition disposed in a combustor shell and having a cooling circuit connecting a steam outlet and a steam inlet and wherein hot gas flows from the combustor through the transition and to the turbine section, includes forming an air outlet in the transition in fluid communication with the cooling circuit and providing for an air inlet in the transition in fluid communication with the cooling circuit.

Coslow, Billy Joe (Winter Park, FL); Whidden, Graydon Lane (Great Blue, CT)

1999-01-01T23:59:59.000Z

194

Utah Transit Authority Creating a Model Transit  

E-Print Network [OSTI]

safely · Find, Fix, Follow Up #12;Safety Focus · Safety Culture Safety Ambassadors Safety First MomentUtah Transit Authority Creating a Model Transit Safety Organization Global Level Crossing Safety and Trespasser Prevention Symposium August 2014 Dave Goeres, PE Chief Safety Officer dgoeres@rideuta.com #12

Illinois at Urbana-Champaign, University of

195

Photocurrent spectrum study of a quantum dot single-photon detector based on resonant tunneling effect with near-infrared response  

SciTech Connect (OSTI)

We present the photocurrent spectrum study of a quantum dot (QD) single-photon detector using a reset technique which eliminates the QD's “memory effect.” By applying a proper reset frequency and keeping the detector in linear-response region, the detector's responses to different monochromatic light are resolved which reflects different detection efficiencies. We find the reset photocurrent tails up to 1.3??m wavelength and near-infrared (?1100?nm) single-photon sensitivity is demonstrated due to interband transition of electrons in QDs, indicating the device a promising candidate both in quantum information applications and highly sensitive imaging applications operating in relative high temperatures (>80?K).

Weng, Q. C. [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); An, Z. H., E-mail: anzhenghua@fudan.edu.cn, E-mail: luwei@mail.sitp.ac.cn [State Key Laboratory of Surface Physics and Institute of Advanced Materials, Fudan University, Shanghai 200433 (China); Xiong, D. Y.; Zhu, Z. Q. [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); Zhang, B.; Chen, P. P.; Li, T. X.; Lu, W., E-mail: anzhenghua@fudan.edu.cn, E-mail: luwei@mail.sitp.ac.cn [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

2014-07-21T23:59:59.000Z

196

Control of the direction and rate of nuclear spin flips in InAs quantum dots using detuned optical pulse trains  

E-Print Network [OSTI]

We find that detuning an optical pulse train from electronic transitions in quantum dots controls the direction of nuclear spin flips. The optical pulse train generates electron spins that precess about an applied magnetic field, with a spin component parallel to the field only for detuned pulses. This component leads to asymmetry in the nuclear spin flips, providing a way to produce a stable and precise value of the nuclear spin polarization. This effect is observed using two-color, time-resolved Faraday rotation and ellipticity.

S. G. Carter; A. Shabaev; Sophia E. Economou; T. A. Kennedy; A. S. Bracker; T. L. Reinecke

2009-01-16T23:59:59.000Z

197

Exploring size and state dynamics in CdSe quantum dots using two-dimensional electronic spectroscopy  

SciTech Connect (OSTI)

Development of optoelectronic technologies based on quantum dots depends on measuring, optimizing, and ultimately predicting charge carrier dynamics in the nanocrystal. In such systems, size inhomogeneity and the photoexcited population distribution among various excitonic states have distinct effects on electron and hole relaxation, which are difficult to distinguish spectroscopically. Two-dimensional electronic spectroscopy can help to untangle these effects by resolving excitation energy and subsequent nonlinear response in a single experiment. Using a filament-generated continuum as a pump and probe source, we collect two-dimensional spectra with sufficient spectral bandwidth to follow dynamics upon excitation of the lowest three optical transitions in a polydisperse ensemble of colloidal CdSe quantum dots. We first compare to prior transient absorption studies to confirm excitation-state-dependent dynamics such as increased surface-trapping upon excitation of hot electrons. Second, we demonstrate fast band-edge electron-hole pair solvation by ligand and phonon modes, as the ensemble relaxes to the photoluminescent state on a sub-picosecond time-scale. Third, we find that static disorder due to size polydispersity dominates the nonlinear response upon excitation into the hot electron manifold; this broadening mechanism stands in contrast to that of the band-edge exciton. Finally, we demonstrate excitation-energy dependent hot-carrier relaxation rates, and we describe how two-dimensional electronic spectroscopy can complement other transient nonlinear techniques.

Caram, Justin R.; Zheng, Haibin; Rolczynski, Brian S.; Griffin, Graham B.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Graduate Program in the Biophysical Sciences, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Dolzhnikov, Dmitriy S.; Talapin, Dmitri V. [Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

2014-02-28T23:59:59.000Z

198

Ordered quantum dot molecules and single quantum dots formed by self-organized anisotropic strain engineering  

SciTech Connect (OSTI)

An ordered lattice of lateral InAs quantum dot (QD) molecules is created by self-organized anisotropic strain engineering of an (In,Ga)As/GaAs superlattice (SL) template on GaAs(311)B by molecular-beam epitaxy, constituting a Turing pattern in solid state. The SL template and InAs QD growth conditions, such as the number of SL periods, growth temperatures, amount and composition of deposited (In,Ga)As, and insertion of Al-containing layers, are studied in detail for an optimized QD ordering within and among the InAs QD molecules on the SL template nodes, which is evaluated by atomic force microscopy. The average number of InAs QDs within the molecules is controlled by the thickness of the upper GaAs separation layer on the SL template and the (In,Ga)As growth temperature in the SL. The strain-correlated growth in SL template formation and QD ordering is directly confirmed by high-resolution x-ray diffraction. Ordered arrays of single InAs QDs on the SL template nodes are realized for elevated SL template and InAs QD growth temperatures together with the insertion of a second InAs QD layer. The InAs QD molecules exhibit strong photoluminescence (PL) emission up to room temperature. Temperature-dependent PL measurements exhibit an unusual behavior of the full width at half maximum, indicating carrier redistribution solely within the QD molecules.

Lippen, T. van; Noetzel, R.; Hamhuis, G.J.; Wolter, J.H. [European Institute of Telecommunication Technologies/Communication Technology, Basic Research and Applications (eiTT/COBRA) Inter-University Research Institute, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

2005-02-15T23:59:59.000Z

199

Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs  

SciTech Connect (OSTI)

Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

Hendra, P. I. B., E-mail: ib.hendra@gmail.com; Rahayu, F., E-mail: ib.hendra@gmail.com; Darma, Y., E-mail: ib.hendra@gmail.com [Physical Vapor Deposition Laboratory, Physics of Material Electronics Research, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24T23:59:59.000Z

200

A GENERAL CIRCULATION MODEL FOR GASEOUS EXOPLANETS WITH DOUBLE-GRAY RADIATIVE TRANSFER  

SciTech Connect (OSTI)

We present a new version of our code for modeling the atmospheric circulation on gaseous exoplanets, now employing a 'double-gray' radiative transfer scheme, which self-consistently solves for fluxes and heating throughout the atmosphere, including the emerging (observable) infrared flux. We separate the radiation into infrared and optical components, each with its own absorption coefficient, and solve standard two-stream radiative transfer equations. We use a constant optical absorption coefficient, while the infrared coefficient can scale as a power law with pressure; however, for simplicity, the results shown in this paper use a constant infrared coefficient. Here we describe our new code in detail and demonstrate its utility by presenting a generic hot Jupiter model. We discuss issues related to modeling the deepest pressures of the atmosphere and describe our use of the diffusion approximation for radiative fluxes at high optical depths. In addition, we present new models using a simple form for magnetic drag on the atmosphere. We calculate emitted thermal phase curves and find that our drag-free model has the brightest region of the atmosphere offset by {approx}12 Degree-Sign from the substellar point and a minimum flux that is 17% of the maximum, while the model with the strongest magnetic drag has an offset of only {approx}2 Degree-Sign and a ratio of 13%. Finally, we calculate rates of numerical loss of kinetic energy at {approx}15% for every model except for our strong-drag model, where there is no measurable loss; we speculate that this is due to the much decreased wind speeds in that model.

Rauscher, Emily [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721-0092 (United States); Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2012-05-10T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Resonant scattering of surface plasmon polaritons by dressed quantum dots  

SciTech Connect (OSTI)

The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.

Huang, Danhong; Cardimona, Dave [Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117 (United States); Easter, Michelle [Department of Mechanical Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, New Jersey 07030 (United States); Gumbs, Godfrey [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065 (United States); Maradudin, A. A. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Lin, Shawn-Yu [Department of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Zhang, Xiang [Department of Mechanical Engineering, 3112 Etcheverry Hall, University of California at Berkeley, Berkeley, California 94720 (United States)

2014-06-23T23:59:59.000Z

202

Features of the electronic spectrum in a type-I core - shell quantum dot  

SciTech Connect (OSTI)

The model is proposed, which allows one to solve the problem of finding the energy spectrum and the wave function of an electron in a type-I core - shell quantum dot. It is shown that the size of the core and shell can serve as control parameters for the optimisation of the energy structure of the quantum dot in order to obtain the real structures with desired electrophysical and optical properties. (quantum dots)

Igoshina, S E; Karmanov, A A [Penza State University, Penza (Russian Federation)

2013-01-31T23:59:59.000Z

203

Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation  

SciTech Connect (OSTI)

We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

Buljan, M. [Charles University in Prague, Prague 12116 (Czech Republic); Ruder Boskovic Institute, Zagreb 10000 (Croatia); Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P. [Ruder Boskovic Institute, Zagreb 10000 (Croatia); Drazic, G. [Jozef Stefan Institute, Ljubljana 1000 (Slovenia); Salamon, K. [Institute of Physics, Zagreb 10000 (Croatia); Bernstorff, S. [Sincrotrone Trieste, Basovizza 34012 (Italy); Holy, V. [Charles University in Prague, Prague 12116 (Czech Republic)

2009-08-10T23:59:59.000Z

204

Phonon-mediated coupling between quantum dots through an off-resonant microcavity  

E-Print Network [OSTI]

We present experimental results showing phonon-mediated coupling between two quantum dots embedded inside a photonic crystal microcavity. With only one of the dots being spectrally close to the cavity, we observe both frequency up-conversion and down-conversion of the pump light via a $\\sim1.2$ THz phonon. We demonstrate this process for both weak and strong regimes of dot-cavity coupling, and provide a simple theoretical model explaining our observations.

Arka Majumdar; Michal Bajcsy; Armand Rundquist; Erik Kim; Jelena Vuckovic

2011-11-30T23:59:59.000Z

205

Quantum optics and cavity QED with quantum dots in photonic crystals  

E-Print Network [OSTI]

This chapter will primarily focus on the studies of quantum optics with semiconductor, epitaxially grown quantum dots embedded in photonic crystal cavities. We will start by giving brief introductions into photonic crystals and quantum dots, then proceed with the introduction to cavity quantum electrodynamics (QED) effects, with a particular emphasis on the demonstration of these effects on the quantum dot-photonic crystal platform. Finally, we will focus on the applications of such cavity QED effects.

Jelena Vuckovic

2014-02-11T23:59:59.000Z

206

Optical Nonlinearities and Ultrafast Carrier Dynamics in Semiconductor Quantum Dots  

SciTech Connect (OSTI)

Low-dimensional semiconductors have attracted great interest due to the potential for tailoring their linear and nonlinear optical properties over a wide-range. Semiconductor nanocrystals (NC's) represent a class of quasi-zero-dimensional objects or quantum dots. Due to quantum cordhement and a large surface-to-volume ratio, the linear and nonlinear optical properties, and the carrier dynamics in NC's are significantly different horn those in bulk materials. napping at surface states can lead to a fast depopulation of quantized states, accompanied by charge separation and generation of local fields which significantly modifies the nonlinear optical response in NC's. 3D carrier confinement also has a drastic effect on the energy relaxation dynamics. In strongly confined NC's, the energy-level spacing can greatly exceed typical phonon energies. This has been expected to significantly inhibit phonon-related mechanisms for energy losses, an effect referred to as a phonon bottleneck. It has been suggested recently that the phonon bottleneck in 3D-confined systems can be removed due to enhanced role of Auger-type interactions. In this paper we report femtosecond (fs) studies of ultrafast optical nonlinearities, and energy relaxation and trap ping dynamics in three types of quantum-dot systems: semiconductor NC/glass composites made by high temperature precipitation, ion-implanted NC's, and colloidal NC'S. Comparison of ultrafast data for different samples allows us to separate effects being intrinsic to quantum dots from those related to lattice imperfections and interface properties.

Klimov, V.; McBranch, D.; Schwarz, C.

1998-08-10T23:59:59.000Z

207

Photovoltaic performance of ultra-small PbSe quantum dots  

E-Print Network [OSTI]

Y; Alivisatos, AP, Photovoltaic Devices Employing TernaryPhotovoltaic performance of ultra-small PbSe quantum dotsquantum dot, solar cell, photovoltaic, quantum size effect

Ma, Wanli

2014-01-01T23:59:59.000Z

208

Comment on "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"  

E-Print Network [OSTI]

This is a comment on PRL paper by A.P. Kirk "Analysis of quantum coherent semiconductor quantum dot p-i-n junction photovoltaic cells"

Scully, Marlan O

2010-01-01T23:59:59.000Z

209

A Graphene Quantum Dot with a Single Electron Transistor as Integrated Charge Sensor  

E-Print Network [OSTI]

We have developed an etching process to fabricate a quantum dot and a nearby single electron transistor as a charge detector in a single layer graphene. The high charge sensitivity of the detector is used to probe Coulomb diamonds as well as excited spectrum in the dot, even in the regime where the current through the quantum dot is too small to be measured by conventional transport means. The graphene based quantum dot and integrated charge sensor serve as an essential building block to form a solid-state qubit in a nuclear-spin-free quantum world.

Ling-Jun Wang; Gang Cao; Tao Tu; Hai-Ou Li; Cheng Zhou; Xiao-Jie Hao; Zhan Su; Guang-Can Guo; Guo-Ping Guo; Hong-Wen Jiang

2010-08-28T23:59:59.000Z

210

artificial quantum-dot helium: Topics by E-print Network  

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

Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells Biology and Medicine Websites Summary: to Third-Generation...

211

acid-capped cdse quantum-dot: Topics by E-print Network  

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

Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells Biology and Medicine Websites Summary: to Third-Generation...

212

Manipulating shear-induced non-equilibrium transitions by feedback control  

E-Print Network [OSTI]

Using Brownian Dynamics (BD) simulations we investigate non-equilibrium transitions of sheared colloidal films under controlled shear stress $\\sigma_{\\mathrm{xz}}$. In our approach the shear rate $\\dot\\gamma$ is a dynamical variable, which relaxes on a timescale $\\tau_c$ such that the instantaneous, configuration-dependent stress $\\sigma_{\\mathrm{xz}}(t)$ approaches a pre-imposed value. Investigating the dynamics under this "feedback-control" scheme we find unique behavior in regions where the flow curve $\\sigma_{\\mathrm{xz}}(\\dot\\gamma)$ of the uncontrolled system is monotonic. However, in non-monotonic regions our method allows to {\\em select} between dynamical states characterized by different in-plane structure and viscosities. Indeed, the final state strongly depends on $\\tau_c$ relative to an {\\em intrinsic} relaxation time of the uncontrolled system. The critical values of $\\tau_c$ are estimated on the basis of a simple model.

Tarlan A. Vezirov; Sascha Gerloff; Sabine H. L. Klapp

2014-11-04T23:59:59.000Z

213

Hydrogen Transition Infrastructure Analysis  

SciTech Connect (OSTI)

Presentation for the 2005 U.S. Department of Energy Hydrogen Program review analyzes the hydrogen infrastructure needed to accommodate a transitional hydrogen fuel cell vehicle demand.

Melendez, M.; Milbrandt, A.

2005-05-01T23:59:59.000Z

214

Commensurability effects induced by a periodic array of nanoscale anti-dots in Nb superconductor  

E-Print Network [OSTI]

Commensurability effects induced by a periodic array of nanoscale anti-dots in Nb superconductor A. PACS: 74.25.Ha; 74.76.)w Keywords: Nanostructures; Anti-dots; Commensurability 1. Introduction atomic layers on periodical substrate [5], magnetic bubble arrays [6] and the magnetically induced Wigner

Metlushko, Vitali

215

Large open telescope: size-upscaling from DOT to LOT Robert H. Hammerschlaga  

E-Print Network [OSTI]

Large open telescope: size-upscaling from DOT to LOT Robert H. Hammerschlaga , Aswin P. L. Jägersb, telescope drives 1. INTRODUCTION The Dutch Open Telescope (DOT) on the Canary island La Palma consists temperature homogeneous. No warm air bubbles are forced upwards against the closed wall of a tower and no heat

Rutten, Rob

216

Project Information Form Project Title White Paper on Climate Adaptation for State DOTs and Local Agencies  

E-Print Network [OSTI]

each agency or organization) DOT $30,000 Total Project Cost $30,000 Agency ID or Contract Number DTRT13Project Information Form Project Title White Paper on Climate Adaptation for State DOTs and Local-G-UTC29 Start and End Dates January 2014 to December 2014 Brief Description of Research Project

California at Davis, University of

217

Review paper: Toward highly efficient quantum-dot-and dye-sensitized solar cells  

E-Print Network [OSTI]

Review paper: Toward highly efficient quantum-dot- and dye-sensitized solar cells Hongsik Choi Interface control Light harvesting Tandem solar cell a b s t r a c t Dye- and quantum-dot-sensitized solar technologies of silicon-based solar cells should be resolved [7]. Dye-sensitized solar cells (DSSCs) have been

Park, Byungwoo

218

Evidence for formation of multi-quantum dots in hydrogenated graphene  

E-Print Network [OSTI]

Abstract We report the experimental evidence for the formation of multi-quantum dots in a hydrogenated single-layer graphene flake. The existence of multi-quantum dots is supported by the low-temperature measurements on a field effect transistor...

Chuang, Chiashain; Puddy, Reuben K; Connolly, Malcolm R; Lo, Shun-Tsung; Lin, Huang-De; Chen, Tse-Ming; Smith, Charles G; Liang, Chi-Te

2012-08-16T23:59:59.000Z

219

Rapid degradation of CdSe/ZnS colloidal quantum dots exposed to gamma irradiation  

E-Print Network [OSTI]

- grade their optical properties. In this paper, we report on the effects of gamma irradiationRapid degradation of CdSe/ZnS colloidal quantum dots exposed to gamma irradiation Nathan J. Withers of 137 Cs gamma irradiation on photoluminescent properties of CdSe/ZnS colloidal quantum dots

New Mexico, University of

220

Arrays of nanoscale magnetic dots: Fabrication by x-ray interference lithography and characterization  

SciTech Connect (OSTI)

X-ray interference lithography (XIL) was employed in combination with electrodeposition to fabricate arrays of nanoscale nickel dots which are uniform over 40 {mu}m and have periods down to 71 nm. Using extreme-ultraviolet light, XIL has the potential to produce magnetic dot arrays over large areas with periods well below 50 nm, and down to a theoretical limit of 6.5 nm for a 13 nm x-ray wavelength. In the nickel dot arrays, we observed the effect of interdot magnetic stray field interactions. Measuring the hysteresis loops using the magneto-optical Kerr effect, a double switching via the vortex state was observed in the nickel dots with diameters down to 44 nm and large dot separations. As the dot separations are reduced to below around 50 nm a single switching, occurring by collective rotation of the magnetic spins, is favored due to interdot magnetic stray field interactions. This results in magnetic flux closure through several dots which could be visualized with micromagnetic simulations. Further evidence of the stray field interactions was seen in photoemission electron microscopy images, where bands of contrast corresponding to chains of coupled dots were observed.

Heyderman, L.J.; Solak, H.H.; David, C.; Atkinson, D.; Cowburn, R.P.; Nolting, F. [Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Nanomagnetism Group, Department of Physics, University of Durham, Rochester Building, Science Laboratories, South Road, Durham DH1 3LE (United Kingdom); Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2004-11-22T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Bioimaging 4 (1996) 93106. Printed in the UK Fluorescent dot counting in  

E-Print Network [OSTI]

Bioimaging 4 (1996) 93­106. Printed in the UK Fluorescent dot counting in interphase cell nuclei allows the enumeration of chromosomal abnormalities in interphase cell nuclei. This process is called dot counting. To estimate the distribution of chromosomes per cell, a large number of cells have to be analysed

van Vliet, Lucas J.

222

Light extraction analysis and enhancement in a quantum dot light emitting diode  

E-Print Network [OSTI]

Light extraction analysis and enhancement in a quantum dot light emitting diode Ruidong Zhu outcoupling and angular performance of quantum dot light emitting diode (QLED). To illustrate the design principles, we use a red QLED as an example and compare its performance with an organic light emitting diode

Wu, Shin-Tson

223

Double-dot charge transport in Si single-electronhole transistors L. P. Rokhinson,a)  

E-Print Network [OSTI]

­oxide­ semiconductor field-effect transistors MOSFETs brought to light several issues related to the electrical beneath the dot transforming it into a free-standing bridge. Subsequently, 40 or 50 nm of oxide are thermally grown which further reduce the size of the dot. Polysilicon gate is deposited over the bridge

Rokhinson, Leonid

224

Mid Infrared Focal Plane Arrays With Nanoscale Quantum Dots and Superlattices  

E-Print Network [OSTI]

Mid Infrared Focal Plane Arrays With Nanoscale Quantum Dots and Superlattices S. Krishna Center- Molecular beam epitaxy, Nanoscale, Quantum Dots Superlattices, Antimonides, Mid-infrared photodetector. I. INTRODUCTION Presently, the state of the art photon detectors for the mid wave infrared (MWIR, 3-5 µm) and long

Krishna, Sanjay

225

Enlarged symmetry and coherence in arrays of quantum dots A. V. Onufriev and J. B. Marston  

E-Print Network [OSTI]

. A Hubbard model then describes a pillar array of coupled dots, and at half-filling the system can be mapped materials. Recent advances in nanofabrication tech- niques offer the possibility of constructing artificial- teractions that lift the degeneracy. However, as Stafford and Das Sarma noticed,3 semiconducting quantum dots

Onufriev, Alexey

226

Photovoltaic quantum dot quantum cascade infrared photodetector A. V. Barve and S. Krishna  

E-Print Network [OSTI]

Photovoltaic quantum dot quantum cascade infrared photodetector A. V. Barve and S. Krishna Citation subject to AIP license or copyright; see http://apl.aip.org/about/rights_and_permissions #12;Photovoltaic) Design and characterization of a quantum dot quantum cascade detector for photovoltaic midwave infrared

Krishna, Sanjay

227

Ambient-Processed Colloidal Quantum Dot Solar Cells via Individual Pre-Encapsulation of Nanoparticles  

E-Print Network [OSTI]

Ambient-Processed Colloidal Quantum Dot Solar Cells via Individual Pre-Encapsulation, 2010; E-mail: ted.sargent@utoronto.ca Solution-processed solar cells employing colloidal quantum dots-junction and tandem solar cells both rely on IR-band-gap semiconductors, there has been much recent emphasis

228

PHYSICAL REVIEW B 84, 205305 (2011) Spin-phonon coupling in single Mn-doped CdTe quantum dot  

E-Print Network [OSTI]

PHYSICAL REVIEW B 84, 205305 (2011) Spin-phonon coupling in single Mn-doped CdTe quantum dot C. L dynamics of a single Mn atom in a laser driven CdTe quantum dot is addressed theoretically. Recent of single Mn-doped CdTe dots, information about the quantum spin state of a single Mn atom is extracted from

Paris-Sud XI, Université de

229

Single photon emission from site-controlled InGaN/GaN quantum dots  

SciTech Connect (OSTI)

Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The single-photon nature of the emission was verified by the second-order correlation function up to 90?K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%–25% exhibited single photon emission at 10?K.

Zhang, Lei; Hill, Tyler A.; Deng, Hui, E-mail: dengh@umich.edu [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States)] [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States); Teng, Chu-Hsiang; Lee, Leung-Kway; Ku, Pei-Cheng, E-mail: peicheng@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)] [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

2013-11-04T23:59:59.000Z

230

Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier  

DOE Patents [OSTI]

A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

Forrest, Stephen R. (Ann Arbor, MI); Wei, Guodan (Ann Arbor, MI)

2010-07-06T23:59:59.000Z

231

Coupling of PbS Quantum Dots to Photonic Crystal Cavities at Room Temperature  

E-Print Network [OSTI]

We demonstrate the coupling of PbS quantum dot emission to photonic crystal cavities at room temperature. The cavities are defined in 33% Al, AlGaAs membranes on top of oxidized AlAs. Quantum dots were dissolved in Poly-methyl-methacrylate (PMMA) and spun on top of the cavities. Quantum dot emission is shown to map out the structure resonances, and may prove to be viable sources for room temperature cavity coupled single photon generation for quantum information processing applications. These results also indicate that such commercially available quantum dots can be used for passive structure characterization. The deposition technique is versatile and allows layers with different dot densities and emission wavelengths to be re-deposited on the same chip.

Ilya Fushman; Dirk Englund; Jelena Vuckovic

2005-05-14T23:59:59.000Z

232

Single photon absorption and dynamic control of a coupled quantum dot-cavity system  

E-Print Network [OSTI]

We theoretically investigate the dynamic interaction of a quantum dot in a nanocavity with timesymmetric single photon pulses. The simulations, based on a wavefunction approach, reveal that almost perfect single photon absorption occurs for quantum dot-cavity systems operating on the edge between strong and weak coupling regime. The computed maximum absorptions probability is close to unity for pulses with a typical length comparable to the half of the Rabi period. Furthermore, the dynamic control of the quantum dot energy via electric fields allows the freezing of the light-matter interaction leaving the quantum dot in its excited state. Shaping of single photon wavepackets by the electric field control is limited by the occurrence of chirping of the single photon pulse. This understanding of the interaction of single photon pulses with the quantum dot-cavity system provides the basis for the development of advanced protocols for quantum information processing in the solid state.

Robert Johne; Andrea Fiore

2011-10-11T23:59:59.000Z

233

Photoluminescence-enhanced biocompatible quantum dots by phospholipid functionalization  

SciTech Connect (OSTI)

A simple two-step strategy using phospholipid (PPL) to functionalize core/shell CdSe/ZnS quantum dots (QDs) has been described. The experimental data show that the use of S-H terminated PPL results not only in the high colloidal stability of core/shell CdSe/ZnS QDs in the aqueous phase, but also in the significant enhancement of photoluminescence. The degree of the enhancement is a function of the PPL-CdSe/ZnS QDs sample concentration. These results might be promising for future biological platform in new devices ranging from photovoltaic cells to biosensors and other devices.

Shi Yunfeng [School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); He Peng [Department of Chemistry, North Carolina State University, Raleigh, NC 27695 (United States)], E-mail: phe@ncsu.edu; Zhu Xinyuan [School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Instrumental Analysis Center, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)], E-mail: xyzhu@sjtu.edu.cn

2008-10-02T23:59:59.000Z

234

Electric Field effects on quantum correlations in semiconductor quantum dots  

E-Print Network [OSTI]

We study the effect of external electric bias on the quantum correlations in the array of optically excited coupled semiconductor quantum dots. The correlations are characterized by the quantum discord and concurrence and are observed using excitonic qubits. We employ the lower bound of concurrence for thermal density matrix at different temperatures. The effect of the F\\"orster interaction on correlations will be studied. Our theoretical model detects nonvanishing quantum discord when the electric field is on while concurrence dies, ensuring the existence of nonclassical correlations as measured by the quantum discord.

S. Shojaei; M. Mahdian; R. Yousefjani

2012-05-01T23:59:59.000Z

235

Activation of molecular catalysts using semiconductor quantum dots  

DOE Patents [OSTI]

Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.

Meyer, Thomas J. (Chapel Hill, NC); Sykora, Milan (Los Alamos, NM); Klimov, Victor I. (Los Alamos, NM)

2011-10-04T23:59:59.000Z

236

The red triangles are volcano locations. Dark-orange areas have a higher volcanic hazard; light-orange areas have a lower volcanic hazard. Dark-gray areas have a higher ash fall hazard;  

E-Print Network [OSTI]

The red triangles are volcano locations. Dark-orange areas have a higher volcanic hazard; light-orange areas have a lower volcanic hazard. Dark-gray areas have a higher ash fall hazard; light-gray areas have a lower ash fall hazard. Information is based on data during the past 10,000 years. Bottom, from left

Torgersen, Christian

237

Emerging factors associated with the decline of a gray fox population and multi-scale land cover associations of mesopredators in the Chicago metropolitan area.  

SciTech Connect (OSTI)

Statewide surveys of furbearers in Illinois indicate gray (Urocyon cinereoargenteus) and red (Vulpes vulpes) foxes have experienced substantial declines in relative abundance, whereas other species such as raccoons (Procyon lotor) and coyotes (Canis latrans) have exhibited dramatic increases during the same time period. The cause of the declines of gray and red foxes has not been identified, and the current status of gray foxes remains uncertain. Therefore, I conducted a large-scale predator survey and tracked radiocollared gray foxes from 2004 to 2007 in order to determine the distribution, survival, cause-specific mortality sources and land cover associations of gray foxes in an urbanized region of northeastern Illinois, and examined the relationships between the occurrence of gray fox and the presence other species of mesopredators, specifically coyotes and raccoons. Although generalist mesopredators are common and can reach high densities in many urban areas their urban ecology is poorly understood due to their secretive nature and wariness of humans. Understanding how mesopredators utilize urbanized landscapes can be useful in the management and control of disease outbreaks, mitigation of nuisance wildlife issues, and gaining insight into how mesopredators shape wildlife communities in highly fragmented areas. I examined habitat associations of raccoons, opossums (Didelphis virginiana), domestic cats (Felis catus), coyotes, foxes (gray and red), and striped skunks (Mephitis mephitis) at multiple spatial scales in an urban environment. Gray fox occurrence was rare and widely dispersed, and survival estimates were similar to other studies. Gray fox occurrence was negatively associated with natural and semi-natural land cover types. Fox home range size increased with increasing urban development suggesting that foxes may be negatively influenced by urbanization. Gray fox occurrence was not associated with coyote or raccoon presence. However, spatial avoidance and mortality due to coyote predation was documented and disease was a major mortality source for foxes. The declining relative abundance of gray fox in Illinois is likely a result of a combination of factors. Assessment of habitat associations indicated that urban mesopredators, particularly coyotes and foxes, perceived the landscape as relatively homogeneous and that urban mesopredators interacted with the environment at scales larger than that accommodated by remnant habitat patches. Coyote and fox presence was found to be associated with a high degree of urban development at large and intermediate spatial scales. However, at a small spatial scale fox presence was associated with high density urban land cover whereas coyote presence was associated with urban development with increased forest cover. Urban habitats can offer a diversity of prey items and anthropogenic resources and natural land cover could offer coyotes daytime resting opportunities in urban areas where they may not be as tolerated as smaller foxes. Raccoons and opossums were found to utilize moderately developed landscapes with interspersed natural and semi-natural land covers at a large spatial scale, which may facilitate dispersal movements. At intermediate and small spatial scales, both species were found to utilize areas that were moderately developed and included forested land cover. These results indicated that raccoons and opossums used natural areas in proximity to anthropogenic resources. At a large spatial scale, skunk presence was associated with highly developed landscapes with interspersed natural and semi-natural land covers. This may indicate that skunks perceived the urban matrix as more homogeneous than raccoons or opossums. At an intermediate spatial scale skunks were associated with moderate levels of development and increased forest cover, which indicated that they might utilize natural land cover in proximity to human-dominated land cover. At the smallest spatial scale skunk presence was associated with forested land cover surrounded by a suburban matrix. Compared to raccoon

Willingham, Alison N.; /Ohio State U.; ,

2008-01-01T23:59:59.000Z

238

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Second...  

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

Second Evaluation Report and Appendices Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Second Evaluation Report and Appendices This report describes operations at...

239

Accessibility-based transit planning  

E-Print Network [OSTI]

A method for evaluating transit planning proposals using accessibility metrics is advanced in this research. A transit-accessibility model is developed intended for use by in-house transit agency planning staff as a ...

Busby, Jeffrey R

2004-01-01T23:59:59.000Z

240

Quantum Dots-based Reverse Phase Protein Microarray  

SciTech Connect (OSTI)

CdSe nanocrystals, also called quantum dots (Qdots) are a novel class of fluorophores, which have a diameter of a few nanometers and possess high quantum yield, tunable emission wavelength and photostability. They are an attractive alternative to conventional fluorescent dyes. Quantum dots can be silanized to be soluble in aqueous solution under biological conditions, and thus be used in bio-detection. In this study, we established a novel Qdot-based technology platform that can perform accurate and reproducible quantification of protein concentration in a crude cell lysate background. Protein lysates have been spiked with a target protein, and a dilution series of the cell lysate with a dynamic range of three orders of magnitude has been used for this proof-of-concept study. The dilution series has been spotted in microarray format, and protein detection has been achieved with a sensitivity that is at least comparable to standard commercial assays, which are based on horseradish peroxidase (HRP) catalyzed diaminobenzidine (DAB) chromogenesis. The data obtained through the Qdot method has shown a close linear correlation between relative fluorescence unit and relative protein concentration. The Qdot results are in almost complete agreement with data we obtained with the well-established HRP-DAB colorimetric array (R{sup 2} = 0.986). This suggests that Qdots can be used for protein quantification in microarray format, using the platform presented here.

Shingyoji, Masato; Gerion, Daniele; Pinkel, Dan; Gray, Joe W.; Chen, Fanqing

2005-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Theory of dynamic nuclear polarization and feedback in quantum dots  

E-Print Network [OSTI]

An electron confined in a quantum dot interacts with its local nuclear spin environment through the hyperfine contact interaction. This interaction combined with external control and relaxation or measurement of the electron spin allows for the generation of dynamic nuclear polarization. The quantum nature of the nuclear bath, along with the interplay of coherent external fields and incoherent dynamics in these systems renders a wealth of intriguing phenomena seen in recent experiments such as electron Zeeman frequency focusing, hysteresis, and line dragging. We develop in detail a fully quantum, self-consistent theory that can be applied to such experiments and that moreover has predictive power. Our theory uses the operator sum representation formalism in order to incorporate the incoherent dynamics caused by the additional, Markovian bath, which in self-assembled dots is the vacuum field responsible for electron-hole optical recombination. The beauty of this formalism is that it reduces the complexity of the problem by encoding the joint dynamics of the external coherent and incoherent driving in an effective dynamical map that only acts on the electron spin subspace. This together with the separation of timescales in the problem allows for a tractable and analytically solvable formalism. The key role of entanglement between the electron spin and the nuclear spins in the formation of dynamic nuclear polarization naturally follows from our solution. We demonstrate the theory in detail for an optical pulsed experiment and present an in-depth discussion and physical explanation of our results.

Sophia E. Economou; Edwin Barnes

2014-04-06T23:59:59.000Z

242

Wildfire Policy in Transition Yellowstone  

E-Print Network [OSTI]

Wildfire Policy in Transition 1910 #12;Yellowstone 1988 #12;Colorado South Canyon Fire 1994 #12;#12;Wildfire Policy in Transition 1910 #12;

243

MATHEMATICS: RETHINKING THE TRANSITION  

E-Print Network [OSTI]

SENIOR SECONDARY MATHEMATICS: RETHINKING THE TRANSITION BILL BARTON THE UNIVERSITY OF AUCKLAND, NZ #12;THE ENVISIONING PROJECT · Mathematics education project of NZIMA (New Zealand Institute of Mathematics & Its Applications--the mathematics research funding body). · Brought together mathematics

Peters, Achim

244

Cancrinite: Crystal Structure, Phase Transitions, and Dehydration Behavior with Temperature  

SciTech Connect (OSTI)

The structural behavior of a cancrinite, Na{sub 5.96}Ca{sub 1.52}[Al{sub 6}Si{sub 6}O{sub 24}](CO{sub 3}){sub 1.57}{center_dot}1.75H{sub 2}O, was determined by using in situ synchrotron X-ray powder diffraction data [{lambda} = 0.91806(5) {angstrom}] at room pressure and from 25 to 982 {sup o}C. The sample was heated at a rate of about 9.5 {sup o}C/min, and X-ray traces were collected at about 15 {sup o}C intervals. The satellite reflections in cancrinite were lost at about 504 {sup o}C, where a phase transition occurs. All the unit-cell parameters for cancrinite also show a discontinuity at 504 {sup o}C. Initially, the [Ca{center_dot}CO{sub 3}] clusters and their vacancies are ordered in the channels, and this ordering is destroyed on heating to give rise to the phase transition. Cancrinite loses water continuously until about 625 {sup o}C; thereafter an anhydrous cancrinite phase exists. From 25 to 952 {sup o}C, a minimal amount of CO{sub 2} is lost from the structure. Over this temperature range, the average bridging angle, which is an indication of the degree of rotation of the tetrahedra, increases from 143.7(4) to 147.7(5){sup o}. Rotations of the tetrahedra are caused by expansion of the Na1-O2 bond lengths.

Hassan,I.; Antao, S.; Parise, J.

2006-01-01T23:59:59.000Z

245

Bus Centric Rapid Transit  

E-Print Network [OSTI]

Transfer Center TOD ? SmartCode/CNU Goals ? Public/private development partnership ? Emphasis on the pedestrian ? Bicycle and transit oriented development ? Dover Kohl TOD report, Dec. 2010 ? WTC will be anchor and terminus for BRT 11 18 Westside... Transfer Center 18 18 Five Points TOD #2 15 Five Points TOD 16 ? SmartCode/CNU Goals ? Public/private development partnership ? Emphasis on the pedestrian ? Bicycle and transit oriented development ? Dover Kohl TOD report, Dec. 2010 ? Five...

Banasiak, J.

2011-01-01T23:59:59.000Z

246

The impact of Greenland on the predictability of European weather systems Supervisors: Sue Gray (U. Reading), Ian Renfrew (U. East Anglia) and Richard Swinbank (Met  

E-Print Network [OSTI]

The impact of Greenland on the predictability of European weather systems Supervisors: Sue Gray (U-to-high latitude of Greenland means it has a major influence on the atmospheric circulation of the North Atlantic by the presence of Greenland as is the atmosphere well downstream, for example over the British Isles

Renfrew, Ian

247

IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 52, NO. 5, OCTOBER 2005 1271 Measurement of Centi-Gray X-Ray Dose  

E-Print Network [OSTI]

IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 52, NO. 5, OCTOBER 2005 1271 Measurement of Centi-Gray X- bination of single sheet higher film sensitivity to low energy X-rays along with a layered film dosimetryGy if required. Index Terms--Absorption spectra, gafchromic XR type T, low dose, radiation dosimetry

Yu, K.N.

248

Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions  

SciTech Connect (OSTI)

In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Buljan, M. [Ruder Boskovic Institute, Bijenicka cesta 54, Zagreb 10000 (Croatia); Chahboun, A. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Physics Department, FST Tanger, Tanger BP 416 (Morocco); Roldan, M. A.; Molina, S. I. [Departamento de Ciencia de los Materiales e Ing. Metalurgica y Q. I., Universidad de Cadiz, Cadiz (Spain); Bernstorff, S. [Sincrotrone Trieste, SS 14 km163, 5, Basovizza 34012 (Italy); Varela, M.; Pennycook, S. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Barradas, N. P.; Alves, E. [Instituto Superior Tecnico e Instituto Tecnologico e Nuclear-, EN10, Sacavem 2686-953 (Portugal)

2012-04-01T23:59:59.000Z

249

Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions  

SciTech Connect (OSTI)

In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

Pinto, S. [University of Minho, Portugal; Roldan Gutierrez, Manuel A [ORNL; Ramos, M. M.D. [University of Minho, Portugal; Gomes, M.J.M. [University of Minho, Portugal; Molina, S. I. [Universidad de Cadiz, Spain; Pennycook, Stephen J [ORNL; Varela del Arco, Maria [ORNL; Buljan, M. [R. Boskovic Institute, Zagreb, Croatia; Barradas, N. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Alves, E. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Chahboun, A. [FST Tanger, Morocco; Bernstorff, S. [Sincrotrone Trieste, Basovizza, Italy

2012-01-01T23:59:59.000Z

250

Green synthesis of highly efficient CdSe quantum dots for quantum-dots-sensitized solar cells  

SciTech Connect (OSTI)

Green synthesis of CdSe quantum dots for application in the quantum-dots-sensitized solar cells (QDSCs) is investigated in this work. The CdSe QDs were prepared with glycerol as the solvent, with sharp emission peak, full width at half maximum around 30?nm, and absorption peak from 475?nm to 510?nm. The reaction is environmental friendly and energy saving. What's more, the green synthesized CdSe QDs are coherence to the maximum remittance region of the solar spectrum and suitable as sensitizers to assemble onto TiO{sub 2} electrodes for cell devices application. What's more, the dynamic procedure of the carriers' excitation, transportation, and recombination in the QDSCs are discussed. Because the recombination of the electrons from the conduction band of TiO{sub 2}'s to the electrolyte affects the efficiency of the solar cells greatly, 3-Mercaptopropionic acid capped water-dispersible QDs were used to cover the surface of TiO{sub 2}. The resulting green synthesized CdSe QDSCs with Cu{sub 2}S as the electrode show a photovoltaic performance with a conversion efficiency of 3.39%.

Gao, Bing; Shen, Chao; Zhang, Mengya; Yuan, Shuanglong; Yang, Yunxia, E-mail: yangyunxia@ecust.edu.cn, E-mail: grchen@ecust.edu.cn; Chen, Guorong, E-mail: yangyunxia@ecust.edu.cn, E-mail: grchen@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Bo [Department of Physics, East China University of Science and Technology, Shanghai 200237 (China)

2014-05-21T23:59:59.000Z

251

Ceramic wire and coil made of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} high-temperature superconductor with a critical current density up to 75 A {center_dot}cm{sup {minus}2} at 77 K  

SciTech Connect (OSTI)

Processing parameters are refined and a route is found for fabricating wires, coils, and other lengthy electrotechnical elements form high-temperature superconducting ceramic YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}. The superconducting transition temperature of around 90 K and a critical current density in the terrestrial magnetic field of 35-75 A {center_dot} cm{sup {minus}2} at 77 K characterize the performance of the wire.

Basalaeva, T.S.; Ordan`yan, S.S.; Polonskii, Y.A. [St. Petersburg State Technical Univ. (Russian Federation)] [and others

1995-03-20T23:59:59.000Z

252

Real-time observation of nanoscale topological transitions in epitaxial PbTe/CdTe heterostructures  

SciTech Connect (OSTI)

The almost completely immiscible PbTe/CdTe heterostructure has recently become a prototype system for self-organized quantum dot formation based on solid-state phase separation. Here, we study by real-time transmission electron microscopy the topological transformations of two-dimensional PbTe-epilayers into, first, a quasi-one-dimensional percolation network and subsequently into zero-dimensional quantum dots. Finally, the dot size distribution coarsens by Ostwald ripening. The whole transformation sequence occurs during all stages in the fully coherent solid state by bulk diffusion. A model based on the numerical solution of the Cahn-Hilliard equation reproduces all relevant morphological and dynamic aspects of the experiments, demonstrating that this standard continuum approach applies to coherent solids down to nanometer dimensions. As the Cahn-Hilliard equation does not depend on atomistic details, the observed morphological transformations are general features of the model. To confirm the topological nature of the observed shape transitions, we developed a parameter-free geometric model. This, together with the Cahn-Hilliard approach, is in qualitative agreement with the experiments.

Groiss, H., E-mail: heiko.groiss@jku.at, E-mail: istvan.daruka@jku.at; Daruka, I., E-mail: heiko.groiss@jku.at, E-mail: istvan.daruka@jku.at; Springholz, G.; Schäffler, F. [Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz 4040 (Austria); Koike, K.; Yano, M. [Nanomaterials Microdevices Research Center, Osaka Institute of Technology, Asahi-ku Ohmiya, Osaka 535-8585 (Japan); Hesser, G. [Center for Surface- and Nanoanalytics (ZONA), Johannes Kepler University, Linz 4040 (Austria); Zakharov, N.; Werner, P. [Max Planck Institute of Microstructure Physics, Halle 06120 (Germany)

2014-01-01T23:59:59.000Z

253

Real-time effective-action approach to the Anderson quantum dot  

E-Print Network [OSTI]

The non-equilibrium time evolution of an Anderson quantum dot is investigated. The quantum dot is coupled between two leads forming a chemical-potential gradient. We use Kadanoff-Baym dynamic equations within a non-perturbative resummation of the s-channel bubble chains. The effect of the resummation leads to the introduction of a frequency-dependent 4-point vertex. The tunneling to the leads is taken into account exactly. The method allows the determination of the transient as well as stationary transport through the quantum dot, and results are compared with different schemes discussed in the literature (fRG, ISPI, tDMRG and QMC).

Sexty, Denes; Pawlowski, Jan

2010-01-01T23:59:59.000Z

254

Real-time effective-action approach to the Anderson quantum dot  

E-Print Network [OSTI]

The non-equilibrium time evolution of an Anderson quantum dot is investigated. The quantum dot is coupled between two leads forming a chemical-potential gradient. We use Kadanoff-Baym dynamic equations within a non-perturbative resummation of the s-channel bubble chains. The effect of the resummation leads to the introduction of a frequency-dependent 4-point vertex. The tunneling to the leads is taken into account exactly. The method allows the determination of the transient as well as stationary transport through the quantum dot, and results are compared with different schemes discussed in the literature (fRG, ISPI, tDMRG and QMC).

Denes Sexty; Thomas Gasenzer; Jan Pawlowski

2010-12-20T23:59:59.000Z

255

Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dot  

E-Print Network [OSTI]

We show theoretically and experimentally the existence of a new quantum interference(QI) effect between the electron-hole interactions and the scattering by a single Mn impurity. Theoretical model, including electron-valence hole correlations, the short and long range exchange interaction of Mn ion with the heavy hole and with electron and anisotropy of the quantum dot, is compared with photoluminescence spectroscopy of CdTe dots with single magnetic ions. We show how design of the electronic levels of a quantum dot enable the design of an exciton, control of the quantum interference and hence engineering of light-Mn interaction.

Trojnar, A; Kadantsev, E; Hawrylak, P; Goryca, M; Kazimierczuk, T; Kossacki, P; Wojnar, P; Potemski, M

2011-01-01T23:59:59.000Z

256

Quantum interference in exciton-Mn spin interactions in a CdTe semiconductor quantum dot  

E-Print Network [OSTI]

We show theoretically and experimentally the existence of a new quantum interference(QI) effect between the electron-hole interactions and the scattering by a single Mn impurity. Theoretical model, including electron-valence hole correlations, the short and long range exchange interaction of Mn ion with the heavy hole and with electron and anisotropy of the quantum dot, is compared with photoluminescence spectroscopy of CdTe dots with single magnetic ions. We show how design of the electronic levels of a quantum dot enable the design of an exciton, control of the quantum interference and hence engineering of light-Mn interaction.

A. Trojnar; M. Korkusinski; E. Kadantsev; P. Hawrylak; M. Goryca; T. Kazimierczuk; P. Kossacki; P. Wojnar; M. Potemski

2011-05-04T23:59:59.000Z

257

Gates controlled parallel-coupled double quantum dot on both single layer and bilayer graphene  

E-Print Network [OSTI]

Here we report the fabrication and quantum transport measurements of gates controlled parallel-coupled double quantum dot on both bilayer and single layer graphene. It is shown that the interdot coupling strength of the parallel double dots can be effectively tuned from weak to strong regime by both the in-plane plunger gates and back gate. All the relevant energy scales and parameters of the graphene parallel-coupled double dot can be extracted from the honeycomb charge stability diagrams revealed through the transport measurements.

Lin-Jun Wang; Guo-Ping Guo; Da Wei; Gang Cao; Tao Tu; Ming Xiao; Guang-Can Guo; A. M. Chang

2011-04-22T23:59:59.000Z

258

Far off-resonant coupling between photonic crystal microcavity and single quantum dot with resonant excitation  

SciTech Connect (OSTI)

In this paper, we experimentally demonstrate that with sub-nanowatt coherent s-shell excitation of a single InAs quantum dot, off-resonant coupling of 4.1?nm is possible between L3 photonic crystal microcavity and the quantum dot at 50?K. This resonant excitation reduces strongly the effect of surrounding charges to quantum dot, multiexciton complexes and pure dephasing. It seems that this far off-resonant coupling is the result of increased number of acoustical phonons due to high operating temperature of 50?K. The 4.1?nm detuning is the largest amount for this kind of coupling.

Banihashemi, Mehdi; Ahmadi, Vahid, E-mail: v-ahmadi@modares.ac.ir [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of)] [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of); Nakamura, Tatsuya; Kojima, Takanori; Kojima, Kazunobu; Noda, Susumu [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)] [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

2013-12-16T23:59:59.000Z

259

Theory of Electro-optic Modulation via a Quantum Dot Coupled to a Nano-resonator  

E-Print Network [OSTI]

In this paper, we analyze the performance of an electro-optic modulator based on a single quantum dot strongly coupled to a nano-resonator, where electrical control of the quantum dot frequency is achieved via quantum confined Stark effect. Using realistic system parameters, we show that modulation speeds of a few tens of GHz are achievable with this system, while the energy per switching operation can be as small as 0.5 fJ. In addition, we study the non-linear distortion, and the effect of pure quantum dot dephasing on the performance of the modulator.

Arka Majumdar; Nicolas Manquest; Andrei Faraon; Jelena Vuckovic

2009-11-27T23:59:59.000Z

260

Optical spectra and intensities of graphene magnetic dot bound to a negatively charged Coulomb impurity  

SciTech Connect (OSTI)

Employing numerical diagonalization, we study the optical properties of an electron in a monolayer-graphene magnetic dot bound to an off-center negatively charged Coulomb impurity based on the massless Dirac-Weyl model. Numerical results show that, since the electron-hole symmetry is broken by the Coulomb potential, the optical absorption spectra of the magnetic dot in the presence of a Coulomb impurity are different between the electron states and the hole states. Effects of both the magnetic field and the dot size on the absorption coefficient are presented as functions of the incident photon energies.

Lee, C. M., E-mail: mesimon-hk@yahoo.com.hk, E-mail: apkschan@cityu.edu.hk; Chan, K. S., E-mail: mesimon-hk@yahoo.com.hk, E-mail: apkschan@cityu.edu.hk [Department of Physics and Materials Science and Center for Functional Photonics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Shenzhen Research Institute, City University of Hong Kong, Shenzhen (China)

2014-07-28T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Certificate in Transit Management and  

E-Print Network [OSTI]

Certificate in Transit Management and Operations UMass Transit, in partnership with the UMass Transportation Center and CTTransit, are pleased to offer "A Certificate in Transit Management and Operations Engineering and the School of Management - Internships with UMass Transit and CTTransit - A summer workshop

Massachusetts at Amherst, University of

262

Certificate in Transit Management and  

E-Print Network [OSTI]

Certificate in Transit Management and Operations UMass Transit, in partnership with the UMass Transportation Center and CTTransit, are pleased to offer "A Certificate in Transit Management and Operations contract to provide transit management services in Hartford and other cities in Connecticut. CTTRANSIT

Massachusetts at Amherst, University of

263

Examining hydrogen transitions.  

SciTech Connect (OSTI)

This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.

Plotkin, S. E.; Energy Systems

2007-03-01T23:59:59.000Z

264

Energy spectra of two electrons in a circular quantum dot  

E-Print Network [OSTI]

The electron interaction energy of two interacting electrons in a circular quantum dot (with hard wall confinement) is investigated in the framework of the semi-classical Wentzel-Kramers-Brillouin (WKB) approximation. The two electrons are assumed to be in an infinitely deep well of radius $r_0$, in a simple configuration with one electron fixed at the origin. The corresponding Schrodinger equation, with hard wall boundary conditions, is also solved exactly by numerical integration. It is observed that the agreement between the two energy values is quite good, suggesting that the WKB approximation works well for such a confined quantum system as well. This may provide motivation to extend this to more realistic confined potentials.

Anjana Sinha; Y. P. Varshni

2002-08-27T23:59:59.000Z

265

Location deterministic biosensing from quantum-dot-nanowire assemblies  

SciTech Connect (OSTI)

Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10?nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices.

Liu, Chao [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Kim, Kwanoh [Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Fan, D. L., E-mail: dfan@austin.utexas.edu [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States)

2014-08-25T23:59:59.000Z

266

High performance tunnel injection quantum dot comb laser  

SciTech Connect (OSTI)

A high-speed multiwavelength quantum dot comb laser, grown by molecular beam epitaxy, is demonstrated. The device is characterized with a 75.9 nm (full width at half maximum) and a 91.4 nm (DELTA{sub -15dB}) wide lasing spectrum. There are 105 and 185 simultaneously emitted longitudinal modes with a maximum channel intensity nonuniformity of less than 3 dB in the spectral range of 1231-1252 nm and 1274-1311 nm, respectively, for a laser with 1040 mum cavity length. The channel spacing can be tuned with cavity length and remains invariant in the temperature range of 300-323 K. The small signal modulation bandwidth is 7.5 GHz.

Lee, C.-S.; Guo Wei; Basu, Debashish; Bhattacharya, Pallab [Department of Electrical Engineering and Computer Science, Solid State Electronics Laboratory, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

2010-03-08T23:59:59.000Z

267

Fluorescence quenching of CdSe quantum dots on graphene  

SciTech Connect (OSTI)

We studied systematically the fluorescence quenching of CdSe quantum dots (QDs) on graphene and its multilayers, as well as graphene oxide (GO) and reduced graphene oxide (rGO). Raman intensity of QDs was used as a quantitatively measurement of its concentration in order to achieve a reliable quenching factor (QF). It was found that the QF of graphene (?13.1) and its multilayers is much larger than rGO (?4.4), while GO (?1.5) has the lowest quenching efficiency, which suggests that the graphitic structure is an important factor for quenching the fluorescence of QDs. It was also revealed that the QF of graphene is not strongly dependent on its thicknesses.

Guo, Xi Tao; Hua Ni, Zhen, E-mail: zhni@seu.edu.cn; Yan Nan, Hai; Hui Wang, Wen [Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189 (China)] [Department of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing 211189 (China); Yan Liao, Chun [Physics Department, National Photoelectric Technology and Functional Materials and Application of Science and Technology International Cooperation Base, Northwest University, Xi'an 710069 (China)] [Physics Department, National Photoelectric Technology and Functional Materials and Application of Science and Technology International Cooperation Base, Northwest University, Xi'an 710069 (China); Zhang, Yan; Wei Zhao, Wei [Jiangsu Key Laboratory for Design and Fabrication of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189 (China)] [Jiangsu Key Laboratory for Design and Fabrication of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189 (China)

2013-11-11T23:59:59.000Z

268

Quantum dots in bio-imaging: Revolution by the small  

SciTech Connect (OSTI)

Visual analysis of biomolecules is an integral avenue of basic and applied biological research. It has been widely carried out by tagging of nucleotides and proteins with traditional fluorophores that are limited in their application by features such as photobleaching, spectral overlaps, and operational difficulties. Quantum dots (QDs) are emerging as a superior alternative and are poised to change the world of bio-imaging and further its applications in basic and applied biology. The interdisciplinary field of nanobiotechnology is experiencing a revolution and QDs as an enabling technology have become a harbinger of this hybrid field. Within a decade, research on QDs has evolved from being a pure science subject to the one with high-end commercial applications.

Arya, Harinder [Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Kaul, Zeenia [Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Wadhwa, Renu [Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Taira, Kazunari [Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Hirano, Takashi [Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, 7 Ibaraki 305-8562 (Japan); Kaul, Sunil C. [Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan)]. E-mail: s-kaul@aist.go.jp

2005-04-22T23:59:59.000Z

269

Valley pair qubits in double quantum dots of gapped graphene  

E-Print Network [OSTI]

The rise of graphene opens a new door to qubit implementation, as discussed in the recent proposal of valley pair qubits in double quantum dots of gapped graphene (Wu et al., arXiv: 1104.0443 [cond-mat.mes-hall]). The work here presents the comprehensive theory underlying the proposal. It discusses the interaction of electrons with external magnetic and electric fields in such structures. Specifically, it examines a strong, unique mechanism, i.e., the analogue of the 1st-order relativistic effect in gapped graphene. This mechanism is state mixing free and allows, together with the electrically tunable exchange coupling, a fast, all-electric manipulation of qubits via electric gates, in the time scale of ns. The work also looks into the issue of fault tolerance in a typical case, yielding at 10oK a long qubit coherence time (~O(ms)).

G. Y. Wu; N. -Y. Lue; L. Chang

2011-07-03T23:59:59.000Z

270

Ultra-low density InAs quantum dots  

SciTech Connect (OSTI)

We show that InAs quantum dots (QDs) can be grown by molecular beam epitaxy (MBE) with an ultralow density of sin 10{sup 7} cm{sup -2} without any preliminary or post-growth surface treatment. The strain-induced QD formation proceeds via the standard Stranski-Krastanow mechanism, where the InAs coverage is decreased to 1.3-1.5 monolayers (MLs). By using off-cut GaAs (100) substrates, we facilitate the island nucleation in this subcritical coverage range without any growth interruption. The QD density dependences on the InAs coverage are studied by photoluminescence, atomic force microscopy, transmission electron microscopy, and are well reproduced by the universal double exponential shapes. This method enables the fabrication of InAs QDs with controllable density in the range 10{sup 7}-10{sup 8} cm{sup -2}, exhibiting bright photoluminescence.

Dubrovskii, V. G., E-mail: dubrovskii@mail.ioffe.ru; Cirlin, G. E. [St. Petersburg Academic University Russian Academy of Sciences (Russian Federation)] [St. Petersburg Academic University Russian Academy of Sciences (Russian Federation); Brunkov, P. A. [Ioffe Physical Technical Institute Russian Academy of Sciences (Russian Federation)] [Ioffe Physical Technical Institute Russian Academy of Sciences (Russian Federation); Perimetti, U.; Akopyan, N. [Delft University of Technology, Quantum Transport, Kavli Institute of Nanoscience (Netherlands)] [Delft University of Technology, Quantum Transport, Kavli Institute of Nanoscience (Netherlands)

2013-10-15T23:59:59.000Z

271

Development of low-temperature solution-processed colloidal quantum dot-based solar cells  

E-Print Network [OSTI]

Solution-processed solar cells incorporating organic semiconductors and inorganic colloidal quantum dots (QDs) are potential alternatives to conventional solar cells fabricated via vacuum or high-temperature sintering ...

Chang, Liang-Yi, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

272

Efficient light emitting devices utilizing CdSe(ZnS) quantum dots in organic host matrices  

E-Print Network [OSTI]

We demonstrate efficient electroluminescence from thin film structures containing core-shell CdSe(ZnS) quantum dots dispersed in molecular organic host materials. In the most efficient devices, excitons are created on the ...

Coe-Sullivan, Seth (Seth Alexander)

2002-01-01T23:59:59.000Z

273

Luminescent, quantum dot-based anti-reflective coatings for crystalline silicon photovoltaics  

E-Print Network [OSTI]

This thesis demonstrates and evaluates the potential application of luminescent quantum dot/polymer solutions on crystalline silicon photovoltaics. After spin coating the QD/polymer onto silicon photodiodes, an increase ...

Bruer, Garrett (Garrett A.)

2010-01-01T23:59:59.000Z

274

Ligand Mediated Surface Reconstruction of Photoluminescent CdTe Quantum Dots.  

E-Print Network [OSTI]

??Enhancement of photoluminescence (PL) is observed for light-shielded dodecylamine-capped colloidal CdTe quantum dots (CdTe/DDA QDs) dispersed in toluene after washing and recapping. The PL quantum… (more)

Onnink, A.J.

2013-01-01T23:59:59.000Z

275

Compact biocompatible quantum dots via RAFT-mediated synthesis of imidazole-based random copolymer ligand  

E-Print Network [OSTI]

We present a new class of polymeric ligands for quantum dot (QD) water solubilization to yield biocompatible and derivatizable QDs with compact size (10?12 nm diameter), high quantum yields (>50%), excellent stability ...

Liu, Wenhao

276

Colloidal quantum-dot light-emitting diodes with metal-oxide charge  

E-Print Network [OSTI]

across the pixel area, and fabrication required the specialized deposition technique of energy-neutral over previously reported structures8,10 . Previous efforts at building colloidal quantum-dot (QD) LEDs concentrations and energy-band

277

Exchange Control of Nuclear Spin Diffusion in a Double Quantum Dot  

E-Print Network [OSTI]

The influence of gate-controlled two-electron exchange on the relaxation of nuclear polarization in small ensembles (N?10[superscript 6]) of nuclear spins is examined in a GaAs double quantum dot system. Waiting in the ...

Reilly, D. J.

278

Nuclear spin dynamics in double quantum dots: Fixed points, transients, and intermittency  

E-Print Network [OSTI]

Transport through spin-blockaded quantum dots provides a means for electrical control and detection of nuclear spin dynamics in the host material. Although such experiments have become increasingly popular in recent years, ...

Rudner, M. S.

279

Lateral heterojunction photodetector consisting of molecular organic and colloidal quantum dot thin films  

E-Print Network [OSTI]

exception being the dye- sensitized solar cell.3 Owing to its unique geometry, the present device also and that is sensitized across visible wavelengths by a thin film of colloidal CdSe nanocrystal quantum dots QDs . High

280

E-Print Network 3.0 - anisn format dot Sample Search Results  

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

the ANISN (Ref. 8), DOT (Ref. 9), and TWOTRAN (Ref. 10) codes. The continuous energy VIM Monte Carlo code... in Sec. VIII a r e derived from three- dimensional calculations....

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Gain dynamics of quantum dot devices for dual-state operation  

SciTech Connect (OSTI)

Ground state gain dynamics of In(Ga)As-quantum dot excited state lasers are investigated via single-color ultrafast pump-probe spectroscopy below and above lasing threshold. Two-color pump-probe experiments are used to localize lasing and non-lasing quantum dots within the inhomogeneously broadened ground state. Single-color results yield similar gain recovery rates of the ground state for lasing and non-lasing quantum dots decreasing from 6 ps to 2 ps with increasing injection current. We find that ground state gain dynamics are influenced solely by the injection current and unaffected by laser operation of the excited state. This independence is promising for dual-state operation schemes in quantum dot based optoelectronic devices.

Kaptan, Y., E-mail: yuecel.kaptan@physik.tu-berlin.de; Herzog, B.; Kolarczik, M.; Owschimikow, N.; Woggon, U. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin (Germany); Schmeckebier, H.; Arsenijevi?, D.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Berlin (Germany); Mikhelashvili, V.; Eisenstein, G. [Technion Institute of Technology, Faculty of Electrical Engineering, Haifa (Israel)

2014-06-30T23:59:59.000Z

282

The physics and chemistry of transport in CdSe quantum dot solids  

E-Print Network [OSTI]

Semiconductor quantum dots (QDs) have tunable opto-electronic properties and can be chemically synthesized and manipulated with ease, making them a promising novel material for many diverse applications. An understanding ...

Jarosz, Mirna, 1981-

2004-01-01T23:59:59.000Z

283

Electrical excitation of colloidally synthesized quantum dots in metal oxide structures  

E-Print Network [OSTI]

This thesis develops methods for integrating colloidally synthesized quantum dots (QDs) and metal oxides in optoelectronic devices, presents three distinct light emitting devices (LEDs) with metal oxides surrounding a QD ...

Wood, Vanessa Claire

2010-01-01T23:59:59.000Z

284

InGaAs Quantum Dots Coupled to a Reservoir of Nonequilibrium Free Carriers  

E-Print Network [OSTI]

We discuss the impact of a 2D-charged carrier reservoir for high-speed optical amplification and modulated lasing in quantum dot (QD)-based devices by testing the amplification of short trains of high power, femtosecond ...

Laemmlin, Matthias

285

E-Print Network 3.0 - alloy quantum dots Sample Search Results  

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

a dilute nitride: InAsNGaAsSb, GaInAsInP and In... . QUANTUM DOT INTERMEDIATE BAND SOLAR CELL MATERIAL SYSTEMS WITH NEGLIGIBLE VALENCE BAND OFFSETS Michael Y... ABSTRACT In...

286

Developing an array of site-controlled pyramidal quantum dots emitting polarization-entangled photons  

SciTech Connect (OSTI)

We present a site-controlled, highly symmetric quantum dot system with a density of at least 15 % of polarization-entangled photon emitters. Fidelity values of the entangled state as high as 0.721±0.043 were found.

Juska, G.; Dimastrodonato, V.; Mereni, L. O.; Gocalinska, A.; Pelucchi, E. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

2013-12-04T23:59:59.000Z

287

Determination of energy scales in few-electron double quantum dots  

SciTech Connect (OSTI)

The capacitive couplings between gate-defined quantum dots and their gates vary considerably as a function of applied gate voltages. The conversion between gate voltages and the relevant energy scales is usually performed in a regime of rather symmetric dot-lead tunnel couplings strong enough to allow direct transport measurements. Unfortunately, this standard procedure fails for weak and possibly asymmetric tunnel couplings, often the case in realistic devices. We have developed methods to determine the gate voltage to energy conversion accurately in the different regimes of dot-lead tunnel couplings and demonstrate strong variations of the conversion factors. Our concepts can easily be extended to triple quantum dots or even larger arrays.

Taubert, D.; Ludwig, S. [Center for NanoScience and Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Schuh, D. [Institut fuer Experimentelle Physik, Universitaet Regensburg, D-93040 Regensburg (Germany); Wegscheider, W. [Laboratory for Solid State Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland)

2011-12-15T23:59:59.000Z

288

Quantum Dots Promise to Significantly Boost Solar Cell Efficiencies (Fact Sheet)  

SciTech Connect (OSTI)

In the search for a third generation of solar-cell technologies, a leading candidate is the use of 'quantum dots' -- tiny spheres of semiconductor material measuring only about 2-10 billionths of a meter in diameter. Quantum dots have the potential to dramatically increase the efficiency of converting sunlight into energy -- perhaps even doubling it in some devices -- because of their ability to generate more than one bound electron-hole pair, or exciton, per incoming photon. NREL has produced quantum dots using colloidal suspensions; then, using molecular self-assembly, they have been fabricated into the first-ever quantum-dot solar cells. While these devices operate with only 4.4% efficiency, they demonstrate the capability for low-cost manufacturing.

Not Available

2013-08-01T23:59:59.000Z

289

Efficiency loss mechanisms in colloidal quantum-dot light-emitting diodes  

E-Print Network [OSTI]

Saturated and tunable emission colors make colloidal quantum-dot light-emitting diodes (QD-LEDs) interesting for the next generation of display and lighting technologies. However, there still remain various hurdles to the ...

Shirasaki, Yasuhiro

2013-01-01T23:59:59.000Z

290

TxDOT Best Practices Model and Implementation Guide for Advance Planning Risk Analysis for  

E-Print Network [OSTI]

0-5478-P2 TxDOT Best Practices Model and Implementation Guide for Advance Planning Risk Analysis?....................................................................................................1 1.2 Advance Planning Risk Analysis...........................................................................................................11 3.4 Philosophy of Use

Texas at Austin, University of

291

Two-Photon Oxygen Sensing with Quantum Dot-Porphyrin Conjugates  

E-Print Network [OSTI]

Supramolecular assemblies of a quantum dot (QD) associated to palladium(II) porphyrins have been developed to detect oxygen (pO[subscript 2]) in organic solvents. Palladium porphyrins are sensitive in the 0–160 Torr range, ...

Lemon, Christopher M.

292

Narrow-Band Absorption-Enhanced Quantum Dot/J-Aggregate Conjugates  

E-Print Network [OSTI]

We report narrow-band absorption enhancement of semiconductor nanocrystals via Förster resonance energy transfer from cyanine J-aggregates. These J-aggregated dyes associate electrostatically with short quantum-dot (QD) ...

Walker, Brian J.

293

(In,Mn)As quantum dots: Molecular-beam epitaxy and optical properties  

SciTech Connect (OSTI)

Self-assembled (In,Mn)As quantum dots are synthesized by molecular-beam epitaxy on GaAs (001) substrates. The experimental results obtained by transmission electron microscopy show that doping of the central part of the quantum dots with Mn does not bring about the formation of structural defects. The optical properties of the samples, including those in external magnetic fields, are studied.

Bouravleuv, A. D., E-mail: bour@mail.ioffe.ru; Nevedomskii, V. N. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Ubyivovk, E. V. [St. Petersburg State University (Russian Federation)] [St. Petersburg State University (Russian Federation); Sapega, V. F. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Khrebtov, A. I. [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation)] [St. Petersburg Academic University, Nanotechnology Research and Education Centre (Russian Federation); Samsonenko, Yu. B.; Cirlin, G. E.; Ustinov, V. M. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-08-15T23:59:59.000Z

294

Regulatory compliance guide for DOT-7A type A packaging design  

SciTech Connect (OSTI)

The purpose of this guide is to provide instruction for assuring that the regulatory design requirements for a DOT-7A Type A packaging are met. This guide also supports the testing and evaluation activities that are performed on new packaging designs by a DOE-approved test facility through the DOE`s DOT-7A Test Program. This Guide was updated to incorporate regulatory changes implemented by HM-169A (49 CFR, `Transportation`).

Kelly, D.L.

1996-06-04T23:59:59.000Z

295

Two photon luminescence from quantum dots using broad and narrowband ultrafast laser pulses  

E-Print Network [OSTI]

TWO PHOTON LUMINESCENCE FROM QUANTUM DOTS USING BROAD AND NARROWBAND ULTRAFAST LASER PULSES A Thesis by HARIBHASKAR BALASUBRAMANIAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 2007 Major Subject: Biomedical Engineering TWO PHOTON LUMINESCENCE FROM QUANTUM DOTS USING BROAD AND NARROWBAND ULTRAFAST LASER PULSES A Thesis by HARIBHASKAR...

Balasubramanian, Haribhaskar

2008-10-10T23:59:59.000Z

296

Off-resonant coupling between a single quantum dot and a nanobeam photonic crystal cavity  

E-Print Network [OSTI]

We demonstrate off-resonant coupling between a single quantum dot and a nanobeam photonic crystal cavity, under resonant excitation of the quantum dot or the cavity. These results are consistent with previous descriptions of off-resonant coupling as an incoherent phonon-mediated process. The extension of this phenomenon to a nanobeam photonic crystal cavity presents interesting possibilities for coherent control of this interaction by tailoring the phonon density of states.

Armand Rundquist; Arka Majumdar; Jelena Vuckovic

2011-10-05T23:59:59.000Z

297

Ultrafast photon-photon interaction in a strongly coupled quantum dot-cavity system  

E-Print Network [OSTI]

We study dynamics of the interaction between two weak light beams mediated by a strongly coupled quantum dot-photonic crystal cavity system. First, we perform all optical switching of a weak continuous-wave signal with a pulsed control beam, and then perform switching between two pulsed beams (40ps pulses) at the single photon level. Our results show that the quantum dot-nanocavity system creates strong, controllable interactions at the single photon level.

Dirk Englund; Arka Majumdar; Michal Bajcsy; Andrei Faraon; Pierre Petroff; Jelena vuckovic

2011-07-14T23:59:59.000Z

298

Effect of quantum dot position and background doping on the performance of quantum dot enhanced GaAs solar cells  

SciTech Connect (OSTI)

The effect of the position of InAs quantum dots (QD) within the intrinsic region of pin-GaAs solar cells is reported. Simulations suggest placing the QDs in regions of reduced recombination enables a recovery of open-circuit voltage (V{sub OC}). Devices with the QDs placed in the center and near the doped regions of a pin-GaAs solar cell were experimentally investigated. While the V{sub OC} of the emitter-shifted device was degraded, the center and base-shifted devices exhibited V{sub OC} comparable to the baseline structure. This asymmetry is attributed to background doping which modifies the recombination profile and must be considered when optimizing QD placement.

Driscoll, Kristina, E-mail: kmdsps@rit.edu; Bennett, Mitchell F.; Polly, Stephen J.; Forbes, David V.; Hubbard, Seth M., E-mail: smhsps@rit.edu [NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, New York (United States)

2014-01-13T23:59:59.000Z

299

Engineering of quantum dot photon sources via electro-elastic fields  

E-Print Network [OSTI]

The possibility to generate and manipulate non-classical light using the tools of mature semiconductor technology carries great promise for the implementation of quantum communication science. This is indeed one of the main driving forces behind ongoing research on the study of semiconductor quantum dots. Often referred to as artificial atoms, quantum dots can generate single and entangled photons on demand and, unlike their natural counterpart, can be easily integrated into well-established optoelectronic devices. However, the inherent random nature of the quantum dot growth processes results in a lack of control of their emission properties. This represents a major roadblock towards the exploitation of these quantum emitters in the foreseen applications. This chapter describes a novel class of quantum dot devices that uses the combined action of strain and electric fields to reshape the emission properties of single quantum dots. The resulting electro-elastic fields allow for control of emission and binding energies, charge states, and energy level splittings and are suitable to correct for the quantum dot structural asymmetries that usually prevent these semiconductor nanostructures from emitting polarization-entangled photons. Key experiments in this field are presented and future directions are discussed.

Rinaldo Trotta; Armando Rastelli

2015-03-01T23:59:59.000Z

300

Variational transition state theory  

SciTech Connect (OSTI)

This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.

Truhlar, D.G. [Univ. of Minnesota, Minneapolis (United States)

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

TRANSITION STRATEGIES Sig Gronich  

E-Print Network [OSTI]

Options. ·Natural Gas Hydrogen · Biomass Hydrogen ·Distributed Coal / IGCC Hydrogen · Compressed Gas special attention to the transition to a nascent hydrogen economy · Analyze cost goals and Liquid Storage · Electrolysis · Compressed Gas Delivery · Cold Gas Delivery and Liquid Delivery · Co

302

Transition Implementation Guide  

Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

This Guide was prepared to aid in the development, planning, and implementation of requirements and activities during the transition phase at Department of Energy (DOE) facilities that have been declared or are forecast to become excess to any future mission requirements.

2001-04-24T23:59:59.000Z

303

Size dependent optical properties of Si quantum dots in Si-rich nitride/Si{sub 3}N{sub 4} superlattice synthesized by magnetron sputtering  

SciTech Connect (OSTI)

A spectroscopic ellipsometry compatible approach is reported for the optical study of Si quantum dots (QDs) in Si-rich nitride/silicon nitride (SRN/Si{sub 3}N{sub 4}) superlattice, which based on Tauc-Lorentz model and Bruggeman effective medium approximation. It is shown that the optical constants and dielectric functions of Si QDs are strongly size dependent. The suppressed imaginary dielectric function of Si QDs exhibits a single broad peak analogous to amorphous Si, which centered between the transition energies E{sub 1} and E{sub 2} of bulk crystalline Si and blue shifted toward E{sub 2} as the QD size reduced. A bandgap expansion observed by the TL model when the size of Si QD reduced is in good agreement with the PL measurement. The bandgap expansion with the reduction of Si QD size is well supported by the first-principles calculations based on quantum confinement.

So, Yong-Heng; Huang, Shujuan; Conibeer, Gavin; Green, Martin A. [ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney, New South Wales 2052 (Australia); Gentle, Angus [Physics and Advanced Materials, University of Technology Sydney, P. O. Box 123, Broadway, New South Wales 2007 (Australia)

2011-03-15T23:59:59.000Z

304

Effects of capping on GaN quantum dots deposited on Al{sub 0.5}Ga{sub 0.5}N by molecular beam epitaxy  

SciTech Connect (OSTI)

The impact of the capping process on the structural and morphological properties of GaN quantum dots (QDs) grown on fully relaxed Al{sub 0.5}Ga{sub 0.5}N templates was studied by transmission electron microscopy. A morphological transition between the surface QDs, which have a pyramidal shape, and the buried ones, which have a truncated pyramid shape, is evidenced. This shape evolution is accompanied by a volume change: buried QDs are bigger than surface ones. Furthermore a phase separation into Al{sub 0.5}Ga{sub 0.5}N barriers was observed in the close vicinity of buried QDs. As a result, the buried QDs were found to be connected with the nearest neighbors by thin Ga-rich zones, whereas Al-rich zones are situated above the QDs.

Korytov, M. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France) and University of Nice Sophia-Antipolis, Parc Valrose, 06103 Nice (France); Benaissa, M. [CNRST, angle Allal-Fassi/FAR, Madinat al-irfane, 10000 Rabat (Morocco); Brault, J.; Vennegues, P. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Huault, T. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne, France and RIBER S.A., 31 rue Casimir Perier, BP 70083, 95873 Bezons Cedex (France); Neisius, T. [CP2M, Faculte Saint Jerome, 13397 Marseille Cedex 20 (France)

2009-04-06T23:59:59.000Z

305

Electrically driven single photon emission from a CdSe/ZnSSe single quantum dot at 200?K  

SciTech Connect (OSTI)

High temperature operation of an electrically driven single photon emitter based on a single epitaxial quantum dot is reported. CdSe/ZnSSe/MgS quantum dots are embedded into a p-i-n diode architecture providing almost background free excitonic and biexcitonic electroluminescence from individual quantum dots through apertures in the top contacts. Clear antibunching with g{sup 2}(??=?0)?=?0.28?±?0.20 can be tracked up to T?=?200?K, representing the highest temperature for electrically triggered single photon emission from a single quantum dot device.

Quitsch, Wolf; Kümmell, Tilmar; Bacher, Gerd [Werkstoffe der Elektrotechnik and CENIDE, Universität Duisburg-Essen, Bismarckstraße 81, 47057 Duisburg (Germany); Gust, Arne; Kruse, Carsten; Hommel, Detlef [Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28334 Bremen (Germany)

2014-09-01T23:59:59.000Z

306

Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots  

SciTech Connect (OSTI)

We report strong heavy hole-light hole mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k{center_dot}p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.

Belhadj, T.; Amand, T.; Kunz, S.; Marie, X.; Urbaszek, B. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); Kunold, A. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); Departamento de Ciencias Basicas, UAM-A, Col. Reynosa Tamaulipas, 02200 Mexico D.F. (Mexico); Simon, C.-M. [INSA-CNRS-UPS, LPCNO, Universite de Toulouse, 135 Av. Rangueil, 31077 Toulouse (France); CNRS-UPS, LCAR, IRSAMC, Universite de Toulouse, 31062 Toulouse (France); Kuroda, T.; Abbarchi, M.; Mano, T.; Sakoda, K. [National Institute for Material Science, Namiki 1-1, Tsukuba 305-0044 (Japan)

2010-08-02T23:59:59.000Z

307

In vitro adrenal bioactivation and effects on steroid metabolism of DDT, PCBs and their metabolites in the gray seal (Halichoerus grypus)  

SciTech Connect (OSTI)

The irreversible binding of the DDT metabolites o,p[prime]-DDD [2-(2-chlorophenyl)-2(4-chlorophenyl)-1,1-dichloroethane] and MeSO[sub 2]-DDE [3-methylsulfonyl-2,2-bis(4-chlorophenyl)-1,1-dichloroethene], as well as their potential to inhibit mitochondrial steroid 11[beta]-hydroxylation in the gray seal adrenal gland, was studied. The adrenal bioactivated both o,p[prime]-DDD and MeSO[sub 2[minus

Lund, B.O. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Pharmacology and Toxicology)

1994-06-01T23:59:59.000Z

308

Effects of boat traffic on the behavior of gray whales, Eschrichtius robustus, in Bahia Magdalena, Baja California Sur, Mexico: a bioacoustic assessment  

E-Print Network [OSTI]

functions, whales are dependent on acoustic signaling for spacing (positioning), attracting conspecifics (advertising reproductive status), and alerting against danger (predators) (Reeves 1977). Whales must be able to accommodate to the ambient noise... that prevails at their specific location, so that their sounds and signals are receivable, Dahlheim (1987) suggested that gray whales occupy specific acoustic niches related to specific ambient noise of these lagoons. Survival probabilities of any species...

Ollervides, Francisco

1997-01-01T23:59:59.000Z

309

Transition-fault test generation  

E-Print Network [OSTI]

. One way to detect these timing defects is to apply test patterns to the integrated circuit that are generated using the transition-fault model. Unfortunately, industry's current transition-fault test generation schemes produce test sets that are too...

Cobb, Bradley Douglas

2013-02-22T23:59:59.000Z

310

Effect of shells on photoluminescence of aqueous CdTe quantum dots  

SciTech Connect (OSTI)

Graphical abstract: Size-tunable CdTe coated with several shells using an aqueous solution synthesis. CdTe/CdS/ZnS quantum dots exhibited high PL efficiency up to 80% which implies the promising applications for biomedical labeling. - Highlights: • CdTe quantum dots were fabricated using an aqueous synthesis. • CdS, ZnS, and CdS/ZnS shells were subsequently deposited on CdTe cores. • Outer ZnS shells provide an efficient confinement of electron and hole inside the QDs. • Inside CdS shells can reduce the strain on the QDs. • Aqueous CdTe/CdS/ZnS QDs exhibited high stability and photoluminescence efficiency of 80%. - Abstract: CdTe cores with various sizes were fabricated in aqueous solutions. Inorganic shells including CdS, ZnS, and CdS/ZnS were subsequently deposited on the cores through a similar aqueous procedure to investigate the effect of shells on the photoluminescence properties of the cores. In the case of CdTe/CdS/ZnS quantum dots, the outer ZnS shell provides an efficient confinement of electron and hole wavefunctions inside the quantum dots, while the middle CdS shell sandwiched between the CdTe core and ZnS shell can be introduced to obviously reduce the strain on the quantum dots because the lattice parameters of CdS is situated at the intermediate-level between those of CdTe and ZnS. In comparison with CdTe/ZnS core–shell quantum dots, the as-prepared water-soluble CdTe/CdS/ZnS quantum dots in our case can exhibit high photochemical stability and photoluminescence efficiency up to 80% in an aqueous solution, which implies the promising applications in the field of biomedical labeling.

Yuan, Zhimin; Yang, Ping, E-mail: mse_yangp@ujn.edu.cn

2013-07-15T23:59:59.000Z

311

Using quantum dots to tag subsurface damage in lapped and polished glass samples  

SciTech Connect (OSTI)

Grinding, lapping, and polishing are finishing processes used to achieve critical surface parameters in a variety of precision optical and electronic components. As these processes remove material from the surface through mechanical and chemical interactions, they may induce a damaged layer of cracks, voids, and stressed material below the surface. This subsurface damage (SSD) can degrade the performance of a final product by creating optical aberrations due to diffraction, premature failure in oscillating components, and a reduction in the laser induced damage threshold of high energy optics. As these defects lie beneath the surface, they are difficult to detect, and while many methods are available to detect SSD, they can have notable limitations regarding sample size and type, preparation time, or can be destructive in nature. The authors tested a nondestructive method for assessing SSD that consisted of tagging the abrasive slurries used in lapping and polishing with quantum dots (nano-sized fluorescent particles). Subsequent detection of fluorescence on the processed surface is hypothesized to indicate SSD. Quantum dots that were introduced to glass surfaces during the lapping process were retained through subsequent polishing and cleaning processes. The quantum dots were successfully imaged by both wide field and confocal fluorescence microscopy techniques. The detected fluorescence highlighted features that were not observable with optical or interferometric microscopy. Atomic force microscopy and additional confocal microscope analysis indicate that the dots are firmly embedded in the surface but do not appear to travel deep into fractures beneath the surface. Etching of the samples exhibiting fluorescence confirmed that SSD existed. SSD-free samples exposed to quantum dots did not retain the dots in their surfaces, even when polished in the presence of quantum dots.

Williams, Wesley B.; Mullany, Brigid A.; Parker, Wesley C.; Moyer, Patrick J.; Randles, Mark H.

2009-09-20T23:59:59.000Z

312

Refrigerants in Transition  

E-Print Network [OSTI]

.E. Senior Engineer The Hartford Steam Boiler Inspection and Insurance Company Hartford,. Connecticut ABSTRACT The massive growth of air conditioning and refrigeration has been a direct result of the development of a class of chemicals called fluorocarbons..., Gordon, "Forty Years Research on Atmospheric Ozone at Oxford: A !Iistory," Applied Optics, March t968, pp. 387-405. 4. Downing, R., "Development of Chloro fluorocarbon Refrigerants," CFCs: Time of Transition, ASHRAE Publication, Atlanta, GA, 1989...

Stouppe, D. E.

313

The energy transition Gerald Leach  

E-Print Network [OSTI]

The energy transition Gerald Leach The paper considers the substitution of tradition. The In the context of energy policy and planning, the paper concludes with a review of the reasons why transition. In the IS THE TRANSITION HAPPENING? poorest developing countries biomass fuels account for 60-95% of total energy use

Kammen, Daniel M.

314

Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Preliminary Evaluation Results  

SciTech Connect (OSTI)

This report provides an evaluation of three prototype fuel cell-powered transit buses operating at AC Transit in Oakland, California, and six baseline diesel buses similar in design to the fuel cell buses.

Chandler, K.; Eudy, L.

2007-03-01T23:59:59.000Z

315

PROPERTIES OF UMBRAL DOTS FROM STRAY LIGHT CORRECTED HINODE FILTERGRAMS  

SciTech Connect (OSTI)

High-resolution blue continuum filtergrams from Hinode are employed to study the umbral fine structure of a regular unipolar sunspot. The removal of scattered light from the images increases the rms contrast by a factor of 1.45 on average. Improvement in image contrast renders identification of short filamentary structures resembling penumbrae that are well separated from the umbra-penumbra boundary and comprise bright filaments/grains flanking dark filaments. Such fine structures were recently detected from ground-based telescopes and have now been observed with Hinode. A multi-level tracking algorithm was used to identify umbral dots (UDs) in both the uncorrected and corrected images and to track them in time. The distribution of the values describing the photometric and geometric properties of UDs is more easily affected by the presence of stray light while it is less severe in the case of kinematic properties. Statistically, UDs exhibit a peak intensity, effective diameter, lifetime, horizontal speed, and a trajectory length of 0.29I{sub QS}, 272 km, 8.4 minutes, 0.45 km s{sup -1}, and 221 km, respectively. The 2 hr 20 minute time sequence depicts several locations where UDs tend to appear and disappear repeatedly with various time intervals. The correction for scattered light in the Hinode filtergrams facilitates photometry of umbral fine structure, which can be related to results obtained from larger telescopes and numerical simulations.

Louis, Rohan E.; Mathew, Shibu K.; Bayanna, A. Raja [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Badi Road, Udaipur, Rajasthan 313004 (India); Rubio, Luis R. Bellot [Instituto de Astrofisica de Andalucia (CSIC), Apartado de Correos 3004, 18080 Granada (Spain); Ichimoto, Kiyoshi [Kwasan and Hida Observatories, Kyoto University, Yamashina-ku, Kyoto 607-8417 (Japan); Ravindra, B., E-mail: eugene@prl.res.in [Indian Institute of Astrophysics, II Block, Koramangla, Bangalore 560034 (India)

2012-06-20T23:59:59.000Z

316

Ultrafast dynamics of strongly coupled quantum dot-nanocavity systems  

E-Print Network [OSTI]

We investigate the influence of exciton-phonon coupling on the dynamics of a strongly coupled quantum dot-photonic crystal cavity system and explore the effects of this interaction on different schemes for non-classical light generation. By performing time-resolved measurements, we map out the detuning-dependent polariton lifetime and extract the spectrum of the polariton-to-phonon coupling. Photon-blockade experiments are presented for different pulse-length and detuning conditions that are in very good agreement with quantum-optical simulations; we demonstrate that achieving high-fidelity photon blockade requires an intricate understanding of this parameter space. Furthermore, we show that detuned photon blockade, which is more efficient than resonant photon blockade, is also more dramatically affected by phonons. Finally, we achieve coherent control of the polariton states of a strongly coupled system and demonstrate that their efficient coupling to phonons can be exploited for novel concepts in high-fidelity single photon generation.

Kai Müller; Kevin A. Fischer; Armand Rundquist; Constantin Dory; Konstantinos G. Lagoudakis; Tomas Sarmiento; Victoria Borish; Yousif A. Kelaita; Jelena Vu?kovi?

2015-03-18T23:59:59.000Z

317

arXiv:cond-mat/0005262v116May2000 Spin transitions in a small Si quantum dot  

E-Print Network [OSTI]

during every tunneling event. PACS numbers: 73.23.Hk, 85.30.Wx, 85.30.Vw, 85.30.Tv, 71.70.Ej The spin, the Coulomb blockade is lifted in the corresponding conduction val- ley at low temperatures. Indeed, valleys

318

Study of valence-band intersublevel transitions in InAs/GaAs quantum dots-in-well infrared photodetectors  

E-Print Network [OSTI]

://scitation.aip.org/content/aip/journal/apl/104/17?ver=pdfcov Published by the AIP Publishing Articles you may be interested in An intermediate-band

Matsik, Steven G.

319

The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures  

SciTech Connect (OSTI)

Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling structures. Large-area deployment of such structures is useful for energy selective contacts but such configuration is susceptible to structural disorders. In this work, the transport properties of quantum-dot-based wide-area resonant tunneling structures, subject to realistic disorder mechanisms, are studied. Positional variations of the quantum dots are shown to reduce the resonant transmission peaks while size variations in the device are shown to reduce as well as broaden the peaks. Increased quantum dot size distribution also results in a peak shift to lower energy which is attributed to large dots dominating transmission. A decrease in barrier thickness reduces the relative peak height while the overall transmission increases dramatically due to lower “series resistance.” While any shift away from ideality can be intuitively expected to reduce the resonance peak, quantification allows better understanding of the tolerances required for fabricating structures based on resonant tunneling phenomena/.

Puthen-Veettil, B., E-mail: b.puthen-veettil@unsw.edu.au; Patterson, R.; König, D.; Conibeer, G.; Green, M. A. [Australian Centre for Advanced Photovoltaics, UNSW, Sydney 2052 (Australia)

2014-10-28T23:59:59.000Z

320

Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes  

SciTech Connect (OSTI)

We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)] [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2013-01-28T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Biochemical and behavioral effects of phospholipase A/sub 2/ and morphine microinjections in the periaqueductal gray of the rat  

SciTech Connect (OSTI)

In order to characterize the in vivo action of phospholipase A/sub 2/ (PLA/sub 2/) on opiate receptors and opiate-induced behaviors, the effects of injections of PLA/sub 2/ into the periaqueductal gray region (PAG) of the rat were assessed on free fatty acid (FFA) release, opiate-binding levels, and morphine-induced behaviors. Rats received bilateral PAG injections of 2 ..mu..g of PLA/sub 2/ while anesthetized. One hour later, regions around the cannulae tracts in PLA/sub 2/-treated rats contained over 2.5 times more FFA than saline-injected controls, and /sup 3/H-dihydromorphine binding was reduced on average more than 70%. In another series of experiments, conscious rats were given 2 ..mu..g of PLA/sub 2/ prior to 10 ..mu..g of morphine through cannulae chronically implanted into the PAG. PLA/sub 2/ did not significantly attenuate morphine-induced analgesia as measured by the tail-flick test to radiant heat, but did prevent the explosive motor behavior observed following morphine injections alone. PLA/sub 2/ by itself did not induce analgesia, but did cause explosive motor behavior 2 hr after the injections. Neither lysophosphatidylcholine nor trypsin resulted in motor seizures following PAG injections. It was concluded that the behavioral effects of PLA/sub 2/ result from the unique properties of the enzyme, rather than generalized membrane damage, and that the opioid sites and mechanisms that mediate analgesia are different from those associated with explosive motor behavior. 36 references, 2 figures, 2 tables.

Reichman, M.; Abood, L.G.; Costanzo, M.

1985-02-11T23:59:59.000Z

322

Transition Metal Switchable Mirror  

ScienceCinema (OSTI)

The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft. More information at: http://windows.lbl.gov/materials/chromogenics/default.htm

None

2013-05-29T23:59:59.000Z

323

Transition Metal Switchable Mirror  

ScienceCinema (OSTI)

The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft.

None

2010-01-08T23:59:59.000Z

324

FE Transition Deliverables  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergyENERGYWomentheATLANTA, GA5 &of Energy memoCity ofAugust 31,April 9,FE Transition

325

Transition Strategies: Government Options and Market Penetration...  

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

Strategies: Government Options and Market Penetration Scenarios Transition Strategies: Government Options and Market Penetration Scenarios Presentation on Transition Strategies:...

326

Double-Dot Quantum Ratchet Driven by an Independently Biased Quantum Point Contact V. S. Khrapai,1,2  

E-Print Network [OSTI]

Double-Dot Quantum Ratchet Driven by an Independently Biased Quantum Point Contact V. S. Khrapai,1 of the two quantum dots. The results are interpreted in terms of a quantum ratchet phenomenon in a DQD possessing current be- cause of broken spatial symmetry, so-called ratchets, ap- pear in a variety

Ludwig-Maximilians-Universität, München

327

Absorption spectra of CdSe-ZnS core-shell quantum dots at high photon energies : experiment and modeling  

E-Print Network [OSTI]

Absorption spectra of CdSe-ZnS core-shell quantum dots at high photon energies : experiment spectra of CdSe-ZnS core-shell quantum dot (QD) ensembles, with average core diameters ranging from 2.6 nm. In agreement with previous reports, the absorption coefficient at energies 1 eV above the effective bandgap

Ghosh, Sandip

328

Analysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp characteristics  

E-Print Network [OSTI]

injection which we term "thermal impact" , the ther- mal conductivity of the active region is estimatedAnalysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp; published online 21 September 2006 The thermal conductivity of self-organized quantum dot QD active regions

Klotzkin, David

329

Microsphere Light-Scattering Layer Assembled by ZnO Nanosheets for the Construction of High Efficiency (>5%) Quantum Dots  

E-Print Network [OSTI]

performance solar cells for sustainable energy sources to replace fossil fuels has become an urgent subject for CdS/CdSe quantum dot cosensitized solar cells (QDSCs) with a power conversion efficiency (PCE Efficiency (>5%) Quantum Dots Sensitized Solar Cells Jianjun Tian,*, Lili Lv, Xuyang Wang, Chengbin Fei

Cao, Guozhong

330

Local Agency Project Manager Checklist The steps below follow those outlined in the Mn/DOT Utility Manual. A PDF of the manual  

E-Print Network [OSTI]

Form Contact utility owners Utility Contact List available at http://www.dot.state.mn.us/utility/files/pdf/contacts/contact-utilityLocal Agency Project Manager Checklist The steps below follow those outlined in the Mn/DOT Utility Manual. A PDF of the manual and supporting documents are available at: http://www.dot.state.mn.us/utility

Minnesota, University of

331

Showcasing the research of quantum dot sensitized solar cells from Prof. J.J.Tian's and Prof. G.Z.Cao's lab,  

E-Print Network [OSTI]

. Introduction Quantum dot sensitized solar cells (QDSCs) can be regarded as a derivative of dye-sensitized solarShowcasing the research of quantum dot sensitized solar cells from Prof. J.J.Tian's and Prof. G cells A hierarchical structure of ZnO/TiO2 nanocable photoanode for quantum dot sensitized solar cells

Cao, Guozhong

332

Near-infrared peptide-coated quantum dots for small animal imaging Gopal Iyer, Jack J. Li, Fabien Pinaud, James M. Tsay, Laurent A. Bentolila, Xavier  

E-Print Network [OSTI]

Near-infrared peptide-coated quantum dots for small animal imaging Gopal Iyer, Jack J. Li, Fabien ABSTRACT We have synthesized high quality type-II CdTe/CdSe near infrared quantum dots using successive ion used a peptide coating technique on type-II and commercial near infrared quantum dots for delivery

Michalet, Xavier

333

Nuclear Spin Dynamics in Double Quantum Dots: Multi-Stability, Dynamical Polarization, Criticality and Entanglement  

E-Print Network [OSTI]

We theoretically study the nuclear spin dynamics driven by electron transport and hyperfine interaction in an electrically-defined double quantum dot (DQD) in the Pauli-blockade regime. We derive a master-equation-based framework and show that the coupled electron-nuclear system displays an instability towards the buildup of large nuclear spin polarization gradients in the two quantum dots. In the presence of such inhomogeneous magnetic fields, a quantum interference effect in the collective hyperfine coupling results in sizable nuclear spin entanglement between the two quantum dots in the steady state of the evolution. We investigate this effect using analytical and numerical techniques, and demonstrate its robustness under various types of imperfections.

Martin J. A. Schuetz; Eric M. Kessler; Lieven M. K. Vandersypen; J. Ignacio Cirac; Geza Giedke

2014-05-30T23:59:59.000Z

334

Photoinduced band filling in strongly confined colloidal PbS quantum dots  

SciTech Connect (OSTI)

Increase in continuous wave laser excitation (6?W/cm{sup 2} to 120?W/cm{sup 2}) of colloidal PbS quantum dots in the strongly quantized regime (diameters 2.0?nm and 4.7?nm) deposited on semi-insulating GaAs and glass causes a clear blue shift (0.019?eV and 0.080?eV) of the emission spectra. Proof of the applicability of a dynamic three-dimensional band filling model is the significance of the presented results and demonstrates the effective electronic coupling in quantum dot arrays similar to superlattices. The work also reveals the influence of quantum dot sizes on photo-doping effects.

Ullrich, B., E-mail: bruno@fis.unam.mx [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210 (Mexico); Ullrich Photonics LLC, Wayne, Ohio 43466 (United States); Xi, H. [Department of Physics and Astronomy, Bowling Green State University, Bowling Green, Ohio 43403-0209 (United States); Wang, J. S. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright Patterson AFB, Ohio 45433-7707 (United States)

2014-06-21T23:59:59.000Z

335

Design of quantum dot lattices in amorphous matrices by ion beam irradiation  

SciTech Connect (OSTI)

We report on the highly controllable self-assembly of semiconductor quantum dots and metallic nanoparticles in a solid amorphous matrix, induced by ion beam irradiation of an amorphous multilayer. We demonstrate experimentally and theoretically a possibility to tune the basic structural properties of the quantum dots in a wide range. Furthermore, the sizes, distances, and arrangement type of the quantum dots follow simple equations dependent on the irradiation and the multilayer properties. We present a Monte Carlo model for the simulation and prediction of the structural properties of the materials formed by this method. The presented results enable engineering and simple production of functional materials or simple devices interesting for applications in nanotechnology.

Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Jaksic, M.; Salamon, K.; Drazic, G.; Bernstorff, S.; Holy, V. [Rudjer Boskovic Institute, Bijenicka cesta 54, HR-10000 Zagreb (Croatia); Institute of Physics, Bijenicka cesta 46, HR-10000 Zagreb (Croatia); Jozef Stefan Institute, Jamova 39, SLO-1000 Ljubljana (Slovenia); Sincrotrone Trieste, I-34149 Basovizza (Italy); Charles University in Prague, CZ-12116 Prague (Czech Republic)

2011-10-15T23:59:59.000Z

336

High-brightness single photon source from a quantum dot in a directional-emission nanocavity  

E-Print Network [OSTI]

We analyze a single photon source consisting of an InAs quantum dot coupled to a directional-emission photonic crystal (PC) cavity implemented in GaAs. On resonance, the dot's lifetime is reduced by more than 10 times, to 45ps. Compared to the standard three-hole defect cavity, the perturbed PC cavity design improves the collection efficiency into an objective lens (NA=0.75) by factor 6, and improves the coupling efficiency of the collected light into a single mode fiber by factor 1.9. The emission frequency is determined by the cavity mode, which is antibunched to g(2)=0.05. The cavity design also enables efficient coupling to a higher-order cavity mode for local optical excitation of cavity-coupled quantum dots.

Mitsuru Toishi; Dirk Englund; Andrei Faraon; Jelena Vuckovic

2009-04-08T23:59:59.000Z

337

Distinctive Signature of Indium Gallium Nitride Quantum Dot Lasing in Microdisks Cavities  

E-Print Network [OSTI]

Low threshold lasers realized within compact, high quality optical cavities enable a variety of nanophotonics applications. Gallium nitride (GaN) materials containing indium gallium nitride (InGaN) quantum dots and quantum wells offer an outstanding platform to study light matter interactions and realize practical devices such as efficient light emitting diodes and nanolasers. Despite progress in the growth and characterization of InGaN quantum dots, their advantages as the gain medium in low threshold lasers have not been clearly demonstrated. This work seeks to better understand the reasons for these limitations by focusing on the simpler, limited-mode microdisk cavities, and by carrying out comparisons of lasing dynamics in those cavities using varying gain media including InGaN quantum wells, fragmented quantum wells, and a combination of fragmented quantum wells with quantum dots. For each gain medium, we utilize the distinctive, high quality (Q~5500) modes of the cavities, and the change in the highest ...

Woolf, Alexander; Aharanovich, Igor; Zhu, Tongtong; Niu, Nan; Wang, Danqing; Oliver, Rachel A; Hu, Evelyn L

2014-01-01T23:59:59.000Z

338

Monolithic phosphor-free InGaN/GaN quantum dot wavelength converter white light emitting diodes  

SciTech Connect (OSTI)

We report the characteristics of phosphor-free self-organized InGaN/GaN quantum dot wavelength converter white light emitting diodes grown by plasma assisted molecular beam epitaxy. The exciting quantum dots, in which electrically injected carriers recombine, are blue-emitting and the converter dots are red-emitting. We have studied the effect of tuning the number of dot layers and the peak emission wavelength of the exciting and converter dots on the nature of the emitted white light, in terms of the chromaticity coordinates and correlated color temperature. Depending on the values of these wavelengths, color temperatures in the range of 4420–6700?K have been derived at a current density of 45?A/cm{sup 2} across multiple devices. The variation of the color temperature with change in injection current is found to be very small.

Jahangir, Shafat; Bhattacharya, Pallab, E-mail: pkb@eecs.umich.edu [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States); Pietzonka, Ines; Strassburg, Martin [OSRAM Opto Semiconductors GmbH, Leibnizstrasse 4, Regensburg (Germany)

2014-09-15T23:59:59.000Z

339

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Third...  

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

Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The prototype fuel cell bus was...

340

Alameda-Contra Costa Transit District Fuel Cell Transit Buses...  

Office of Environmental Management (EM)

Results Update This report is an update to the 2007 preliminary results report on hydrogen fuel cell and diesel buses operating at Alameda-Contra Costa Transit District....

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

AUTHORIZING THE DOT SPECIFICATION 6M PACKAGING FOR CONTINUED USE AT THE SAVANNAH RIVER SITE  

SciTech Connect (OSTI)

The U.S. Department of Transportation (DOT) Specification 6M packaging was in extensive use for more than 40 years for in-commerce shipments of Type B quantities of fissile and radioactive material (RAM) across the USA, among the Department of Energy (DOE) laboratories, and between facilities in the DOE production complex. In January 2004, the DOT Research and Special Programs Administration (RSPA) Agency issued a final rule in the Federal Register to ammend requirements in the Hazardous Materials Regulations (HMR) pertaining to the transportation of radioactive materials. The final rule became effective on October 1, 2004. One of those changes discontinued the use of the DOT specification 6M, along with other DOT specification packagings, on October 1, 2008. A main driver for the change was due to the fact that 6M specification packagings were not supported by a Safety Analysis Report for Packagings (SARP) that was compliant with Title 10 of the Code of Federal Regulations (CFR) Part 71 (10 CFR 71). The regulatory rules for the discontinued use have been edited in Title 49 of the CFR Parts 100-185, 2004 edition and thereafter. Prior to October 1, 2008, the use of the 6M within the boundaries of the Savannah River Site (SRS), called an onsite transfer, was governed by an onsite transportation document that referenced 49 CFR Parts 100-185. SRS had to develop an Onsite Safety Assessment (OSA) which was independent of 49 CFR in order to justify the continued use of the DOT Specification 6M for the transfer of radioactive material (RAM) at the SRS after October 1, 2008. This paper will discuss the methodology for and difficulties associated with authorizing the DOT Specification 6M Packaging for continued use at the Savannah River Site.

Watkins, R.; Loftin, B.; Hoang, D.

2010-03-04T23:59:59.000Z

342

Test and evaluation document for DOT Specification 7A Type A Packaging. Revision 3  

SciTech Connect (OSTI)

The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). The program is currently administered by the DOE, Office of Facility Safety Analysis, DOE/EH-32, at DOE-Headquarters (DOE-HQ) in Germantown, Maryland. This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program.

NONE

1996-01-30T23:59:59.000Z

343

Noise-Protected Gate for Six-Electron Double-Dot Qubits  

E-Print Network [OSTI]

Singlet-triplet spin qubits in six-electron double quantum dots, in moderate magnetic fields, can show superior immunity to charge noise. This immunity results from the symmetry of orbitals in the second energy shell of circular quantum dots: singlet and triplet states in this shell have identical charge distributions. Our phase-gate simulations, which include $1/f$ charge noise from fluctuating traps, show that this symmetry is most effectively exploited if the gate operation switches rapidly between sweet spots deep in the (3,3) and (4,2) charge stability regions; fidelities very close to one are predicted if subnanosecond switching can be performed.

Sebastian Mehl; David P. DiVincenzo

2014-08-05T23:59:59.000Z

344

Observation of the Kondo effect in a spin-3/2 hole quantum dot  

SciTech Connect (OSTI)

We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

Klochan, O.; Micolich, A. P.; Hamilton, A. R. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Trunov, K.; Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

2013-12-04T23:59:59.000Z

345

Fast Electrical Control of a Quantum Dot Strongly Coupled to a Nano-resonator  

E-Print Network [OSTI]

The resonance frequency of an InAs quantum dot strongly coupled to a GaAs photonic crystal cavity was electrically controlled via quantum confined Stark effect. Stark shifts up to 0.3meV were achieved using a lateral Schottky electrode that created a local depletion region at the location of the quantum dot. We report switching of a probe laser coherently coupled to the cavity up to speeds as high as 150MHz, limited by the RC constant of the transmission line. The coupling rate and the magnitude of the Stark shift with electric field were investigated while coherently probing the system.

Andrei Faraon; Arka Majumdar; Hyochul Kim; Pierre Petroff; Jelena Vuckovic

2009-06-03T23:59:59.000Z

346

Growth and optical characterization of multilayers of InGaN quantum dots  

E-Print Network [OSTI]

carried out using a two photon excitation technique employing a picosecond mode-locked Ti-sapphire laser emitting at 790 nm. Samples were mounted in a cold -finger cryostat that could be cooled down to 4.2 K and the laser was focused through a microscope... GaN quantum dots Article Type: Research Paper Section/Category: General subjects Keywords: B2. InGaN quantum dots; A1. Photoluminescence; B1. Nitrides; A3. Metal-organic vapour phase epitaxy Corresponding Author: Dr Tongtong Zhu, Ph...

Zhu, Tontong; El-Ella, Haitham; Reid, Benjamin; Holmes, Mark; Taylor, Robert; Kappers, Menno; Oliver, Rachel

2012-01-01T23:59:59.000Z

347

Spin Dynamics in Two-Dimensional Arrays of Quantum Dots with Local Ordering of Nanoclusters  

SciTech Connect (OSTI)

Electron paramagnetic resonance (EPR) is used to probe the spin dynamics in two-dimensional (2D) quantum dot (QD) arrays with local ordering of nanoclusters. A careful examination of EPR line shape, width and g-factor values allow us to attribute this signal to the electrons localized in the strain-induced potential wells in Si in the vicinity of the Ge dots. The strong orientation dependence of EPR line width is defined by changing localization degree of electrons at different magnetic field directions. The theoretical approximation of orientation dependence of EPR line width allows estimating the effective radius of electron localization, as {approx}80 nm.

Zinovieva, A. F.; Dvurechenskii, A. V.; Stepina, N. P.; Nikiforov, A. I.; Lyubin, A. S. [Institute of Semiconductor Physics, 630090 Novosibirsk, pr. Lavrentieva 13 (Russian Federation); Sobolev, N.; Carmo, M. C. [Departamento de Fisica e I3N, Universidade de Aveiro, Aveiro (Portugal)

2011-12-23T23:59:59.000Z

348

Negative differential gain in quantum dot systems: Interplay of structural properties and many-body effects  

SciTech Connect (OSTI)

The saturation behaviour of optical gain with increasing excitation density is an important factor for laser device performance. For active materials based on self-organized InGaAs/GaAs quantum dots, we study the interplay between structural properties of the quantum dots and many-body effects of excited carriers in the optical properties via a combination of tight-binding and quantum-kinetic calculations. We identify regimes where either phase-space filling or excitation-induced dephasing dominates the saturation behavior of the optical gain. The latter can lead to the emergence of a negative differential material gain.

Goldmann, E., E-mail: goldmann@itp.uni-bremen.de; Jahnke, F. [Institute for Theoretical Physics, University of Bremen, Bremen 28359 (Germany); Lorke, M.; Frauenheim, T. [Bremen Center for Computational Materials Science BCCMS, University of Bremen, Bremen 28359 (Germany)

2014-06-16T23:59:59.000Z

349

Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots  

SciTech Connect (OSTI)

In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Höfling, S.; Kamp, M. [Technische Physik, Physikalisches Institut and Wilhelm Conrad Röntgen-Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074, Würzburg (Germany); Igusa, R.; Iwamoto, S.; Arakawa, Y. [University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

2014-09-15T23:59:59.000Z

350

Sub-microsecond correlations in photoluminescence from InAs quantum dots  

E-Print Network [OSTI]

Photon correlation measurements reveal memory effects in the optical emission of single InAs quantum dots with timescales from 10 to 800 ns. With above-band optical excitation, a long-timescale negative correlation (antibunching) is observed, while with quasi-resonant excitation, a positive correlation (blinking) is observed. A simple model based on long-lived charged states is presented that approximately explains the observed behavior, providing insight into the excitation process. Such memory effects can limit the internal efficiency of light emitters based on single quantum dots, and could also be problematic for proposed quantum-computation schemes.

Charles Santori; David Fattal; Jelena Vuckovic; Glenn S. Solomon; Edo Waks; Yoshihisa Yamamoto

2003-08-16T23:59:59.000Z

351

An Efficient Source of Single Photons: A Single Quantum Dot in a Micropost Microcavity  

E-Print Network [OSTI]

We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode travelling wave is approximately 38%, which is nearly two orders of magnitude higher than for a quantum dot in bulk semiconductor material. At the same time, the probability of having more than one photon in a given pulse is reduced by a factor of seven as compared to light with Poissonian photon statistics.

Matthew Pelton; Charles Santori; Jelena Vuckovic; Bingyang Zhang; Glenn S. Solomon; Jocelyn Plant; Yoshihisa Yamamoto

2002-08-08T23:59:59.000Z

352

Cavity Quantum Electrodynamics with a Single Quantum Dot Coupled to a Photonic Molecule  

E-Print Network [OSTI]

We demonstrate the effects of cavity quantum electrodynamics for a quantum dot coupled to a photonic molecule, consisting of a pair of coupled photonic crystal cavities. We show anti-crossing between the quantum dot and the two super-modes of the photonic molecule, signifying achievement of the strong coupling regime. From the anti-crossing data, we estimate the contributions of both mode-coupling and intrinsic detuning to the total detuning between the super-modes. Finally, we also show signatures of off-resonant cavity-cavity interaction in the photonic molecule.

Arka Majumdar; Armand Rundquist; Michal Bajcsy; Jelena Vu?kovi?

2012-01-30T23:59:59.000Z

353

Transition Plan | Department of Energy  

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

and training needs for system operation and maintenance, planning for data migration, etc Transition Plan More Documents & Publications System Design Feasibility Study Report...

354

X-ray luminescence of CdTe quantum dots in LaF{sub 3}:Ce/CdTe nanocomposites  

SciTech Connect (OSTI)

CdTe quantum dots have intense photoluminescence but exhibit almost no x-ray luminescence. However, intense x-ray luminescence from CdTe quantum dots is observed in LaF{sub 3}:Ce/CdTe nanocomposites. This enhancement in the x-ray luminescence of CdTe quantum dots is attributed to the energy transfer from LaF{sub 3}:Ce to CdTe quantum dots in the nanocomposites. The combination of LaF{sub 3}:Ce nanoparticles and CdTe quantum dots makes LaF{sub 3}:Ce/CdTe nanocomposites promising scintillators for radiation detection.

Hossu, Marius; Liu Zhongxin; Yao Mingzhen; Ma Lun; Chen Wei

2012-01-02T23:59:59.000Z

355

Photoluminescence from In0.5Ga0.5As/GaP quantum dots coupled to photonic crystal cavities  

E-Print Network [OSTI]

We demonstrate room temperature visible wavelength photoluminescence from In0.5Ga0.5As quantum dots embedded in a GaP membrane. Time-resolved above band photoluminescence measurements of quantum dot emission show a biexpontential decay with lifetimes of ~200 ps. We fabricate photonic crystal cavities which provide enhanced outcoupling of quantum dot emission, allowing the observation of narrow lines indicative of single quantum dot emission. This materials system is compatible with monolithic integration on Si, and is promising for high efficiency detection of single quantum dot emission as well as optoelectronic devices emitting at visible wavelengths.

Kelley Rivoire; Sonia Buckley; Yuncheng Song; Minjoo Larry Lee; Jelena Vuckovic

2012-01-05T23:59:59.000Z

356

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results  

SciTech Connect (OSTI)

This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.

Chandler, K.; Eudy, L.

2008-10-01T23:59:59.000Z

357

Cryogenic spectroscopy of ultra-low density colloidal lead chalcogenide quantum dots on chip-scale optical cavities towards single quantum dot near-infrared cavity QED  

E-Print Network [OSTI]

We present evidence of cavity quantum electrodynamics from a sparse density of strongly quantum-confined Pb-chalcogenide nanocrystals (between 1 and 10) approaching single-dot levels on moderately high-Q mesoscopic silicon optical cavities. Operating at important near-infrared (1500-nm) wavelengths, large enhancements are observed from devices and strong modifications of the QD emission are achieved. Saturation spectroscopy of coupled QDs is observed at 77K, highlighting the modified nanocrystal dynamics for quantum information processing.

Ranojoy Bose; Jie Gao; James F. McMillan; Alex D. Williams; Chee Wei Wong

2008-12-01T23:59:59.000Z

358

Section 9: Laminar flows and transition 1 Section 9: Laminar flows and transition  

E-Print Network [OSTI]

:20 ­ 16:40: Andreas Nold, Martin Oberlack (TU Darmstadt): Connecting the dots: Symme- try Analysis bubble bursting Abstract 17:40 ­ 18:00: Mario Aigner, Stefan Braun (TU Wien): Cauchy Problems

Kohlenbach, Ulrich

359

gray-98.pdf  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched5 Industrial Carbon Capture andDeepwaterfors | National91 A

360

Managing Transition Cows Amanda Pellegrin  

E-Print Network [OSTI]

Managing Transition Cows Amanda Pellegrin Animal Nutrition winter 20009 Tisch, David. Animal Feeds://www.uky.edu/Ag/ Animal Sciences/dairy/ extension/nut00046.pdf. Works Cited Managng Transition Priod in Dairy Cattle Pasture management Pastures and hays comprised of leg- umes and legume-grass mixtures are good sources

Selmic, Sandra

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Intermediate-band solar cells based on quantum dot supracrystals Q. Shao and A. A. Balandina  

E-Print Network [OSTI]

parameter in the photovoltaic PV solar cell technology. It is defined as = FFVocJsc Pin , 1 where FFIntermediate-band solar cells based on quantum dot supracrystals Q. Shao and A. A. Balandina Nano to implement the intermediate-band solar cell with the efficiency exceeding the Shockley-Queisser limit

362

Depleted-heterojunction colloidal quantum dot photovoltaics employing low-cost electrical contacts  

E-Print Network [OSTI]

Department of Materials Science and Engineering, 184 College Street, Toronto, Ontario M5S 3E4, Canada 3 of depleted-heterojunction colloidal quantum dot solar cells, we describe herein a strategy that replaces. © 2010 American Institute of Physics. doi:10.1063/1.3463037 Solar energy harvesting requires

363

Electrical and Thermal Conductivity of Ge/Si Quantum Dot Superlattices  

E-Print Network [OSTI]

. Good carrier mobility and electric con- ductivity are important for thermoelectric materials where-Riverside, Riverside, California 92521, USA Recently proposed thermoelectric applications of quantum dot superlattices made of different material systems depend crucially on the values of the electrical and thermal

364

Theoretical performance of solar cell based on mini-bands quantum dots  

SciTech Connect (OSTI)

The tremendous amount of research in solar energy is directed toward intermediate band solar cell for its advantages compared with the conventional solar cell. The latter has lower efficiency because the photons have lower energy than the bandgap energy and cannot excite mobile carriers from the valence band to the conduction band. On the other hand, if mini intermediate band is introduced between the valence and conduction bands, then the smaller energy photons can be used to promote charge carriers transfer to the conduction band and thereby the total current increases while maintaining a large open circuit voltage. In this article, the influence of the new band on the power conversion efficiency for structure of quantum dots intermediate band solar cell is theoretically investigated and studied. The time-independent Schrödinger equation is used to determine the optimum width and location of the intermediate band. Accordingly, achievement of a maximum efficiency by changing the width of quantum dots and barrier distances is studied. Theoretical determination of the power conversion efficiency under the two different ranges of QD width is presented. From the obtained results, the maximum power conversion efficiency is about 70.42%. It is carried out for simple cubic quantum dot crystal under fully concentrated light. It is strongly dependent on the width of quantum dots and barrier distances.

Aly, Abou El-Maaty M., E-mail: drabouelmaaty@hotmail.com, E-mail: ashraf.nasr@gmail.com [Power Electronics and Energy Conversion Department, ERI, NRCB (Egypt); College of Computer, Qassim University, P.O.B. 6688, Buryadah 51453 (Saudi Arabia); Nasr, A., E-mail: drabouelmaaty@hotmail.com, E-mail: ashraf.nasr@gmail.com [Radiation Engineering Department, NCRRT, Atomic Energy Authority (Egypt); College of Computer, Qassim University, P.O.B. 6688, Buryadah 51453 (Saudi Arabia)

2014-03-21T23:59:59.000Z

365

Hierarchically Structured ZnO Nanorods-Nanosheets for Improved Quantum-Dot-Sensitized Solar Cells  

E-Print Network [OSTI]

). This hierarchical structure had two advantages in improving the power conversion efficiency (PCE) of the solar cells. INTRODUCTION The establishment of low-cost and high-performance solar cells for sustainable energy sourcesHierarchically Structured ZnO Nanorods-Nanosheets for Improved Quantum-Dot-Sensitized Solar Cells

Cao, Guozhong

366

Prospective Article Materials processing strategies for colloidal quantum dot solar cells  

E-Print Network [OSTI]

energy sources, particularly with cheap and plentiful natural gas, solar photovoltaic systems must cost of the solar panels themselves. Third-generation photovoltaic systems, including organic, dye-sensitized, and colloidal quantum dot (CQD) solar cells, offer a path to low-weight, low-cost, and prospectively high

367

FEW ELECTRON QUANTUM DOTS IN InAs/InP CORE SHELL NANOWIRES  

E-Print Network [OSTI]

..." Much effort is being directed at harnessing the potential power of quantum com- puting [7]. At the turn electric field (EDSR) is expected to be orders of magnitudes faster. To this effect, InAs nanowires with a thin shell of InP, are explored as a system where a quantum dot can be defined and probed electrically

Nygård, Jesper

368

Effect of the (OH) Surface Capping on ZnO Quantum Dots  

E-Print Network [OSTI]

in air at different temperatures from 150­500 C for 30 min. In comparison, highly purified bulk Zn is related to oxygen deficiency [1]; the other is a much narrower ultraviolet (UV) emission band at around, compared with good quality ZnO single crystals or ZnO powders, the UV bandgap luminescence in quantum dots

Nabben, Reinhard

369

Single hole quantum dot transistors in silicon Effendi Leobandung, Lingjie Guo, and Stephen Y. Choua)  

E-Print Network [OSTI]

of the gate voltage have been observed at temperatures over 81 K and drain biases over 66 mV. The oscillations to the drain. As the gate voltage was scanned, the drain current i.e., the hole current oscil- lated Fig. 3-dot transistors were fabricated in silicon-on-insulator. Strong oscillations in the drain current as a function

370

A Study Of Semiconductor Quantum Dots In The Application To Terahertz Sensors  

E-Print Network [OSTI]

A Study Of Semiconductor Quantum Dots In The Application To Terahertz Sensors Raymond Davis M and referenced as part of background information used in this project. Raymond Davis October 1, 2011 ii #12 sensors. For detection of terahertz radia- tion we probe charge excitations of QDs caused

Sheldon, Nathan D.

371

Wave-Function Mapping of Graphene Quantum Dots with Soft Confinement D. Subramaniam,1  

E-Print Network [OSTI]

Wave-Function Mapping of Graphene Quantum Dots with Soft Confinement D. Subramaniam,1 F. Libisch,2) Using low-temperature scanning tunneling spectroscopy, we map the local density of states of graphene the graphene K point, the electronic properties of the QDs are dominantly graphenelike. Indeed, we compare

Florian, Libisch

372

Eigenvalues imbedded in the band spectrum for the periodic array of quantum dots  

E-Print Network [OSTI]

) Department of Higher Mathematics, Institute of Fine Mechanics and Optics, Sablinskaya 14, St. II. Model We consider an array of quantum dots displaced in the nodes of a plane lattice \\Gamma which is invariant with respect to translations by vectors of a Bravais lattice \\Lambda. We assume that 0 2 \\Gamma

373

Lead-position dependent regular oscillations and random fluctuations of conductance in graphene quantum dots  

E-Print Network [OSTI]

Lead-position dependent regular oscillations and random fluctuations of conductance in graphene.1088/0953-8984/25/8/085502 Lead-position dependent regular oscillations and random fluctuations of conductance in graphene quantum, for graphene quantum dots, the conductance variations with the lead positions. Since for graphene the types

Lai, Ying-Cheng

374

Single pulse ultrafast laser imprinting of axial dot arrays in bulk glasses C. Mauclair,1,  

E-Print Network [OSTI]

Single pulse ultrafast laser imprinting of axial dot arrays in bulk glasses C. Mauclair,1, A sam- ples were irradiated with 160 fs pulses from an 800 nm Ti:Sapphire amplified ultrafast laser.mauclair@univ-st-etienne.fr Compiled December 20, 2010 Ultrafast laser processing of bulk transparent materials can significantly gain

Paris-Sud XI, Université de

375

Infrared and photoluminescence spectroscopy of p-doped self-assembled Ge dots on Si  

E-Print Network [OSTI]

Infrared and photoluminescence spectroscopy of p-doped self-assembled Ge dots on Si L. P Received 14 June 1999; accepted for publication 17 August 1999 We report infrared photocurrent PC-8 Quantum well infrared photodetector QWIP technol- ogy has matured rapidly in the last several years.1

Rokhinson, Leonid

376

Growth of a single freestanding multiwall carbon nanotube on each nanonickel dot  

E-Print Network [OSTI]

that the structures are indeed hollow nanotubes. The diameter and height depend on the nickel dot size and growth time displays FEDs . Attempts to manipulate nano- tubes for these applications have been made by postgrowth deposition CVD on mesopo- rous silica with imbedded iron particles.9 The growth of large arrays of well

Reed, Mark

377

Intersubband absorption in boron-doped multiple Ge quantum dots J. L. Liu,a)  

E-Print Network [OSTI]

Intersubband absorption in boron-doped multiple Ge quantum dots J. L. Liu,a) W. G. Wu, A. Balandin; accepted for publication 3 November 1998 The intersubband absorption in self-assembled boron-doped multiple and undoped Si barriers. The infrared absorption as a function of wavelength is measured by Fourier transform

378

Tuning the optical properties of dilute nitride site controlled quantum dots  

SciTech Connect (OSTI)

We show that deterministic control of the properties of pyramidal site-controlled quantum dots (QD) could be achieved by exposing the QD layer to nitrogen precursor unsymmetrical dimethylhydrazine (UDMHy). The properties that could be tuned include an expected emission reduction in dilute nitride materials, excitonic pattern (biexciton binding energy) and improved carrier confinement potential symmetry (reduced fine-structure splitting)

Juska, G.; Dimastrodonato, V.; Mereni, L. O.; Gocalinska, A.; Pelucchi, E. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

2013-12-04T23:59:59.000Z

379

Fine Structure of Highly Charged Excitons in Semiconductor Quantum Dots B. Urbaszek,1  

E-Print Network [OSTI]

quantum dots (QDs) are artificial atoms whose properties can be individually measured in their solid, the degeneracy of the excitonic ground state is lifted by the electron-hole (EH) exchange interaction, resultingV, they can be much larger in semiconductor nanocrystals [3] or polymers [4]. In all these systems

Ludwig-Maximilians-Universität, München

380

Photovoltaic nanopillar radial junction diode architecture enhanced by integrating semiconductor quantum dot nanocrystals as light harvesters  

E-Print Network [OSTI]

Photovoltaic nanopillar radial junction diode architecture enhanced by integrating semiconductor hybridized, radial p-n junction based, nanopillar solar cells with photovoltaic performance enhanced. By furnishing Si based nanopillar photovoltaic diodes with CdSe quantum dots, we experimentally showed up

Demir, Hilmi Volkan

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Cu2ZnSnS4 nanocrystals and graphene quantum dots for photovoltaics Xukai Xinab  

E-Print Network [OSTI]

Cu2ZnSnS4 nanocrystals and graphene quantum dots for photovoltaics Jun Wang,a Xukai Xinab advances in the synthesis and utilization of CZTS nanocrystals and colloidal GQDs for photovoltaics emerged to achieve low cost, high perfor- mance photovoltaics, including organic solar cells,2­6 dye

Lin, Zhiqun

382

Study of the self-organization processes in lead sulfide quantum dots  

SciTech Connect (OSTI)

A procedure is described for the synthesis of nanoparticles based on lead chalcogenides. The procedure combines the synthesis of colloidal quantum dots (QDs) in aqueous solutions with simultaneous organization of the QDs into ordered arrays. The processes of the self-organization of QDs are analyzed at the nano- and microscopic levels by the photoluminescence method, atomic-force microscopy, and optical microscopy.

Tarasov, S. A., E-mail: SATarasov@mail.ru; Aleksandrova, O. A.; Maksimov, A. I.; Maraeva, E. V.; Matyushkin, L. B.; Men’kovich, E. A.; Moshnikov, V. A. [St. Petersburg Electrotechnical University LETI (Russian Federation); Musikhin, S. F. [St. Petersburg State Polytechnic University (Russian Federation)

2014-12-15T23:59:59.000Z

383

Coupling an electron spin in a semiconductor quantum dot to an optical nano-cavity  

E-Print Network [OSTI]

We propose a scheme to efficiently couple a single quantum dot electron spin to an optical nano-cavity, which enables us to simultaneously benefit from a cavity as an efficient photonic interface, as well as to perform high fidelity (nearly 100%) spin initialization and manipulation achievable in bulk semiconductors. Moreover, the presence of the cavity speeds up the spin initialization process beyond GHz.

Arka Majumdar; Per Kaer; Michal Bajcsy; Erik D. Kim; Konstantinos G. Lagoudakis; Armand Rundquist; Jelena Vuckovic

2013-04-07T23:59:59.000Z

384

Synthesis and optical properties of cadmium selenide quantum dots for white light-emitting diode application  

SciTech Connect (OSTI)

Highlights: ? Stable CdSe QDs were synthesized by the one-step and two-level process respectively. ? The fabricated white LEDs show good white balance. ? CdSe QDs present well green to yellow band luminescence. ? CdSe QDs displayed a broad excitation band. - Abstract: Yellow light-emitting cadmium selenide quantum dots were synthesized using one-step and two-step methods in an aqueous medium. The structural luminescent properties of these quantum dots were investigated. The obtained cadmium selenide quantum dots displayed a broad excitation band suitable for blue or near-ultraviolet light-emitting diode applications. White light-emitting diodes were fabricated by coating the cadmium selenide samples onto a 460 nm-emitting indium gallium nitrite chip. Both samples exhibited good white balance. Under a 20 mA working current, the white light-emitting diode fabricated via the one-step and two-step methods showed Commission Internationale de l’Éclairage coordinates at (0.27, 0.23) and (0.27, 0.33), respectively, and a color rendering index equal to 41 and 37, respectively. The one-step approach was simpler, greener, and more effective than the two-step approach. The one-step approach can be enhanced by combining cadmium selenide quantum dots with proper phosphors.

Xu, Xianmei; Wang, Yilin; Gule, Teri; Luo, Qiang [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Zhou, Liya, E-mail: zhouliyatf@163.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Gong, Fuzhong [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China)

2013-03-15T23:59:59.000Z

385

PHYSICAL REVIEW B 85, 085117 (2012) Spin thermopower in interacting quantum dots  

E-Print Network [OSTI]

current without accompanying charge current. For temperatures and fields at or above the Kondo temperature, we relate the spin-Seebeck coefficient to the charge-Seebeck coefficient of a negative-U quantum dot applications, including power generation, refrigeration, and temperature measurement.1 Thermoelectric phenomena

Ramsak, Anton

386

Fuel Cell Transit Bus Coordination and Evaluation Plan California...  

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

Transit Bus Coordination and Evaluation Plan California Fuel Cell Transit Evaluation Team Fuel Cell Transit Bus Coordination and Evaluation Plan California Fuel Cell Transit...

387

Auger recombination and intraband absorption of two-photon-excited carriers in colloidal CdSe quantum dots  

E-Print Network [OSTI]

Se quantum dots Yingli Qu and Wei Jia Department of Physics, National University of Singapore, Singapore 117542, Republic of Singapore Yuangang Zheng and Jackie Y. Ying Institute of Bioengineering

Wei, Ji

388

Development of a Bioorthogonal and Highly Efficient Conjugation Method for Quantum Dots using Tetrazine-Norbornene Cycloaddition  

E-Print Network [OSTI]

We present a bioorthogonal and modular conjugation method for efficient coupling of organic dyes and biomolecules to quantum dots (QDs) using a norbornene?tetrazine cycloaddition. The use of noncoordinating functional ...

Han, Hee-Sun

389

Physica E 34 (2006) 15 Single-shot readout of electron spins in a semiconductor quantum dot  

E-Print Network [OSTI]

states in a semiconductor quantum dot that is robust against charge noise and can be used even when readout (E-RO), the spin levels are positioned around the electrochemical potential of the reservoir mres

390

Role of surface states and defects in the ultrafast nonlinear optical properties of CuS quantum dots  

SciTech Connect (OSTI)

We report facile preparation of water dispersible CuS quantum dots (2–4 nm) and nanoparticles (5–11 nm) through a nontoxic, green, one-pot synthesis method. Optical and microstructural studies indicate the presence of surface states and defects (dislocations, stacking faults, and twins) in the quantum dots. The smaller crystallite size and quantum dot formation have significant effects on the high energy excitonic and low energy plasmonic absorption bands. Effective two-photon absorption coefficients measured using 100 fs laser pulses employing open-aperture Z-scan in the plasmonic region of 800 nm reveal that CuS quantum dots are better ultrafast optical limiters compared to CuS nanoparticles.

Mary, K. A. Ann; Unnikrishnan, N. V., E-mail: nvu100@yahoo.com [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)

2014-07-01T23:59:59.000Z

391

Spin and Conductance-Peak-Spacing Distributions in Large Quantum Dots: A Density-Functional Theory Study  

E-Print Network [OSTI]

of solid-state physics. A semiconductor quantum dot (QD) [1,2]--a nanodevice in which electron motion was regu- lar in shape [24]. Our aim here is to bridge the gap between the two theoretical approaches

Baranger, Harold U.

392

High Throughput Synthesis of Uniform Biocompatible Polymer Beads with High Quantum Dot Loading Using Microfluidic Jet-Mode Breakup  

E-Print Network [OSTI]

Uniform polymer microbeads with highly loaded quantum dots (QDs) are produced using high-throughput coherent jet breakup of a biocompatible poly(ethylene glycol) diacrylate (PEGDA) prepolymer resin, followed by in-line ...

Lee, Seung-Kon

393

Nanoscale optical positioning of single quantum dots for bright, pure, and on-demand single-photon emission  

E-Print Network [OSTI]

Self-assembled, epitaxially-grown InAs/GaAs quantum dots are promising semiconductor quantum emitters that can be integrated on a chip for a variety of photonic quantum information science applications. However, self-assembled growth results in an essentially random in-plane spatial distribution of quantum dots, presenting a challenge in creating devices that exploit the strong interaction of single quantum dots with highly confined optical modes. Here, we present a photoluminescence imaging approach for locating single quantum dots with respect to alignment features with an average (minimum) position uncertainty efficiency (48 % +/- 5 % into a 0.4 numerical aperture lens, close to the theoretically predicted value of 50 %), low multiphoton prob...

Sapienza, Luca; Badolato, Antonio; Srinivasan, Kartik

2015-01-01T23:59:59.000Z

394

Vehicle Technologies Office: Transitioning the Transportation...  

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

Office: Transitioning the Transportation Sector - Exploring the Intersection of H2 Fuel Cell and Natural Gas Vehicles Vehicle Technologies Office: Transitioning the Transportation...

395

Building America Expert Meeting Report: Transitioning Traditional...  

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

Transitioning Traditional HVAC Contractors to Whole House Performance Contractors Building America Expert Meeting Report: Transitioning Traditional HVAC Contractors to Whole House...

396

Records and Information Management Transition Guidance (November...  

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

Records and Information Management Transition Guidance (November 2013) Records and Information Management Transition Guidance (November 2013) This guidance document establishes a...

397

Hole Spin Pumping and Re-pumping in a p-type ?-doped InAs Quantum Dot  

E-Print Network [OSTI]

We have grown high quality p-type {\\delta}-doped InAs quantum dots and have demonstrated coherent spin pumping and repumping of a hole spin in a positively charged quantum dot by means of a single-laser driving scheme under a high magnetic field in the Voigt configuration. Modeling of our system shows excellent qualitative agreement with the experimental findings and further explores the performance of the single-laser scheme for spin pumping and re-pumping.

Konstantinos G. Lagoudakis; Kevin A. Fischer; Tomas Sarmiento; Kai Mueller; Jelena Vu?kovi?

2014-08-29T23:59:59.000Z

398

Determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer quantum dots via spectral analysis of optical signature of the Aharanov-Bohm excitons  

SciTech Connect (OSTI)

For submonolayer quantum dot (QD) based photonic devices, size and density of QDs are critical parameters, the probing of which requires indirect methods. We report the determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer QDs, based on spectral analysis of the optical signature of Aharanov-Bohm (AB) excitons, complemented by photoluminescence studies, secondary-ion mass spectroscopy, and numerical calculations. Numerical calculations are employed to determine the AB transition magnetic field as a function of the type-II QD radius. The study of four samples grown with different tellurium fluxes shows that the lateral size of QDs increases by just 50%, even though tellurium concentration increases 25-fold. Detailed spectral analysis of the emission of the AB exciton shows that the QD radii take on only certain values due to vertical correlation and the stacked nature of the QDs.

Ji, Haojie; Dhomkar, Siddharth; Roy, Bidisha; Kuskovsky, Igor L. [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); The Graduate Center of CUNY, New York, New York 10016 (United States); Shuvayev, Vladimir [Department of Physics, Queens College of CUNY, Queens, New York 11367 (United States); Deligiannakis, Vasilios; Tamargo, Maria C. [The Graduate Center of CUNY, New York, New York 10016 (United States); Department of Chemistry, City College of CUNY, New York, New York 10031 (United States); Ludwig, Jonathan [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States); Smirnov, Dmitry [National High Magnetic Field Laboratory, Tallahassee, Florida 32310 (United States); Wang, Alice [Evans Analytical Group, Sunnyvale, California 94086 (United States)

2014-10-28T23:59:59.000Z

399

Strongly confining bare core CdTe quantum dots in polymeric microdisk resonators  

SciTech Connect (OSTI)

We report on a simple route to the efficient coupling of optical emission from strongly confining bare core CdTe quantum dots (QDs) to the eigenmodes of a micro-resonator. The quantum emitters are embedded into QD/polymer sandwich microdisk cavities. This prevents photo-oxidation and yields the high dot concentration necessary to overcome Auger enhanced surface trapping of carriers. In combination with the very high cavity Q-factors, interaction of the QDs with the cavity modes in the weak coupling regime is readily observed. Under nanosecond pulsed excitation the CdTe QDs in the microdisks show lasing with a threshold energy as low as 0.33 ?J.

Flatae, Assegid, E-mail: assegid.flatae@kit.edu; Grossmann, Tobias; Beck, Torsten; Wiegele, Sarah; Kalt, Heinz [Institute of Applied Physics and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Str.1, 76131 Karlsruhe (Germany)

2014-01-01T23:59:59.000Z

400

Phonon-assisted robust and deterministic two-photon biexciton preparation in a quantum dot  

E-Print Network [OSTI]

We investigate both experimentally and theoretically a simple yet more robust and flexible alternative to Rabi oscillation-type biexciton preparation protocols traditionally used for semiconductor quantum dots. The quantum dot is excited by a strong laser pulse positively detuned from the two-photon resonance yielding an on demand initialization of the biexciton state by making use of the phonon-induced thermalization of the photon dressed states. It is shown that for excitation pulses in the picosecond range, a stable and high fidelity of up to $f_{XX}=0.98\\pm 0.01$ is reached. Notably, the generated photons show similar coherence properties as measured in the resonant two-photon scheme. This protocol is a powerful tool for the control of complex solid state systems combining radiative cascades, entanglement and resonant cavity modes.

S. Bounouar; M. Müller; A. M. Barth; M. Glässl; V. M. Axt; P. Michler

2014-08-29T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

High open circuit voltages of solar cells based on quantum dot and dye hybrid-sensitization  

SciTech Connect (OSTI)

A type of solar cell based on quantum dot (QD) and dye hybrid-sensitized mesoporous TiO{sub 2} film electrode was designed and reported. The electrode was consisted of a TiO{sub 2} nanoparticle (NP) thin film layer sensitized with CdS quantum dot (QD) and an amorphous TiO{sub 2} coated TiO{sub 2} NP thin film layer that sensitized with C106 dye. The amorphous TiO{sub 2} layer was obtained by TiCl{sub 4} post-treatment to improve the properties of solar cells. Research showed that the solar cells fabricated with as-prepared hybrid-sensitized electrode exhibited excellent photovoltaic performances and a fairly high open circuit voltage of 796?mV was achieved.

Zhao, Yujie; Zhao, Wanyu; Chen, Jingkuo; Li, Huayang; Fu, Wuyou, E-mail: hari@hpu.edu.cn, E-mail: fuwy56@163.com; Sun, Guang; Cao, Jianliang; Zhang, Zhanying [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China)] [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China); Bala, Hari, E-mail: hari@hpu.edu.cn, E-mail: fuwy56@163.com [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China) [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China); College of Chemistry and Chemical Engineering, Inner Mongolia University for the Nationalities, Tongliao 028043 (China)

2014-01-06T23:59:59.000Z

402

Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared  

SciTech Connect (OSTI)

Our previous work demonstrates that Quasi-Type II CdSe/CdS core-shell quantum dots with thick shells (3-5 nm) exhibit unique photophysical characteristics, including improved chemical robustness over typical thin-shelled core/shell systems and the elimination of blinking through suppression of nonradiative Auger recombination. Here we describe a new thick-shelled heterostructure, InP/CdS, which exhibits a Type II bandgap alignment producing near-infrared (NIR) emission. Samples with a range of shell thicknesses were synthesized, enabling shell-thickness-dependent study of the absorbance and emission spectra, fluorescence lifetimes, and quantum yields. InP/CdS/ZnS core/shell/shell structures were also synthesized to reduce cadmium exposure for applications in the biological environment. Single particle spectroscopy indicates reduced blinking and improved photostability with increasing shell thickness, resulting in thick-shelled dots that are appropriate for single-particle tracking measurements with NIR emission.

Dennis, Allison M. [Los Alamos National Laboratory; Mangum, Benjamin D. [Los Alamos National Laboratory; Piryatinski, Andrei [Los Alamos National Laboratory; Park, Young-Shin [Los Alamos National Laboratory; Htoon, Han [Los Alamos National Laboratory; Hollingsworth, Jennifer A. [Los Alamos National Laboratory

2012-06-21T23:59:59.000Z

403

Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance  

SciTech Connect (OSTI)

In this work, we demonstrate (1) a facile method to prepare Mn doped CdSe quantum dots (QDs) on Zn{sub 2}SnO{sub 4} photoanodes by pulsed laser deposition and (2) improved device performance of quantum dot sensitized solar cells of the Mn doped QDs (CdSe:Mn) compared to the undoped QDs (CdSe). The band diagram of photoanode Zn{sub 2}SnO{sub 4} and sensitizer CdSe:Mn QD is proposed based on the incident-photon-to-electron conversion efficiency (IPCE) data. Mn-modified band structure leads to absorption at longer wavelengths than the undoped CdSe QDs, which is due to the exchange splitting of the CdSe:Mn conduction band by the Mn dopant. Three-fold increase in the IPCE efficiency has also been observed for the Mn doped samples.

Dai, Qilin; Wang, Wenyong, E-mail: wwang5@uwyo.edu, E-mail: jtang2@uwyo.edu; Tang, Jinke, E-mail: wwang5@uwyo.edu, E-mail: jtang2@uwyo.edu [Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071 (United States); Sabio, Erwin M. [Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071 (United States)

2014-05-05T23:59:59.000Z

404

Height stabilization of GaSb/GaAs quantum dots by Al-rich capping  

SciTech Connect (OSTI)

GaSb quantum dots (QDs) in a GaAs matrix are investigated with cross-sectional scanning tunneling microscopy (X-STM) and photoluminescence (PL). We observe that Al-rich capping materials prevent destabilization of the nanostructures during the capping stage of the molecular beam epitaxy (MBE) growth process and thus preserves the QD height. However, the strain induced by the absence of destabilization causes many structural defects to appear around the preserved QDs. These defects originate from misfit dislocations near the GaSb/GaAs interface and extend into the capping layer as stacking faults. The lack of a red shift in the QD PL suggests that the preserved dots do not contribute to the emission spectra. We suggest that a better control over the emission wavelength and an increase of the PL intensity is attainable by growing smaller QDs with an Al-rich overgrowth.

Smakman, E. P., E-mail: e.p.smakman@tue.nl; Koenraad, P. M. [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); DeJarld, M.; Martin, A. J.; Millunchick, J. [Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Luengo-Kovac, M.; Sih, V. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-09-01T23:59:59.000Z

405

Carrier transfer from InAs quantum dots to ErAs metal nanoparticles  

SciTech Connect (OSTI)

Erbium arsenide (ErAs) is a semi-metallic material that self-assembles into nanoparticles when grown in GaAs via molecular beam epitaxy. We use steady-state and time-resolved photoluminescence to examine the mechanism of carrier transfer between indium arsenide (InAs) quantum dots and ErAs nanoparticles in a GaAs host. We probe the electronic structure of the ErAs metal nanoparticles (MNPs) and the optoelectronic properties of the nanocomposite and show that the carrier transfer rates are independent of pump intensity. This result suggests that the ErAs MNPs have a continuous density of states and effectively act as traps. The absence of a temperature dependence tells us that carrier transfer from the InAs quantum dots to ErAs MNPs is not phonon assisted. We show that the measured photoluminescence decay rates are consistent with a carrier tunneling model.

Haughn, C. R.; Chen, E. Y.; Zide, J. M. O.; Doty, M. F., E-mail: doty@udel.edu [Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); Steenbergen, E. H.; Bissell, L. J.; Eyink, K. G. [AFRL/RXAN, Wright Patterson AFB, Ohio 45433 (United States)

2014-09-08T23:59:59.000Z

406

Note: Near infrared spectral and transient measurements of PbS quantum dots luminescence  

SciTech Connect (OSTI)

We describe an experimental setup for the characterization of luminescence from nanostructures. The setup is intended for steady-state and time-resolved luminescence measurements in the near-infrared region. The setup allows us to study spectral luminescence properties in the spectral range of 0.8–2.0 ?m with high spectral resolution and kinetic luminescence properties between 0.8 and 1.7 ?m with a time resolution of 3 ns. The capabilities of the system are illustrated by taking luminescence measurements from PbS quantum dots. We established the size dependencies of the optical properties of the PbS quantum dots over a wide spectral range. Finally, the energy transfer process was studied with a high temporal and spectral resolution.

Parfenov, P. S., E-mail: qrspeter@pochta.ru; Litvin, A. P., E-mail: litvin88@gmail.com; Ushakova, E. V.; Fedorov, A. V.; Baranov, A. V. [National Research University of Informational Technologies, Mechanics and Optics, 197101 49, Kronverkskiy pr., Saint Petersburg (Russian Federation)] [National Research University of Informational Technologies, Mechanics and Optics, 197101 49, Kronverkskiy pr., Saint Petersburg (Russian Federation); Berwick, K. [School of Electronic and Communications Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 (Ireland)] [School of Electronic and Communications Engineering, Dublin Institute of Technology, Kevin Street, Dublin 8 (Ireland)

2013-11-15T23:59:59.000Z

407

Decision making based on optical excitation transfer via near-field interactions between quantum dots  

SciTech Connect (OSTI)

Optical near-field interactions between nanostructured matters, such as quantum dots, result in unidirectional optical excitation transfer when energy dissipation is induced. This results in versatile spatiotemporal dynamics of the optical excitation, which can be controlled by engineering the dissipation processes and exploited to realize intelligent capabilities such as solution searching and decision making. Here, we experimentally demonstrate the ability to solve a decision making problem on the basis of optical excitation transfer via near-field interactions by using colloidal quantum dots of different sizes, formed on a geometry-controlled substrate. We characterize the energy transfer behavior due to multiple control light patterns and experimentally demonstrate the ability to solve the multi-armed bandit problem. Our work makes a decisive step towards the practical design of nanophotonic systems capable of efficient decision making, one of the most important intellectual attributes of the human brain.

Naruse, Makoto, E-mail: naruse@nict.go.jp [Photonic Network Research Institute, National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795 (Japan); Nomura, Wataru; Ohtsu, Motoichi [Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656 (Japan); Aono, Masashi [Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguru-ku, Tokyo 152-8550 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi-shi, Saitama 332-0012 (Japan); Sonnefraud, Yannick; Drezet, Aurélien; Huant, Serge [Université Grenoble Alpes, Inst. NEEL, F-38000 Grenoble (France); CNRS, Inst. NEEL, F-38042 Grenoble (France); Kim, Song-Ju [WPI Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2014-10-21T23:59:59.000Z

408

Enhanced single-photon emission from a quantum dot in a micropost microcavity  

E-Print Network [OSTI]

We demonstrate a single-photon source based on a quantum dot in a micropost microcavity that exhibits a large Purcell factor together with a small multi-photon probability. For a quantum dot on resonance with the cavity, the spontaneous emission rate is increased by a factor of five, while the probability to emit two or more photons in the same pulse is reduced to 2% compared to a Poisson-distributed source of the same intensity. In addition to the small multi-photon probability, such a strong Purcell effect is important in a single-photon source for improving the photon outcoupling efficiency and the single-photon generation rate, and for bringing the emitted photon pulses closer to the Fourier transform limit.

Jelena Vuckovic; David Fattal; Charles Santori; Glenn Solomon; Yoshihisa Yamamoto

2003-07-03T23:59:59.000Z

409

Zajac, R.N. 1999. Understanding the seafloor landscape in relation to assessing and managing impacts on coastal environments. Pp 211-227 in: J.S. Gray, W. Ambrose Jr., A. Szaniawska (eds) Biogeochemical Cycling and Sediment  

E-Print Network [OSTI]

of organisms, and have borne much of man's long history of development and associated environmental impacts IN RELATION TO IMPACT ASSESSMENT AND ENVIRONMENTAL MANAGEMENT IN COASTAL MARINE SEDIMENTS ROMAN N. ZAJAC impacts on coastal environments. Pp 211-227 in: J.S. Gray, W. Ambrose Jr., A. Szaniawska (eds

Zajac, Roman N.

410

Local droplet etching – Nanoholes, quantum dots, and air-gap heterostructures  

SciTech Connect (OSTI)

Local droplet etching (LDE) allows the self-organized generation of nanoholes in semiconductor surfaces and is fully compatible with molecular beam epitaxy (MBE). The influence of the process parameters as well as of droplet and substrate materials on the LDE nanohole morphology is discussed. Furthermore, recent applications of LDE, the fabrication of quantum dots by hole filling and the creation of air-gap heterostructures are addressed.

Heyn, Ch.; Sonnenberg, D.; Graf, A.; Kerbst, J.; Stemmann, A.; Hansen, W. [Institute of Applied Physics, University of Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany)

2014-05-15T23:59:59.000Z

411

Observations of Rabi oscillations in a non-polar InGaN quantum dot  

SciTech Connect (OSTI)

Experimental observation of Rabi rotations between an exciton excited state and the crystal ground state in a single non-polar InGaN quantum dot is presented. The exciton excited state energy is determined by photoluminescence excitation spectroscopy using two-photon excitation from a pulsed laser. The population of the exciton excited state is seen to undergo power dependent damped Rabi oscillations.

Reid, Benjamin P. L., E-mail: benjamin.reid@physics.ox.ac.uk; Chan, Christopher C. S.; Taylor, Robert A. [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Kocher, Claudius [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Konstanz University, Konstanz (Germany); Zhu, Tongtong; Oehler, Fabrice; Emery, Robert; Oliver, Rachel A. [Department of Materials Science and Metallurgy, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2014-06-30T23:59:59.000Z

412

Tuning photoluminescence of reduced graphene oxide quantum dots from blue to purple  

SciTech Connect (OSTI)

Reduced graphene oxide quantum dots (rGOQDs) were synthesized by annealing GOQDs in H{sub 2} atmosphere. The photoluminescence (PL) properties of GOQDs and the rGOQDs samples were investigated. The results showed that compared to GOQDs, a blue to purple tunable PL of rGOQDs can be obtained by regulating the annealing temperature. The increase fraction of the newly formed isolated sp{sup 2} clusters may be responsible for the observed tunable PL.

Liu, Fuchi [Physics Department and Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); College of Physics and Technology, Guangxi Normal University, Guilin 541004 (China); Tang, Tao; Feng, Qian; Li, Ming; Liu, Yuan; Tang, Nujiang, E-mail: tangnujiang@nju.edu.cn; Zhong, Wei; Du, Youwei [Physics Department and Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China)

2014-04-28T23:59:59.000Z

413

Probing the ladder of dressed states and nonclassical light generation in quantum dot-cavity QED  

E-Print Network [OSTI]

We investigate the photon induced tunneling phenomena in a photonic crystal cavity containing a strongly coupled quantum dot and describe how this tunneling can be used to generate photon states consisting mainly of a particular Fock state. Additionally, we study experimentally the photon-induced tunneling as a function of excitation laser power and frequency and show the signature of second rung of the Jaynes-Cummings Hamiltonian in the observed photon-statistics.

Arka Majumdar; Michal Bajcsy; Jelena Vuckovic

2011-10-21T23:59:59.000Z

414

Second harmonic generation from direct band gap quantum dots pumped by femtosecond laser pulses  

SciTech Connect (OSTI)

We report on nonlinear optical experiments performed on Cu{sub 2}S quantum dots (QDs) pumped by femtosecond laser pulses. We conduct a theoretical simulation and experiments to determine their second harmonic generation characteristics. Furthermore, we demonstrate that the QDs have a second harmonic generation conversion efficiency of up to 76%. Our studies suggest that these Cu{sub 2}S QDs can be used for solar cells, bioimaging, biosensing, and electric detection.

Liu, Liwei, E-mail: liulw@cust.edu.cn; Wang, Yue; Hu, Siyi; Ren, Yu; Huang, Chen [School of Science, Changchun University of Science and Technology, Changchun, Jilin 130022, People's Republic of China and International Joint Research Center for Nanophotonics and Biophotonics, Changchun University of Science and Technology, Changchun, Jilin 130022 (China)

2014-02-21T23:59:59.000Z

415

Regional Transit System: Return on Investment Assessment  

E-Print Network [OSTI]

Regional Transit System: Return on Investment Assessment May 2014 #12;1 Today's agenda Itasca transit options Enables strategic, efficient investment in long-term infrastructure, e.g., energy grid are seeking cities with good transit Transit can be a cost-efficient way to add capacity in corridors

Minnesota, University of

416

Formal Transition in Agent Organizations Eric Matson  

E-Print Network [OSTI]

, the company's management must understand the methodology and process of transition, or more generally termedFormal Transition in Agent Organizations Eric Matson Department of Computer Science and Engineering define organization transition. Specifically, we describe a formal process of organi- zation transition

Deloach, Scott A.

417

Quantum dot based memory devices: Current status and future prospect by simulation perspective  

SciTech Connect (OSTI)

We discuss the simulation of floating gate MOSFET memory performance consists of Si/Ge/Si quantum dots for electronics storage nodes with higk-? material as the tunnel oxide. Heterostructure quantum dot was proposed to maintain the good memory performance without losing the long retention characteristic. As the results, retention time could be increase significantly without deteriorating the writing/erasing speed. By selected the dot size of 9–15nm and the tunnel oxide thickness of 2nm, the retention characteristic can reach up to 10{sup 9}s while the writing and erasing time at the order of 10{sup ?6}s. By replace the SiO{sub 2} tunnel oxide with high-? material such as HfO{sub 2}, ZrO{sub 2}, and Y{sub 2}O{sub 3} the leakage current due to the shrinkage of tunnel oxide thickness can be suppressed by the factor of 10 for the EOT lower than ?1nm. Moreover, the charge-trapping that generated by the defect at Si substrate and higk-? material interface are fully considered. We found that, the charge-trapping affects the retention time and memory operation performance. By increasing the charge-trapping depth and width, the memory operation time decrease significantly while the retention characteristic slightly improved.

Darma, Y., E-mail: yudi@fi.itb.ac.id; Rusydi, A., E-mail: yudi@fi.itb.ac.id [Department of Physics, Institut Teknologi Bandung, Ganesa 10 Bandung 40132, Indonesia and NUSNNI-NanoCore, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 and Singapore Synchrotron Light Source, National U (Singapore)

2014-02-24T23:59:59.000Z

418

Evaluating charge noise acting on semiconductor quantum dots in the circuit quantum electrodynamics architecture  

SciTech Connect (OSTI)

We evaluate the charge noise acting on a GaAs/GaAlAs based semiconductor double quantum dot dipole-coupled to the voltage oscillations of a superconducting transmission line resonator. The in-phase (I) and the quadrature (Q) components of the microwave tone transmitted through the resonator are sensitive to charging events in the surrounding environment of the double dot with an optimum sensitivity of 8.5×10{sup ?5}?e/?(Hz). A low frequency 1/f type noise spectrum combined with a white noise level of 6.6×10{sup ?6} e{sup 2}/Hz above 1?Hz is extracted, consistent with previous results obtained with quantum point contact charge detectors on similar heterostructures. The slope of the 1/f noise allows to extract a lower bound for the double-dot charge qubit dephasing rate which we compare to the one extracted from a Jaynes-Cummings Hamiltonian approach. The two rates are found to be similar emphasizing that charge noise is the main source of dephasing in our system.

Basset, J.; Stockklauser, A.; Jarausch, D.-D.; Frey, T.; Reichl, C.; Wegscheider, W.; Wallraff, A.; Ensslin, K.; Ihn, T. [Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich (Switzerland)

2014-08-11T23:59:59.000Z

419

Spectral properties of a hybrid-qubit model based on a two-dimensional quantum dot  

E-Print Network [OSTI]

The design and study of hybrid qubits is driven by their ability to get along the best of charge qubits and of spin qubits, {\\em i.e.} the speed of operation of the former and the very slow decoherence rates of the latter ones. There are several proposals to implement hybrid qubits, this works focuses on the spectral properties of an one-electron hybrid qubit. By design, the information would be stored in the electronic spin and the switching between the qubit basis states would be achieved using an external ac electric field. The electron is confined in a two-dimensional quantum dot, whose confining potential is given by a quartic potential, features that are typical of GaAS quantum dots. Besides the confining potential that characterizes the quantum dot there are two static magnetic fields applied to the system, one is a large constant Zeeman field and the other one has a constant gradient. We study the spectral properties of the model Hamiltonian, a Scr\\"odinger-Pauli Hamiltonian with realistic parameters, using the Ritz method. In particular, we look for regions of the parameter space where the lowest eigenenergies and their eigenfunctions allow to define a qubit which is stable under perturbations to the design parameters. We put special attention to the constraints that the design imposes over the magnetic fields, the tuning of the energy gap between the qubit states and the expectation value of the spin operator where the information would be stored.

Alba Y. Ramos; Omar Osenda

2015-03-27T23:59:59.000Z

420

Energy Loss of Neutrinos in 20 M{sub {center_dot}} and 40 M{sub {center_dot}} Massive Stars  

SciTech Connect (OSTI)

The progress from the theoretical and experimental aspects in neutrino physics shines light into neutrino physics as well as in astrophysics. It is known that when neutrinos pass through a medium, the neutrinos interact with electrons before emerging from the stars with an effective potential energy produced due to coherent forward scatterings that occurred in the medium. This potential engenders significant changes in the neutrino masses and their mixing in the medium. Thus electron neutrinos would oscillate into different mass eigenstate and this is dependent on the energy of the neutrinos. Some of the energy will be lost in the coherent scattering with the electrons by the charged current interaction. We have calculated the energy loss of the neutrinos by using a stopping power equation for both rotating and non-rotating 20 M{sub {center_dot}} and 40 M{sub {center_dot}} stars. The total energy loss of neutrinos depends on the electron density in the stars and on the survival probability of the electron neutrino. For high electron density profile and the survival probability, the energy loss will be significant.

Sofiah Ahmad, Nor; Yusof, Norhasliza; Abu Kassim, Hasan [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Photoconductivity of structures based on the SnO{sub 2} porous matrix coupled with core-shell CdSe/CdS quantum dots  

SciTech Connect (OSTI)

Embedding of quantum dots into porous oxide matrixes is a perspective technique for photosensitization of a structure. We show that the sensitization efficiency may be increased by the use of core-shell quantum dots. It is demonstrated that the photoresponse amplitude in a SnO{sub 2} porous matrix with CdSe/CdS quantum dots depends non-monotonously on the number of atomic layers in a shell. The best results are obtained for SnO{sub 2} matrixes coupled with the quantum dots with three atomic layers of a shell. Mechanisms responsible for the structure sensitization are discussed.

Drozdov, K. A.; Kochnev, V. I.; Dobrovolsky, A. A.; Khokhlov, D. R. [Department of Physics, Moscow State University, 119991 Moscow (Russian Federation)] [Department of Physics, Moscow State University, 119991 Moscow (Russian Federation); Popelo, A. V. [Department of Materials Science, Moscow State University, 119991 Moscow (Russian Federation)] [Department of Materials Science, Moscow State University, 119991 Moscow (Russian Federation); Rumyantseva, M. N.; Gaskov, A. M.; Ryabova, L. I. [Department of Chemistry, Moscow State University, 119991 Moscow (Russian Federation)] [Department of Chemistry, Moscow State University, 119991 Moscow (Russian Federation); Vasiliev, R. B. [Department of Materials Science, Moscow State University, 119991 Moscow (Russian Federation) [Department of Materials Science, Moscow State University, 119991 Moscow (Russian Federation); Department of Chemistry, Moscow State University, 119991 Moscow (Russian Federation)

2013-09-23T23:59:59.000Z

422

Measuring Cost Variability in Provision of Transit Service  

E-Print Network [OSTI]

Comprehensive Transit Performance Indicators. UCTC WorkingModal Transit Performance Indicators. Ph.D. dissertation.

Taylor, Brian D.; Garrett, Mark; Iseki, Hiroyuki

2010-01-01T23:59:59.000Z

423

Understanding the electronic structure of CdSe quantum dot-fullerene (C{sub 60}) hybrid nanostructure for photovoltaic applications  

SciTech Connect (OSTI)

By using the density-functional tight binding method, we studied the electronic structure of CdSe quantum dot(QD)-buckminsterfullerene (C{sub 60}) hybrid systems as a function of both the size of the QD and concentration of the fullerene molecule. Our calculation reveals that the lowest unoccupied molecular orbital energy level of the hybrid CdSeQD-C{sub 60} systems lies on the fullerene moiety, whereas the highest occupied molecular orbital (HOMO) energy level lies either on the QD or the fullerene depending on size of the CdSe QD. We explored the possibility of engineering the energy level alignment by varying the size of the CdSe QD. With increase in size of the QD, the HOMO level is shifted upward and crosses the HOMO level of the C{sub 60}-thiol molecule resulting transition from the type-I to type-II band energy alignment. The density of states and charge density plot support these types of band gap engineering of the CdSe-C{sub 60} hybrid systems. This type II band alignment indicates the possibility of application of this nanohybrid for photovoltaic purpose.

Sarkar, Sunandan; Rajbanshi, Biplab; Sarkar, Pranab, E-mail: pranab.sarkar@visva-bharati.ac.in [Department of Chemistry, Visva-Bharati University, Santiniketan 731235 (India)

2014-09-21T23:59:59.000Z

424

Performance-oriented packaging: A guide to identifying and designing. Identifying and designing hazardous materials packaging for compliance with post HM-181 DOT Regulations  

SciTech Connect (OSTI)

With the initial publication of Docket HM-181 (hereafter referred to as HM-181), the U.S. Department of Energy (DOE), Headquarters, Transportation Management Division decided to produce guidance to help the DOE community transition to performance-oriented packagings (POP). As only a few individuals were familiar with the new requirements, elementary guidance was desirable. The decision was to prepare the guidance at a level easily understood by a novice to regulatory requirements. This document identifies design development strategies for use in obtaining performance-oriented packagings that are not readily available commercially. These design development strategies will be part of the methodologies for compliance with post HM-181 U.S. Department of Transportation (DOT) packaging regulations. This information was prepared for use by the DOE and its contractors. The document provides guidance for making decisions associated with designing performance-oriented packaging, and not for identifying specific material or fabrication design details. It does provide some specific design considerations. Having a copy of the regulations handy when reading this document is recommended to permit a fuller understanding of the requirements impacting the design effort. While this document is not written for the packaging specialist, it does contain guidance important to those not familiar with the new POP requirements.

Not Available

1994-08-01T23:59:59.000Z

425

Transition metal sulfide loaded catalyst  

DOE Patents [OSTI]

A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Maroni, Victor A. (Naperville, IL); Iton, Lennox E. (Downers Grove, IL); Pasterczyk, James W. (Westmont, IL); Winterer, Markus (Westmont, IL); Krause, Theodore R. (Lisle, IL)

1994-01-01T23:59:59.000Z

426

Learning Management System Transition Project  

E-Print Network [OSTI]

Learning Management System Transition Project Kickoff Jim Snell Director Instructional Technology Services #12;History · Texas A&M started using the Campus Edition WebCT learning management system (LMS Process March 2012 · Project manager hired March 2012 · ITS project team assigned April 2012 · Contract

427

Transition metal sulfide loaded catalyst  

DOE Patents [OSTI]

A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.

1994-04-26T23:59:59.000Z

428

SunLine Transit Agency, Hydrogen Powered Transit Buses: Preliminary Evaluation Results  

SciTech Connect (OSTI)

This paper provides preliminary results from an evaluation by DOE's National Renewable Energy Laboratory of hydrogen-powered transit buses at SunLine Transit Agency.

Chandler, K.; Eudy, L.

2007-02-01T23:59:59.000Z

429

New York City Transit Hybrid and CNG Transit Buses: Interim Evaluation Results  

SciTech Connect (OSTI)

This report focuses on the evaluation of compressed natural gas (CNG) and diesel hybrid electric bus propulsion systems in New York City Transit's transit buses.

Chandler, K.; Eberts, E.; Eudy, L.

2006-01-01T23:59:59.000Z

430

Influence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared by Successive Ionic Layer Adsorption and  

E-Print Network [OSTI]

as 15% was achieved for perovskite-sensitized solar cells.7 As a derivative of dye-sensitized solarInfluence of Cationic Precursors on CdS Quantum-Dot-Sensitized Solar Cell Prepared by Successive (QDs) onto porous oxide films for quantum-dot-sensitized solar cell (QDSC) applications. In this work

Cao, Guozhong

431

An electrically driven quantum dot-in-nanowire visible single photon source operating up to 150 K  

SciTech Connect (OSTI)

We demonstrate electrically pumped single photon emission up to 150 K from a single InGaN quantum dot embedded in a GaN nanowire junction diode. The InGaN dot-in-nanowire p-n junctions were grown on silicon by molecular beam epitaxy. The exciton electroluminescence from individual dot-in-nanowires is in the green spectral range (? ? 520 nm) and is detectable up to 150 K. Second order autocorrelation measurements performed at the exciton energy at an ambient temperature of 125 K show a background corrected g{sup (2)}(0) equal to 0.35, indicating dominant single photon emission. The steady state nanowire temperature under these conditions is estimated to be 150 K due to Joule heating induced by the large nanowire series resistance. Time resolved photoluminescence measurements yield an exciton radiative lifetime of 1.1 ns.

Deshpande, Saniya; Bhattacharya, Pallab [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)] [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

2013-12-09T23:59:59.000Z

432

Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in a GaAs nanowire  

SciTech Connect (OSTI)

We demonstrate a highly uniform, dense stack of In{sub 0.22}Ga{sub 0.78}As/GaAs quantum dot (QD) structures in a single GaAs nanowire (NW). The size (and hence emission energy) of individual QD is tuned by careful control of the growth conditions based on a diffusion model of morphological evolution of NWs and optical characterization. By carefully tailoring the emission energies of individual QD, dot-to-dot inhomogeneous broadening of QD stacks in a single NW can be as narrow as 9.3?meV. This method provides huge advantages over traditional QD stack using a strain-induced Stranski-Krastanow growth scheme. We show that it is possible to fabricate up to 200 uniform QDs in single GaAs NWs using this growth technique without degradation of the photoluminescence intensity.

Tatebayashi, J., E-mail: tatebaya@iis.u-tokyo.ac.jp; Ota, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Ishida, S.; Nishioka, M.; Iwamoto, S.; Arakawa, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

2014-09-08T23:59:59.000Z

433

WVU Personal Rapid Transit Benefit Cost Analysis  

E-Print Network [OSTI]

WVU Personal Rapid Transit Benefit Cost Analysis Morgantown, West Virginia Prepared For: West ......................................................................... 12 Demographic Data Summary techniques suitable for assessing the impact of the WVU Personal Rapid Transit System (PRT) was employed

Mohaghegh, Shahab

434

Site Transition Plan Guidance, December 2004  

SciTech Connect (OSTI)

A short Department of Energy program document has been created to provide an outline on what the Site Transition Plan (STP) objectives are for the transition from the Office of Environmental Management to the newly established Office of Legacy Management.

none,

2004-12-01T23:59:59.000Z

435

Steps Toward a Successful Transition to  

E-Print Network [OSTI]

Steps Toward a Successful Transition to No-Till Sjoerd W. Duiker Soil Management Specialist, Penn .................................................................................. 3 Planning the transition to no ........................................................................ 12 Cover crop selection and management .............................................. 12 STEP 3

Kaye, Jason P.

436

Transit Infrastructure Finance Through Station Location Auctions  

E-Print Network [OSTI]

Numerous route and station options Strong real estate marketreal estate market Transit friendly constituents Numerous route and station options

Ian Carlton

2009-01-01T23:59:59.000Z

437

GaAs single quantum dot embedded into AlGaAs nanowire  

SciTech Connect (OSTI)

We report on a study of the photoluminescence spectra taken from quasi one-dimensional and quasi zero-dimensional semiconductor heterostructures. The structures were grown by molecular-beam epitaxy in (111) direction and were cylindrical nanowires based on AlGaAs, of 20 - 50 nm in diameter and 0.5 - 1 ?m in length. Inside the nanowires contain one or two GaAs quantum dots, of 2 nm thick and 15 - 45 nm in diameter. We studied a single nanowire. The photoluminescence and photoluminescence excitation spectra were registered as a function of the intensity of optical excitation.

Kochereshko, V. P.; Kats, V. N. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and Spin Optics Laboratory, Saint Petersburg State University, Ul'yanovskaya 1, Petrodvorets, St. Petersburg, 198904 (Russian Federation); Platonov, A. V. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg (Russian Federation); Cirlin, G. E.; Bouravleuv, A. D.; Samsonenko, Yu. B. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and St. Petersburg Academic University of the RAS Khlopina 8/3, 195220, St. Petersburg (Russian Federation); Besombes, L.; Mariette, H. [CEA-CNRS group Nanophysique et Semiconducteurs, CEA, INAC, SP2M, and Institut Néel, 17 rue des Martyrs, F-38054 Grenoble (France)

2013-12-04T23:59:59.000Z

438

Secondary treatment of films of colloidal quantum dots for optoelectronics and devices produced thereby  

DOE Patents [OSTI]

A method of forming an optoelectronic device. The method includes providing a deposition surface and contacting the deposition surface with a ligand exchange chemical and contacting the deposition surface with a quantum dot (QD) colloid. This initial process is repeated over one or more cycles to form an initial QD film on the deposition surface. The method further includes subsequently contacting the QD film with a secondary treatment chemical and optionally contacting the surface with additional QDs to form an enhanced QD layer exhibiting multiple exciton generation (MEG) upon absorption of high energy photons by the QD active layer. Devices having an enhanced QD active layer as described above are also disclosed.

Semonin, Octavi Escala; Luther, Joseph M; Beard, Matthew C; Chen, Hsiang-Yu

2014-04-01T23:59:59.000Z

439

Room temperature midinfrared electroluminescence from InSb/InAs quantum dot light emitting diodes  

SciTech Connect (OSTI)

Self-assembled InSb submonolayer quantum dots (QDs) in an InAs matrix have been grown by molecular beam epitaxy using Sb{sub 2} and As{sub 2} fluxes. The structures exhibit bright midinfrared photoluminescence up to room temperature. Intense room temperature electroluminescence with a peak at wavelength near 3.8 {mu}m was observed from p-i-n light emitting diode structures containing ten InSb submonolayer QD sheets inserted within the InAs active region.

Carrington, P. J.; Solov'ev, V. A.; Zhuang, Q.; Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom); Ivanov, S. V. [Ioffe Physico-Technical Institute, Polytekhnicheskaya 26, St. Petersburg 194021 (Russian Federation)

2008-09-01T23:59:59.000Z

440

Slow-light propagation using mode locking of spin precession in quantum dots  

SciTech Connect (OSTI)

We propose using mode locking to enable coherent nonlinear optical effects in inhomogenously broadened spin ensembles. We carry out detailed calculations for quantum dot systems in which increased spin coherence via mode locking has been recently observed [A. Greilich et al., Science 313, 341 (2006); 317, 1896 (2007)]. We show how, in the presence of spin locking, a strong pulse-matching effect occurs, providing a powerful tool for high-bandwidth linear optical processing. We then go on to study 'slow light' in this system and show that high-bandwidth pulses can be controllably delayed by a time comparable to the pulse width.

Shabaev, A. [George Mason University, Fairfax Virginia 22030 (United States); Dutton, Z. [Raytheon BBN Technologies, 10 Moulton Street, Cambridge, Massachusetts 02138 (United States); Naval Research Laboratory, Washington, D.C. 20375 (United States); Kennedy, T. A.; Efros, Al. L. [Naval Research Laboratory, Washington, D.C. 20375 (United States)

2010-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Self-frequency summing in quantum dot photonic crystal nanocavity lasers  

SciTech Connect (OSTI)

We demonstrate self-frequency summing in photonic crystal nanocavity lasers with quantum dot gain. Two dipole modes and a hexapole mode, supported in the cavity, simultaneously showed lasing oscillation in the near infrared wavelength region under optical carrier injection. Meanwhile, within the same laser cavity, the internally generated three laser fields are up-converted to exhibit sharp visible emission lines via intra-cavity nonlinear frequency summing (and doubling) processes. This self-frequency summing process in active nanocavities will pave the way for developing nanoscale nonlinear optical light sources.

Ota, Yasutomo; Watanabe, Katsuyuki [Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan)] [Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Iwamoto, Satoshi; Arakawa, Yasuhiko [Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan) [Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

2013-12-09T23:59:59.000Z

442

SiGe quantum dots for fast hole spin Rabi oscillations  

SciTech Connect (OSTI)

We report on hole g-factor measurements in three terminal SiGe self-assembled quantum dot devices with a top gate electrode positioned very close to the nanostructure. Measurements of both the perpendicular as well as the parallel g-factor reveal significant changes for a small modulation of the top gate voltage. From the observed modulations, we estimate that, for realistic experimental conditions, hole spins can be electrically manipulated with Rabi frequencies in the order of 100?MHz. This work emphasises the potential of hole-based nano-devices for efficient spin manipulation by means of the g-tensor modulation technique.

Ares, N.; Prager, A.; De Franceschi, S. [SPSMS/LaTEQS, CEA-INAC/UJF-Grenoble 1, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France)] [SPSMS/LaTEQS, CEA-INAC/UJF-Grenoble 1, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France); Katsaros, G. [SPSMS/LaTEQS, CEA-INAC/UJF-Grenoble 1, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France) [SPSMS/LaTEQS, CEA-INAC/UJF-Grenoble 1, 17 Rue des Martyrs, 38054 Grenoble Cedex 9 (France); Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Johannes Kepler University, Institute of Semiconductor and Solid State Physics, Altenbergerstr. 69, 4040 Linz (Austria); Golovach, V. N. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany) [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU) and Donostia International Physics Center DIPC, E-20018 San Sebastián (Spain); IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao (Spain); Zhang, J. J. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany)] [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Glazman, L. I. [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States)] [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Schmidt, O. G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany) [Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden (Germany); Center for Advancing Electronics Dresden, TU Dresden (Germany)

2013-12-23T23:59:59.000Z

443

Analysis of InAs/GaAs quantum dot solar cells using Suns-Voc measurements  

E-Print Network [OSTI]

. Appl. Phys. 32 (1961) 510. [10] G. Wei, K. Shiu, N.C. Giebink, S.R. Forrest, Thermodynamic limits of quantum photovoltaic cell efficiency, Appl. Phys. Lett. 91 (2007) 223507. [11] A. Martí, A. Luque, Comment on Thermodynamics limits of quantum photo... /GaAs quantum dot solar cells and the influence on the open circuit voltage, Appl. Phys. Lett. 97 (2010) 123505. [26] A. Martí, A. Luque, Next Generation Photovoltaics: High Efficiency Through Full Spectrum Utilization, IOP Publishing, Bristol, UK, 2004. [27] H...

Beattie, N. S.; Zoppi, G.; See, P.; Farrer, I.; Duchamp, M.; Morrison, D. J.; Miles, R. W.; Ritchie, D. A.

2014-08-06T23:59:59.000Z

444

Maximal tripartite entanglement between singlet-triplet qubits in quantum dots  

E-Print Network [OSTI]

Singlet-triplet states in double quantum dots are promising realizations of qubits, and capacitive coupling can be used to create entanglement between these qubits. We propose an entangling three-qubit gate of singlet-triplet qubits in a triangular setup. Our simulations using a realistic microscopic model show that a maximally entangled Greenberger-Horne-Zeilinger state can be generated as the qubits are evolved under exchange. Furthermore, our analysis for the gate operation can be used to extract the actual experimental pulse sequence needed to realize this.

Tuukka Hiltunen; Ari Harju

2013-10-24T23:59:59.000Z

445

High performance continuous wave 1.3??m quantum dot lasers on silicon  

SciTech Connect (OSTI)

We demonstrate record performance 1.3??m InAs quantum dot lasers grown on silicon by molecular beam epitaxy. Ridge waveguide lasers fabricated from the as-grown material achieve room temperature continuous wave thresholds as low as 16?mA, output powers exceeding 176 mW, and lasing up to 119?°C. P-modulation doping of the active region improves T{sub 0} to the range of 100–200?K while maintaining low thresholds and high output powers. Device yield is presented showing repeatable performance across different dies and wafers.

Liu, Alan Y., E-mail: ayliu01@engineering.ucsb.edu; Norman, Justin [Materials Department, University of California Santa Barbara, California 93106 (United States); Zhang, Chong [Department of Electrical and Computer Engineering, University of California Santa Barbara, California 93106 (United States); Snyder, Andrew; Lubyshev, Dmitri; Fastenau, Joel M.; Liu, Amy W. K. [IQE, Inc., Bethlehem, Pennsylvania 18015 (United States); Gossard, Arthur C.; Bowers, John E. [Materials Department, University of California Santa Barbara, California 93106 (United States); Department of Electrical and Computer Engineering, University of California Santa Barbara, California 93106 (United States)

2014-01-27T23:59:59.000Z

446

Solution-processed high-performance colloidal quantum dot tandem photodetectors on flexible substrates  

SciTech Connect (OSTI)

We report a high-performance colloidal quantum dot (CQD)-based near-infrared tandem photodetector fabricated on flexible substrates via solution-processed method. The tandem photodetector on poly(ethylene terephthalate) substrates exhibited low dark current and high detectivities over ?8.8?×?10{sup 11} Jones at near infrared range at ?0.5?V bias and over ?10{sup 13} Jones near 0 bias. The critical bend radii of ?8?mm and ?3?mm have been demonstrated for tensile and compressive bending, respectively. The performance of photodetectors remains stable under mechanical stress, making PbSe CQD material a promise candidate for flexible infrared sensing applications.

Jiang, Zhenyu; You, Guanjun; Wang, Li; Liu, Jie; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Hu, Wenjia [China Tianchen Engineering Corporation, Tianjin 300400 (China); Zhang, Yu [State Key Laboratory on Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China)

2014-08-28T23:59:59.000Z

447

On-chip single photon sources based on quantum dots in photonic crystal structures  

E-Print Network [OSTI]

of this dissertation have appeared or will appear in form of the following journal articles and contributed talks at international conferences. Articles A. Schwagmann, S. Kalliakos, I. Farrer, J. P. Griffiths, G. A. C. Jones, D. A. Ritchie, and A. J. Shields. “On... -chip single photon emission from an integrated semiconductor quantum dot into a photonic crystal waveguide.” Applied Physics Letters 99, 261108 (2011). A. Schwagmann, S. Kalliakos, D. J. P. Ellis, I. Farrer, J. P. Griffiths, G. A. C. Jones, D. A. Ritchie...

Schwagmann, Andre

2013-02-05T23:59:59.000Z

448

Nonlinear Temporal Dynamics of Strongly Coupled Quantum Dot-Cavity System  

E-Print Network [OSTI]

We theoretically analyze and simulate the temporal dynamics of strongly coupled quantum dot-cavity system driven by a resonant laser pulse. We observe the signature of Rabi oscillation in the time resolved response of the system (i.e., in the numerically calculated cavity output), derive simplified linear and non-linear semi-classical models that approximate well the system's behavior in the limits of high and low power drive pulse, and describe the role of quantum coherence in the exact dynamics of the system. Finally, we also present experimental data showing the signature of the Rabi oscillation in time domain.

Arka Majumdar; Dirk Englund; Michal Bajcsy; Jelena Vuckovic

2011-10-20T23:59:59.000Z

449

An intentionally positioned (In,Ga)As quantum dot in a micron sized light emitting diode  

SciTech Connect (OSTI)

We have integrated individual (In,Ga)As quantum dots (QDs) using site-controlled molecular beam epitaxial growth into the intrinsic region of a p-i-n junction diode. This is achieved using an in situ combination of focused ion beam prepatterning, annealing, and overgrowth, resulting in arrays of individually electrically addressable (In,Ga)As QDs with full control on the lateral position. Using microelectroluminescence spectroscopy we demonstrate that these QDs have the same optical quality as optically pumped Stranski-Krastanov QDs with random nucleation located in proximity to a doped interface. The results suggest that this technique is scalable and highly interesting for different applications in quantum devices.

Mehta, M.; Michaelis de Vasconcellos, S.; Zrenner, A.; Meier, C. [Department of Physics and Center for Optoelectronics and Photonics Paderborn (CeOPP), University of Paderborn, Warburger Street 100, 33098 Paderborn (Germany); Reuter, D.; Wieck, A. D. [Applied Solid State Physics, Ruhr-University of Bochum, Universitaetsstr. 150, 44780 Bochum (Germany)

2010-10-04T23:59:59.000Z

450

Effect of internal electric field on InAs/GaAs quantum dot solar cells  

SciTech Connect (OSTI)

We studied time-resolved carrier recombination in InAs/GaAs quantum dot (QD) solar cells. The electric field in a p-i-n diode structure spatially separates photoexcited carriers in QDs, strongly affecting the conversion efficiency of intermediate-band solar cells. The radiative decay lifetime is dramatically reduced in a strong electric field (193?kV/cm) by efficient recombination due to strong carrier localization in each QD and significant tunneling-assisted electron escape. Conversely, an electric field of the order of 10?kV/cm maintains electronic coupling in the stacked QDs and diminishes tunneling-assisted electron escape.

Kasamatsu, Naofumi; Kada, Tomoyuki; Hasegawa, Aiko; Harada, Yukihiro; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

2014-02-28T23:59:59.000Z

451

Site control technique for quantum dots using electron beam induced deposition  

SciTech Connect (OSTI)

To develop simple and high throughput sit definition technique for quantum dots (QDs), the electron beam induced deposition (EBID) method was used as desorption guide of phosphorus atoms form InP substrate. As the results one or a few indium (In) droplets (DLs) were created in the carbon grid pattern by thermal annealing at a temperature of 450°C for 10 min in the ultra high vacuum condition. The size of In DLs was larger than QDs, but arsenide DLs by molecular beam in growth chamber emitted wavelength of 1.028?m at 50K by photoluminescence measurement.

Iizuka, Kanji; Jung, JaeHun; Yokota, Hiroshi [Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro, Minami-saitama, Saitama 3458501 (Japan)

2014-05-15T23:59:59.000Z

452

Direct Patterning of CdSe Quantum Dots into Sub-100 nm Structures  

SciTech Connect (OSTI)

Ordered, two-dimensional cadmium selenide (CdSe) arrays have been fabricated on indium-doped tin oxide (ITO) electrodes using the pattern replication in nonwetting templates (PRINT) process. CdSe quantum dots (QDs) with an average diameter of 2.7 nm and a pyridine surface ligand were used for patterning. The PRINT technique utilizes a perfluoropolyether (PFPE) elastomeric mold that is tolerant of most organic solvents, thus allowing solutions of CdSe QDs in 4-picoline to be used for patterning without significant deformation of the mold. Nanometer-scale diffraction gratings have been successfully replicated with CdSe QDs.

Hampton, Meredith J.; Templeton, Joseph L.; DeSimone, Joseph M.

2010-01-01T23:59:59.000Z

453

UltraDots Inc formely UltraPhotonics | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-gTagusparkCalculator Jump to: navigation,UTEKUlster County, NewUltraDots

454

Quantum Dot Tracers for Use in Engineered Geothermal | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion | Department ofT ib l L dDepartment of EnergyQualifiedQualityTransfer ofQuantum Dot

455

DOT Offers nearly $25 Million for More Zero-Emission Buses | Department of  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in Review: TopEnergy DOE Theory9-9260-2003October 02,(July 2013)Energy DOT Offers

456

Mid infrared optical properties of Ge/Si quantum dots with different doping level  

SciTech Connect (OSTI)

Optical characterization of the Ge/Si quantum dots using equilibrium and photo-induced absorption spectroscopy in the mid-infrared spectral range was performed in this work. Equilibrium absorption spectra were measured in structures with various doping levels for different light polarizations. Photo-induced absorption spectra measured in undoped structure under interband optical excitation of non-equilibrium charge carriers demonstrate the same features as doped sample in equilibrium conditions. Hole energy spectrum was determined from the analysis of experimental data.

Sofronov, A. N.; Firsov, D. A.; Vorobjev, L. E.; Shalygin, V. A.; Panevin, V. Yu.; Vinnichenko, M. Ya. [St. Petersburg State Polytechnic University, Polytechnicheskaya str. 29, St. Petersburg (Russian Federation); Tonkikh, A. A. [Max Planck Institute of Microstructure Physics, Weinberg 2 D-06120, Halle (Saale) (Germany); Danilov, S. N. [University of Regensburg, Regensburg (Germany)

2013-12-04T23:59:59.000Z

457

Transition Radiation in QCD matter  

E-Print Network [OSTI]

In ultrarelativistic heavy ion collisions a finite size QCD medium is created. In this paper we compute radiative energy loss to zeroth order in opacity by taking into account finite size effects. Transition radiation occurs on the boundary between the finite size medium and the vacuum, and we show that it lowers the difference between medium and vacuum zeroth order radiative energy loss relative to the infinite size medium case. Further, in all previous computations of light parton radiation to zeroth order in opacity, there was a divergence caused by the fact that the energy loss is infinite in the vacuum and finite in the QCD medium. We show that this infinite discontinuity is naturally regulated by including the transition radiation.

Magdalena Djordjevic

2005-12-22T23:59:59.000Z

458

Articulated transition duct in turbomachine  

DOE Patents [OSTI]

Turbine systems are provided. A turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion and a downstream portion. The upstream portion extends from the inlet between an inlet end and an aft end. The downstream portion extends from the outlet between an outlet end and a head end. The turbine system further includes a joint coupling the aft end of the upstream portion and the head end of the downstream portion together. The joint is configured to allow movement of the upstream portion and the downstream portion relative to each other about or along at least one axis.

Flanagan, James Scott; McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Pentecost, Ronnie Ray

2014-04-29T23:59:59.000Z

459

An Automobile/Transit Emissions Evaluation of Southern California's Metrolink  

E-Print Network [OSTI]

percentile) Finn| Report: An Automobile~Transit EmissionsAn Automobile/Transit Emissions Evaluation of Southernregulation. or An Automobile/Transit Emissions Evaluation of

Barth, Matthew J.; Tadi, Ramakrishna R.

1995-01-01T23:59:59.000Z

460

SCATTERING BEHAVIOR OF TRANSITIONAL SHOCK WAVES  

E-Print Network [OSTI]

SCATTERING BEHAVIOR OF TRANSITIONAL SHOCK WAVES Kevin R. Zumbrun Bradley J. Plohr Dan Marchesin September, 1991 Abstract. We study the stability and asymptotic behavior of transitional shock waves as solutions of a parabolic system of conservation laws. In contrast to classical shock waves, transitional

New York at Stoney Brook, State University of

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

KEYNOTE ADDRESS ECONOMIES IN TRANSITION: SOME ASPECTS  

E-Print Network [OSTI]

couple of days, with my focus on transition economies and environmental management in this neighborhoodKEYNOTE ADDRESS ECONOMIES IN TRANSITION: SOME ASPECTS OF ENVIRONMENTAL POLICY Jeffrey Sachs. Tel: (617) 495-5999. Fax: (617) 495-0527. #12;2 Keynote Address Economies in Transition: Some Aspects

462

Moving Ahead: From Transition to Transformation  

E-Print Network [OSTI]

political stability. This chapter briefly discusses the important elements of `management of transition' and components of `transformation' of the old state into a new nation. 9.2 Managing Transition It is crucially important to smoothly manage transition to achieve stability and democracy, and materialise transformation

Richner, Heinz

463

State and Transition Modeling History & Current Concepts  

E-Print Network [OSTI]

management input · Friedel(1991) concentrated on thresholds ­ "...compatible with state and transition theoryState and Transition Modeling History & Current Concepts Tamzen K. Stringham Oregon State vegetation change #12;· Non-equilibrium Models (States, Transitions and Thresholds) ­ Encompass Range

464

Liquid-phase plasma synthesis of silicon quantum dots embedded in carbon matrix for lithium battery anodes  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • Silicon quantum dots embedded in carbon matrix (SiQDs/C) were fabricated. • SiQDs/C exhibits excellent battery performance as anode materials with high specific capacity. • The good performance was attributed to the marriage of small sized SiQDs and carbon. - Abstract: Silicon quantum dots embedded in carbon matrix (SiQDs/C) nanocomposites were prepared by a novel liquid-phase plasma assisted synthetic process. The SiQDs/C nanocomposites were demonstrated to show high specific capacity, good cycling life and high coulmbic efficiency as anode materials for lithium-ion battery.

Wei, Ying [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); College of Chemistry and Chemical Engineering, Bohai University, Jinzhou 121000 (China); Yu, Hang; Li, Haitao; Ming, Hai; Pan, Keming; Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China)

2013-10-15T23:59:59.000Z

465

Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots  

E-Print Network [OSTI]

In this chapter we review the use of spins in optically-active InAs quantum dots as the key physical building block for constructing a quantum repeater, with a particular focus on recent results demonstrating entanglement between a quantum memory (electron spin qubit) and a flying qubit (polarization- or frequency-encoded photonic qubit). This is a first step towards demonstrating entanglement between distant quantum memories (realized with quantum dots), which in turn is a milestone in the roadmap for building a functional quantum repeater. We also place this experimental work in context by providing an overview of quantum repeaters, their potential uses, and the challenges in implementing them.

McMahon, Peter L

2015-01-01T23:59:59.000Z

466

Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots  

E-Print Network [OSTI]

In this chapter we review the use of spins in optically-active InAs quantum dots as the key physical building block for constructing a quantum repeater, with a particular focus on recent results demonstrating entanglement between a quantum memory (electron spin qubit) and a flying qubit (polarization- or frequency-encoded photonic qubit). This is a first step towards demonstrating entanglement between distant quantum memories (realized with quantum dots), which in turn is a milestone in the roadmap for building a functional quantum repeater. We also place this experimental work in context by providing an overview of quantum repeaters, their potential uses, and the challenges in implementing them.

Peter L. McMahon; Kristiaan De Greve

2015-01-14T23:59:59.000Z

467

Transition physics and scaling overview  

SciTech Connect (OSTI)

This paper presents an overview of recent experimental progress towards understanding H-mode transition physics and scaling. Terminology and techniques for studying H-mode are reviewed and discussed. The model of shear E x B flow stabilization of edge fluctuations at the L-H transition is gaining wide acceptance and is further supported by observations of edge rotation on a number of new devices. Observations of poloidal asymmetries of edge fluctuations and dephasing of density and potential fluctuations after the transition pose interesting challenges for understanding H-mode physics. Dedicated scans to determine the scaling of the power threshold have now been performed on many machines. A dear B{sub t} dependence is universally observed but dependence on the line averaged density is complicated. Other dependencies are also reported. Studies of the effect of neutrals and error fields on the power threshold are under investigation. The ITER threshold database has matured and offers guidance to the power threshold scaling issues relevant to next-step devices.

Carlstrom, T.N.

1995-12-01T23:59:59.000Z

468

Proposal of high efficiency solar cells with closely stacked InAs/In{sub 0.48}Ga{sub 0.52}P quantum dot superlattices: Analysis of polarized absorption characteristics via intermediate–band  

SciTech Connect (OSTI)

We present a theoretical study of the electronic structures and polarized absorption properties of quantum dot superlattices (QDSLs) using wide–gap matrix material, InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs, for realizing intermediate–band solar cells (IBSCs) with two–step photon–absorption. The plane–wave expanded Burt–Foreman operator ordered 8–band k·p theory is used for this calculation, where strain effect and piezoelectric effect are taken into account. We find that the absorption spectra of the second transitions of two–step photon–absorption can be shifted to higher energy region by using In{sub 0.48}Ga{sub 0.52}P, which is lattice–matched material to GaAs substrate, as a matrix material instead of GaAs. We also find that the transverse magnetic polarized absorption spectra in InAs/In{sub 0.48}Ga{sub 0.52}P QDSL with a separate IB from the rest of the conduction minibands can be shifted to higher energy region by decreasing the QD height. As a result, the second transitions of two–step photon–absorption by the sunlight occur efficiently. These results indicate that InAs/In{sub 0.48}Ga{sub 0.52}P QDSLs are suitable material combination of IBSCs toward the realization of ultrahigh efficiency solar cells.

Yoshikawa, H., E-mail: yoshikawa-hirofumi@sharp.co.jp; Kotani, T.; Kuzumoto, Y.; Izumi, M.; Tomomura, Y.; Hamaguchi, C. [Advanced Technology Research Laboratories, Sharp Corporation Tenri, Nara 632-8567 (Japan)

2014-07-07T23:59:59.000Z

469

Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting  

SciTech Connect (OSTI)

With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices.

James Perkins; Matthew Stevenson; Gagan Mahan; Seth Coe-Sullivan; Peter Kazlas

2011-01-21T23:59:59.000Z

470

Theoretical simulation of carrier capture and relaxation rates in quantum-dot semiconductor optical amplifiers  

SciTech Connect (OSTI)

Based on Auger scattering mechanism, carrier-carrier scattering dynamics between the two-dimensional carrier reservoir (also called wetting layer, i.e., WL) and the confined quantum dot ground and first excited state in quantum-dot semiconductor optical amplifiers (QD-SOAs) are investigated theoretically in this paper. The scattering rates for independent electron and hole densities are calculated. The results show an ultra-fast carrier capture (relaxation) rate up to 1 ps{sup ?1}, and there is a complex dependence of the Coulomb scattering rates on the WL electron and hole densities. In addition, due to the different effective mass and the level distribution, the scattering rates for electron and hole are very different. Finally, in order to provide a direction to control (increase or decrease) the input current in realistic QD-SOA systems, a simple method is proposed to determine the trends of the carrier recovery rates with the WL carrier densities in the vicinity of the steady-state.

Wu, Yunhu [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Department of Physics, Kashi Normal College, Kashi 844006 (China); Zhang, Guoping, E-mail: gpzhang@phy.ccnu.edu.cn [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Guo, Ling; Qi, Guoqun [Department of Physics, Kashi Normal College, Kashi 844006 (China); Li, Xiaoming [Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)

2014-06-14T23:59:59.000Z

471

Revolutionary Method for Increasing the Efficiency of White Light Quantum Dot LEDs  

SciTech Connect (OSTI)

Covering a light-emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non-uniform distribution of QDs, which respec-tively diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal proc-essing (PTP), reduces the number of point defects while main-taining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of the quantum dot nanoparticles. The cur-rent research uses a thermal model to predict annealing tempera-tures during PTP and demonstrates up to a 300% increase in pho-toluminescence for QDs on passive substrates

Duty, Chad E [ORNL; Bennett, Charlee J C [ORNL; Sabau, Adrian S [ORNL; Jellison Jr, Gerald Earle [ORNL; Boudreaux, Philip R [ORNL; Walker, Steven C [ORNL; Ott, Ronald D [ORNL

2011-01-01T23:59:59.000Z

472

Theory of Linear Optical Absorption in Diamond Shaped Graphene Quantum Dots  

E-Print Network [OSTI]

In this paper, optical and electronic properties of diamond shaped graphene quantum dots (DQDs) have been studied by employing large-scale electron-correlated calculations. The computations have been performed using the $\\pi$-electron Pariser-Parr-Pople model Hamiltonian, which incorporates long-range Coulomb interactions. The influence of electron-correlation effects on the ground and excited states has been included by means of the configuration-interaction approach, used at various levels. Our calculations have revealed that the absorption spectra are red-shifted with the increasing sizes of quantum dots. It has been observed that the first peak of the linear optical absorption, which represents the optical gap, is not the most intense peak. This result is in excellent agreement with the experimental data, but in stark contrast to the predictions of the tight-binding model, according to which the first peak is the most intense peak, pointing to the importance of electron-correlation effects. Furthermore, a...

Basak, Tista; Shukla, Alok

2015-01-01T23:59:59.000Z

473

Shim for sealing transition pieces  

DOE Patents [OSTI]

According to one aspect of the invention, a shim for sealing two adjacent turbine transition pieces is disclosed. The shim includes a circumferential member that includes a first lateral flange and a second lateral flange. Further, the first and second lateral flanges each comprise a tab configured to mate to a first surface plane and the first and second lateral flanges are configured to mate to a second surface plane, wherein the first and second surface planes are substantially parallel. In addition, the shim includes a first flange extending substantially perpendicular from the circumferential member.

Lacy, Benjamin Paul (Greer, SC); Demiroglu, Mehmet (Troy, NY); Sarawate, Neelesh Nandkumar (Niskayuna, NY)

2012-07-24T23:59:59.000Z

474

Approximating Metal-Insulator Transitions  

E-Print Network [OSTI]

We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate metal-insulator transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges which are at variance to the celebrated Aubry-Andre model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase similar to the divergence of the localization length in the insulating phase.

C. Danieli; K. Rayanov; B. Pavlov; G. Martin; S. Flach

2014-05-06T23:59:59.000Z

475

Low floor mass transit vehicle  

DOE Patents [OSTI]

A mass transit vehicle includes a frame structure that provides an efficient and economical approach to providing a low floor bus. The inventive frame includes a stiff roof panel and a stiff floor panel. A plurality of generally vertical pillars extend between the roof and floor panels. A unique bracket arrangement is disclosed for connecting the pillars to the panels. Side panels are secured to the pillars and carry the shear stresses on the frame. A unique seating assembly that can be advantageously incorporated into the vehicle taking advantage of the load distributing features of the inventive frame is also disclosed.

Emmons, J. Bruce (Beverly Hills, MI); Blessing, Leonard J. (Rochester, MI)

2004-02-03T23:59:59.000Z

476

Even more Oak Ridge transitions  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicy and Assistance100 tonusing ARMEven more Oak Ridge transitions The

477

High efficiency photodetectors fabricated by electrostatic layer-by-layer self-assembly of CdTe quantum dots  

E-Print Network [OSTI]

High efficiency photodetectors fabricated by electrostatic layer-by-layer self-assembly of CdTe 20 October 2008 We demonstrate high-performance photodetectors from multilayers of CdTe quantum dots. The synthesis of CdTe QDs in aqueous solution using cadmium perchlorate hydrate and Al2Te3 was previously re

Lin, Lih Y.

478

InAs(ZnCdS) Quantum Dots Optimized for Biological Imaging in the Near-Infrared  

E-Print Network [OSTI]

We present the synthesis of InAs quantum dots (QDs) with a ZnCdS shell with bright and stable emission in the near-infrared (NIR, 700?900 nm) region for biological imaging applications. We demonstrate how NIR QDs can image ...

Allen, Peter M.

479

Visualizing and Quantifying Molecular Goodness-of-Fit: Small-probe Contact Dots with Explicit Hydrogen Atoms  

E-Print Network [OSTI]

Visualizing and Quantifying Molecular Goodness-of-Fit: Small-probe Contact Dots with Explicit) for analyzing interaction patterns in the molecules themselves. # 1999 Academic Press Keywords: protein internal, 1711±1733 0022-2836/99/041711±23 $30.00/0 # 1999 Academic Press #12;Introduction Remarkably ordered

Richardson, David

480

Solution Processed Tungsten Oxide Interfacial Layer for Efficient Hole-Injection in Quantum Dot Light-Emitting Diodes  

E-Print Network [OSTI]

2/2014 Solution Processed Tungsten Oxide Interfacial Layer for Efficient Hole-Injection in Quantum Layer for Efficient Hole-Injection in Quantum Dot Light- Emitting Diodes Xuyong Yang, Evren Mutlugun-based devices, the organic interfacial buffer layers have inferior thermal stability. Efforts to replace PEDOT

Demir, Hilmi Volkan

Note: This page contains sample records for the topic "gray dots transitioning" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Reversible Modification of CdSe-CdS/ZnS Quantum Dot Fluorescence by Surrounding Ca2+  

E-Print Network [OSTI]

Reversible Modification of CdSe-CdS/ZnS Quantum Dot Fluorescence by Surrounding Ca2+ Ions Li Li (3-MPA) coated CdSe-CdS/ZnS core-multishell QDs when free Ca2+ ions were added to and subsequently removed from the QD solution. It was found that QD fluorescence intensity was reduced when Ca2+ ions were

Haviland, David

482

Suppressed Blinking and Auger Recombination in Near-Infrared Type-II InP/CdS Nanocrystal Quantum Dots  

E-Print Network [OSTI]

Dots Allison M. Dennis, Benjamin D. Mangum, Andrei Piryatinski, Young-Shin Park, Daniel C. Hannah*, Materials Physics & Applications Division: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States Theoretical Division, Los Alamos National Laboratory

483

The dynamics of tunneling into self-assembled InAs dots R. J. Luyken, A. Lorke,a)  

E-Print Network [OSTI]

-defined, nanometer-size quantum dots with sizes in the 10 nm range.1 These systems are of great interest, not only for studying the basic properties of man-made ``artificial atoms,'' but also because of possible device, this degeneracy is lifted by electron­electron interactions, so that groups of charging peaks appear, which

Ludwig-Maximilians-Universität, München

484

A level set simulation for ordering of quantum dots via cleaved-edge X. B. Niu,1,2  

E-Print Network [OSTI]

applications such as next generation optoelectronic devices.1 For optimal performance of arrays of QDs it is ideal if the size distribution of the dots is rather uniform. Moreover, the exact properties of QDs can energy Etrans is sketched in Fig. 2. Within the method, island boundaries are described by a level set

Ratsch, Christian

485

Modeling Spike Trains from Area This chapter describes the application of a motion energy model to the dynamic dot  

E-Print Network [OSTI]

74 Chapter 6 Modeling Spike Trains from Area MT This chapter describes the application of a motion energy model to the dynamic dot stimulus. We wanted to know whether the precise temporal modulation widely compared to electrophysiological data from both area MT and its V1 inputs (Heeger, 1987; Grzywacz

Bair, Wyeth

486

Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures  

E-Print Network [OSTI]

Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures T. Shapoval,1,* V. Metlushko,2 M. Wolf,1 B. Holzapfel,1 V. Neu,1, Illinois 60612, USA Received 13 November 2009; published 11 March 2010 Strong pinning of superconducting

Metlushko, Vitali

487

PHYSICAL REVIEW E 85, 031117 (2012) Stochastically driven single-level quantum dot: A nanoscale finite-time thermodynamic  

E-Print Network [OSTI]

as a nanoscale finite-time thermodynamic machine. The dot is driven by an external stochastic force that switches that extracts heat from the cold reservoir via the work input of the stochastic driving. The efficiency coupling conditions, familiar features are recovered in appropriate limits: Carnot efficiency

Lindenberg, Katja

2012-01-01T23:59:59.000Z

488

Phonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu, and Alexander A. Balandina  

E-Print Network [OSTI]

or polycrystalline materials in terms of thermal transport. © 2005 American Institute of Physics. DOI: 10 strongly depends on interface conditions, is considered as a major thermal resistive mecha- nismPhonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu

489

IEEE TRANSACTIONS ON INFORMATION TECHNOLOGY IN BIOMEDICINE, VOL. 11, NO. 4, JULY 2007 443 Segmentation and Classification of Dot  

E-Print Network [OSTI]

Yeshaya Abstract--Signal segmentation and classification of fluorescence in situ hybridization (FISH classifier (NBC) or a multilayer perceptron is accomplished. When applied to a FISH image database, dot hybridization (FISH), image segmentation, multilayer perceptron (MLP), naive Bayesian classifier (NBC). I

Lerner, Boaz

490

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

SciTech Connect (OSTI)

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.

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)

2012-05-15T23:59:59.000Z

491

Long-time electron spin storage via dynamical suppression of hyperfine-induced decoherence in a quantum dot  

E-Print Network [OSTI]

by the nuclear spin environment in a quantum dot can be substantially increased by subjecting the electron and characterized. The impact of system and control nonidealities is also assessed, including the effect.125336 PACS number s : 03.67.Pp, 03.65.Yz, 75.10.Jm, 02.60.Cb I. INTRODUCTION Electron and nuclear spin

492

PHYSICAL REVIEW B 83, 155302 (2011) Size dependence of carrier dynamics and carrier multiplication in PbS quantum dots  

E-Print Network [OSTI]

in semiconductor QDs and its potential implications on highly efficient solar energy conversion. Nevertheless, many and carrier-multiplication efficiencies in PbS quantum dots (QDs) are investigated. In particular, we report that the carrier-multiplication energy efficiency increases with decreasing QD size. By comparing to theoretical

Van Stryland, Eric

493

Excitonic enhancement of nonradiative energy transfer from a quantum well in the optical near field of energy gradient quantum dots  

E-Print Network [OSTI]

. Phys. 111, 113714 (2012) Transport of indirect excitons in a potential energy gradient Appl. Phys. Lett 30 April 2012; published online 13 June 2012) We report strong exciton migration with an efficiency (QWs) to colloidal nanocrystal quantum dots (NQDs) is criti- cal to the energy efficiency in hybrid

Demir, Hilmi Volkan

494

Hybrid molecular assemblies composed of hydrogenase enzymes and quantum dots helps to pave the way for the  

E-Print Network [OSTI]

% wastepaper, including 10% post consumer waste. Lighting Up Enzymes for Solar Hydrogen Production NREL. Scientists at the National Renewable Energy Laboratory (NREL) have combined quan- tum dots, which selectivity and fast turnover of hydrogenase enzymes to achieve light-driven hydrogen (H2) production

495

Transitional nuclei near shell closures  

SciTech Connect (OSTI)

High spin states in Bismuth and Thallium nuclei near the Z = 82 shell closure and Cesium nuclei near the N = 82 shell closure in A = 190 and A = 130 regions, respectively, have been experimentally investigated using heavy-ion fusion evaporation reaction and by detecting the gamma rays using the Indian National Gamma Array (INGA). Interesting shape properties in these transitional nuclei have been observed. The results were compared with the neighboring nuclei in these two regions. The total Routhian surface (TRS) calculations have been performed for a better understanding of the observed properties. In mass region A = 190, a change in shape from spherical to deformed has been observd around neutron number N = 112 for the Bi (Z = 83) isotopes with proton number above the magic gap Z = 82, whereas, the shape of Tl (Z = 81) isotopes with proton number below the magic gap Z = 82 remains stable as a function of neutron number. An important transition from aplanar to planar configuration of angular momentum vectors leading to the occurance of nuclar chirality and magnetic rotation, respectively, has been proposed for the unique parity ?h{sub 11/2}??h{sub 11/2} configuration in Cs isotopes in the mass region A ? 130 around neutron number N = 79. These results are in commensurate with the TRS calculations.

Mukherjee, G. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064 (India); Pai, H. [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700064, India and Present Address: Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany)

2014-08-14T23:59:59.000Z

496

Study of the growth mechanisms of GaN/(Al, Ga)N quantum dots: Correlation between structural and optical properties  

SciTech Connect (OSTI)

The ammonia-based molecular beam epitaxy of GaN/(Al, Ga)N quantum dots is investigated using reflection high-energy electron diffraction, atomic force microscopy, transmission electron microscopy and photoluminescence. The main steps of the formation kinetics are identified and the influence of diffusion and evaporation processes on both the quantum dot and the wetting layer morphology is addressed. The correlation between the optical and structural properties of such structures finally allows for the analysis of matter exchanges between the quantum dots and the wetting layer during capping.

Sergent, S. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Universite de Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Damilano, B.; Huault, T.; Brault, J.; Tottereau, O.; Vennegues, P.; Leroux, M.; Semond, F.; Massies, J. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Korytov, M.

2011-03-01T23:59:59.000Z

497

Alameda-Contra Costa Transit District (AC Transit) Fuel Cell Transit Buses: Third Evaluation Report and Appendices  

SciTech Connect (OSTI)

This report describes operations at Alameda-Contra Costa Transit district for three protoype fuel cell buses and six diesel buses operating from the same location.

Chandler, K.; Eudy, L.

2008-07-01T23:59:59.000Z

498

Capping layer growth rate and the optical and structural properties of GaAsSbN-capped InAs/GaAs quantum dots  

SciTech Connect (OSTI)

Changing the growth rate during the heteroepitaxial capping of InAs/GaAs quantum dots (QDs) with a 5?nm-thick GaAsSbN capping layer (CL) strongly modifies the QD structural and optical properties. A size and shape transition from taller pyramids to flatter lens-shaped QDs is observed when the CL growth rate is decreased from 1.5 to 0.5 ML/s. This indicates that the QD dissolution processes taking place during capping can be controlled to some extent by the GaAsSbN CL growth rate, with high growth rates allowing a complete preservation of the QDs. However, the dissolution processes are shown to have a leveling effect on the QD height, giving rise to a narrower size distribution for lower growth rates. Contrary to what could be expected, these effects are opposite to the strong blue-shift and improvement of the photoluminescence (PL) observed for higher growth rates. Nevertheless, the PL results can be understood in terms of the strong impact of the growth rate on the Sb and N incorporation into the CL, which results in lower Sb and N contents at higher growth rates. Besides the QD-CL band offsets and QD strain, the different CL composition alters the band alignment of the system, which can be transformed to type-II at low growth rates. These results show the key role of the alloyed CL growth parameters on the resulting QD properties and demonstrate an intricate correlation between the PL spectra and the sample morphology in complex QD-CL structures.

Ulloa, J. M., E-mail: jmulloa@isom.upm.es; Utrilla, A. D.; Guzman, A.; Hierro, A. [Institute for Systems based on Optoelectronics and Microtechnology (ISOM) and Dpto. Ingeniería Electrónica, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Reyes, D. F.; Ben, T.; González, D. [Departamento de Ciencia de los Materiales e IM y QI, Universidad de Cádiz, 11510 Puerto Real (Cádiz) (Spain)

2014-10-07T23:59:59.000Z

499

Analysis of Nuclear Quantum Phase Transitions  

SciTech Connect (OSTI)

A microscopic analysis, based on nuclear energy density functionals, is presented for shape phase transitions in Nd isotopes. Low-lying excitation spectra and transition probabilities are calculated starting from a five-dimensional Hamiltonian, with parameters determined by constrained relativistic mean-field calculations for triaxial shapes. The results reproduce available data, and show that there is an abrupt change of structure at N = 90, that corresponds to a first-order quantum phase transition between spherical and axially deformed shapes.

Li, Z. P.; Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Niksic, T.; Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb (Croatia); Lalazissis, G. A. [Department of Theoretical Physics, Aristotle University of Thessaloniki, GR-54124 (Greece); Ring, P. [Physik-Department der Technischen Universitaet Muenchen, D-85748 Garching (Germany)

2009-08-26T23:59:59.000Z

500

Subcritical Fluctuations at the Electroweak Phase Transition  

E-Print Network [OSTI]

We study the importance of thermal fluctuations during the electroweak phase transition. We evaluate in detail the equilibrium number density of large amplitude subcritical fluctuations and discuss the importance of phase mixing to the dynamics of the phase transition. Our results show that, for realistic Higgs masses, the phase transition can be completed by the percolation of the true vacuum, induced by the presence of subcritical fluctuations.

Rudnei O. Ramos

1996-07-24T23:59:59.000Z