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Sample records for energy converterby mbe

  1. Fabrication of photovoltaic laser energy converterby MBE

    NASA Technical Reports Server (NTRS)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  2. Determination of composition and energy gaps of GaInNAsSb layers grown by MBE

    NASA Astrophysics Data System (ADS)

    Aho, A.; Korpijärvi, V.-M.; Isoaho, R.; Malinen, P.; Tukiainen, A.; Honkanen, M.; Guina, M.

    2016-03-01

    We present a method to accurately determine the composition of GaInNAsSb heterostructures and a modified band anti-crossing model to calculate the corresponding bandgaps. The composition determination method is based on combining x-ray diffractometry and energy dispersive x-ray spectroscopy measurements. The modified band anti-crossing model was derived from the model known for GaInNAs and using band-gap composition relations for GaInAs, GaInSb, InAsSb and GaAsSb. The model parameters were defined by fitting with experimental bandgap data retrieved from photoluminescence. For validation and data fitting we used experimental samples with N composition in the range of 0-0.06, In composition from 0 to 0.17, and Sb composition in the range of 0-0.08. All samples were thermally annealed to minimize the band gap shift caused by the short range ordering effects in GaInNAsSb crystal. The modified model yields an excellent fit to the experimental band gap data with an accuracy of ~20 meV, and is a practical tool for designing, fabricating and analyzing optoelectronics devices.

  3. Carrier concentration dependence of donor activation energy in n-type GaN epilayers grown on Si (1 1 1) by plasma-assisted MBE

    SciTech Connect

    Kumar, Mahesh; Bhat, Thirumaleshwara N.; Roul, Basanta; Rajpalke, Mohana K.; Kalghatgi, A.T.; Krupanidhi, S.B.

    2012-06-15

    Highlights: ► The n-type GaN layers were grown by plasma-assisted molecular beam epitaxy. ► The optical characteristics of a donor level in Si-doped GaN were studied. ► Activation energy of a Si-related donor was estimated from temperature dependent PL measurements. ► PL peak positions, FWHM of PL and activation energies are found to be proportional to the cube root of carrier density. ► The involvement of donor levels is supported by the temperature-dependent electron concentration measurements. -- Abstract: The n-type GaN layers were grown by plasma-assisted MBE and either intentionally doped with Si or unintentionally doped. The optical characteristics of a donor level in Si-doped, GaN were studied in terms of photoluminescence (PL) spectroscopy as a function of electron concentration. Temperature dependent PL measurements allowed us to estimate the activation energy of a Si-related donor from temperature-induced decay of PL intensity. PL peak positions, full width at half maximum of PL and activation energies are found to be proportional to the cube root of carrier density. The involvement of donor levels is supported by the temperature-dependent electron concentration measurements.

  4. Arsenic-induced intensity oscillations in reflection high-energy electron diffraction measurements. [during MBE of GaAs and InAs

    NASA Technical Reports Server (NTRS)

    Lewis, B. F.; Fernandez, R.; Grunthaner, F. J.; Madhukar, A.

    1986-01-01

    A technique of arsenic-induced RHEED intensity oscillations has been used to accurately measure arsenic incorporation rates as a function of substrate temperature during the homoepitaxial growths of both GaAs and InAs by molecular beam epitaxy (MBE). Measurements were made at growth temperatures from 350 to 650 C and at arsenic fluxes of 0.1 to 10.0 monolayer/s. The method measures only the arsenic actually incorporated into the growing film and does not include the arsenic lost in splitting the arsenic tetramers or lost by evaporation from the sample.

  5. Pulser development for MBE-4

    SciTech Connect

    Gough, D.E.; Brodzik, D.A.

    1986-06-01

    The Multiple Beam Experiment MBE4 is designed to accelerate four cesium ion beams from 200 kV to about 1 MV using an induction linac and to demonstrate the process of current amplification simultaneously with acceleration. The injected beam is obtained from a source using a Marx generator providing typically 10 mA/beam with a length of 1.6 meters. This is equivalent to a beam duration time of about 3 ..mu..sec. Twenty four acceleration gaps in groups of four are distributed along the length of the machine which will be some 16 meters long when completed. Each group of four acceleration gaps with appropriate quadrupoles form one section of the machine, identified as A through F. Careful tailoring of the acceleration voltage waveforms at each gap is required to accelerate the beam, amplify the current and provide longitudinal focusing. Ideal voltage waveforms for each gap were generated for a gap voltage limit initially set at 30 kV. These waveforms are shown in Fig. 1. The waveforms for the first 4 gaps are triangular with an approximate width of 3 ..mu..sec, becoming flatter and shorter at subsequent gaps as the beam bunch velocity increases. Ninety two nickel-iron tape wound cores capable of 6.8 mVsec/core and twenty six silicon steel tape wound cores capable of 24 mVsec/core were available. Groups of cores at the first eight gaps have been used in conjunction with an appropriate number of pulsers to provide the necessary accelerating voltage waveforms together with the pulser waveforms at every fourth acceleration gap which provides the longitudinal focusing of the beam. This paper will deal with the performance of the pulsers for the first eight gaps of acceleration and expectations for the next four, currently under construction.

  6. Evidence for void formation in MBE-grown silicon

    SciTech Connect

    Simpson, P.J.; Schultz, P.J. . Dept. of Physics Ontario Centre for Materials Research, Kingston, ON ); Jackman, T.E.; Aers, G.C.; Noeel, J.; Houghton, D.C. ); Perovic, D.D.; Weatherly, G.C. )

    1991-02-01

    In this paper, the authors give evidence for reproducible formation of voids of 3 to 6 nm diameter in (100) silicon epilayers, which were grown using molecular beam epitaxy (MBE) method in a narrow temperature range below 260 {degree}C. The results are given of an experimental investigation using variable-energy positrons and transmission electron microscopy (TEM). The expression used for the positron range, derived from work done below 10 keV, appears to be inaccurate when extrapolated to higher energy. (AIP)

  7. van der Waals Heterostructures Grown by MBE

    NASA Astrophysics Data System (ADS)

    Hinkle, Christopher

    In this work, we demonstrate the high-quality MBE heterostructure growth of various layered 2D materials by van der Waals epitaxy (VDWE). The coupling of different types of van der Waals materials including transition metal dichalcogenide thin films (e.g., WSe2, WTe2, HfSe2) , insulating hexagonal boron nitride (h-BN), and topological insulators (e.g., Bi2Se3) allows for the fabrication of novel electronic devices that take advantage of unique quantum confinement and spin-based characteristics. The relaxed lattice-matching criteria of van der Waals epitaxy has allowed for high-quality heterostructure growth with atomically abrupt interfaces, allowing us to couple these materials based primarily on their band alignment and electronic properties. We will discuss the impact of sample preparation, surface reactivity, and lattice mismatch of various substrates (sapphire, graphene, TMDs, Bi2Se3) on the growth mode and quality of the films and will discuss our studies of substrate temperature and flux rates on the resultant growth and grain size. Structural and chemical characterization was conducted via reflection high energy electron diffraction (RHEED, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning tunneling microscopy/spectroscopy (STM/S), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Experimentally determined band alignments have been determined and compared with first-principles calculations allowing the design of novel low-power logic and magnetic memory devices. Initial results from the electrical characterization of these grown thin films and some simple devices will also be presented. These VDWE grown layered 2D materials show significant potential for fabricating novel heterostructures with tunable band alignments and magnetic properties for a variety of nanoelectronic and optoelectronic applications.

  8. MBE HgCdTe heterostructure detectors

    NASA Technical Reports Server (NTRS)

    Schulman, Joel N.; Wu, Owen K.

    1990-01-01

    HgCdTe has been the mainstay for medium (3 to 5 micron) and long (10 to 14 micron) wavelength infrared detectors in recent years. Conventional growth and processing techniques are continuing to improve the material. However, the additional ability to tailor composition and placement of doped layers on the tens of angstroms scale using molecular beam epitaxy (MBE) provides the opportunity for new device physics and concepts to be utilized. MBE-based device structures to be discussed here can be grouped into two categories: tailored conventional structures and quantum structures. The tailored conventional structures are improvements on familiar devices, but make use of the ability to create layers of varying composition, and thus band gap, at will. The heterostructure junction can be positioned independently of doping p-n junctions. This allows the small band gap region in which the absorption occurs to be separated from a larger band gap region in which the electric field is large and where unwanted tunneling can occur. Data from hybrid MBE/liquid phase epitaxy (LPE)/bulk structures are given. Quantum structures include the HgTe-CdTe superlattice, in which the band gap and transport can be controlled by alternating thin layers (tens of angstroms thick) of HgTe and CdTe. The superlattice has been shown to exhibit behavior which is non-alloy like, including very high hole mobilities, two-dimensional structure in the absorption coefficient, resonant tunneling, and anisotropic transport.

  9. Defect energy levels in p-type GaAsBi and GaAs grown by MBE at low temperatures

    NASA Astrophysics Data System (ADS)

    Mooney, P. M.; Tarun, M. C.; Bahrami-Yekta, V.; Tiedje, T.; Lewis, R. B.; Masnadi-Shirazi, M.

    2016-06-01

    Deep level defects in p-type GaAs1‑x Bi x (x < 1%) and GaAs grown by molecular beam epitaxy at substrate temperatures of 330 °C and 370 °C have been characterized by deep level transient spectroscopy. We find that incorporating Bi into GaAs at 330 °C does not affect the total concentration of hole traps, which is ∼4 × 1016 cm‑3, comparable to the concentration of electron traps observed in Si-doped GaAsBi having a similar alloy composition. Increasing the growth temperature of the p-type GaAsBi (x = 0.8%) layer from 330 °C to 370 °C reduces the hole trap concentration by an order of magnitude. Moreover, the defects having near mid-gap energy levels that are the most efficient non-radiative recombination centers are present only in GaAsBi layers grown at the lower temperature. These new results are discussed in the context of previous measurements of n-type GaAs and GaAsBi layers grown under similar conditions.

  10. MBE grown high quality GaN films and devices

    NASA Astrophysics Data System (ADS)

    Kim, W.; Aktas, O.; Salvador, A.; Botchkarev, A.; Sverdlov, B.; Mohammad, S. N.; Morkoç, H.

    1997-02-01

    GaN films with much improved structural, transport, and optical properties have been prepared by molecular beam epitaxy using NH 3 as a nitrogen source. Films with a wide range of resistivity, including highly resistive ones, were grown with a chosen growth rate of 1.2 μm/h. The electron mobility in modulation doped structures is about 450 and 850 cm 2/Vs at 300 and 77 K, respectively, with an areal carrier concentration of about 10 13 cm -2. Low temperature luminescence shows A- and B-free-excitons as well as the excited state of the A- and B-excitons, the first known observation, attesting to the quality of the samples. These transition energies are consistent with the best MOCVD samples and represent a sizable reduction of the pandemic zincblende phase in MBE grown films. The high quality of films was demonstrated by the realization of high performance MODFETs and Schottky diodes.

  11. Characterization of MBE-grown Semiconductor Materials for Photovoltaic Applications

    NASA Astrophysics Data System (ADS)

    Tang, Dinghao

    The research described in this dissertation involved the use of transmission electron microscopy (TEM) to characterize II-VI and III-V compound semiconductor quantum dots (QDs) and dilute-nitride alloys grown by molecular beam epitaxy (MBE) and intended for photovoltaic applications. The morphology of CdTe QDs prepared by the post-annealing MBE method were characterized by various microscopy techniques including high-resolution transmission electron microscopy (HR-TEM), and high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM). Extensive observations revealed that the of QD shapes were not well-defined, and the QD size and spatial distribution were not determined by the amount of CdTe deposition. These results indicated that the formation of II-VI QDs using a post-annealing treatment did not follow the conventional growth mechanism for III-V and IV-IV materials. The structural properties of dilute-nitride GaAsNx films grown using plasma-assisted MBE were characterized by TEM and HAADF-STEM. A significant amount of the nitrogen incorporated into the dilute nitride films was found to be interstitial, and that fluctuations in local nitrogen composition also occurred during growth. Post-growth partial relaxation of strain resulted in the formation of {110}-oriented microcracks in the sample with the largest substitutional nitrogen composition. Single- and multi-layered InAs QDs grown on GaAsSb/GaAs composite substrates were investigated using HR-TEM and HAADF-STEM. Correlation between the structural and optoelectronic properties revealed that the GaAsSb barrier layers had played an important role in tuning the energy-band alignments but without affecting the overall structural morphology. However, according to both XRD measurement and electron microscopy the densities of dislocations increased as the number of QD layers built up. An investigation of near-wetting layer-free InAs QDs incorporated with AlAs/GaAs spacer layers was carried out

  12. 50. VIEW TO EAST; SOUTH END OF MBE BUILDING, FIRST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. VIEW TO EAST; SOUTH END OF MBE BUILDING, FIRST FLOOR; SAFE, DOOR OPEN ELECTRONIC FLASH INTERIOR ILLUMINATION (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  13. 15. VIEW TO SOUTHWEST; EAST BACK MBE BUILDING, THIRD AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW TO SOUTHWEST; EAST BACK MBE BUILDING, THIRD AND SECOND FLOORS; GASOLINE PUMPS CENTER (Dobson) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  14. 51. VIEW TO SOUTHWEST; SOUTH END OF MBE BUILDING, SECOND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. VIEW TO SOUTHWEST; SOUTH END OF MBE BUILDING, SECOND FLOOR; MAIN ENTRANCE TO FORMER REGIONAL OFFICES OF REA (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  15. 39. VIEW TO NORTHEAST; WEST FRONT MBE BUILDING, FIRST FLOOR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. VIEW TO NORTHEAST; WEST FRONT MBE BUILDING, FIRST FLOOR, FRED HARVEY NEWSSTAND STOREROOM (AREA BURNED BY VANDALS) (Dobson) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  16. 54. VIEW TO SOUTH; SOUTH END OF MBE BUILDING, THIRD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    54. VIEW TO SOUTH; SOUTH END OF MBE BUILDING, THIRD FLOOR, HALLWAY AND DOOR TO FORMER REGIONAL OFFICES OF REA (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  17. 40 CFR 33.209 - Can EPA re-evaluate the MBE or WBE status of an entity after EPA certifies it to be an MBE or WBE?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Can EPA re-evaluate the MBE or WBE status of an entity after EPA certifies it to be an MBE or WBE? 33.209 Section 33.209 Protection of... EPA re-evaluate the MBE or WBE status of an entity after EPA certifies it to be an MBE or WBE? (a)...

  18. MBE growth and magneto-optic properties of magnetic multilayers

    NASA Astrophysics Data System (ADS)

    Falco, Charles M.; Engel, Brad N.

    Recent interest in the magnetic and magneto-optic properties of transition metal/transition metal multilayers has been stimulated by the discovery of perpendicular magnetism in particular systems such as Co/Pd and Co/Pt. Due to their favorable magneto-optic wavelength dependence and enhanced corrosion resistance, these materials show promise as future data storage media. However, partially due to the large variety of thin-film deposition methods and growth conditions, it has been difficult to obtain a clear understanding of the mechanisms of magnetic anisotropy in these systems. In order to create controlled and well characterized model systems, we have grown a series of epitaxial Co/Pd superlattices oriented along the three high-symmetry crystal directions [001], [110], and [111] on single-crystal GaAs substrates by molecular beam epitaxy [MBE]. Simultaneously, we have deposited polycrystalline Co/Pd multilayers on Si substrates mounted alongside the GaAs for direct comparisons of epitaxial and non-epitaxial films produced under identical conditions. The structural properties of these multilayers were determined by low-and reflection high-energy electron diffraction (LEED and RHEED), low- and high-angle X-ray diffraction, and scanning tunneling microscopy (STM). The dependence of the uniaxial magnetic anisotropy energy on the Co thickness in these superlattices showed significant systematic differences for each of the three crystal orientations. A review of our work on the structural influences responsible for these differences is presented.

  19. 40 CFR 33.503 - How does a recipient calculate MBE and WBE participation for reporting purposes?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... attributable to the MBE or WBE. If an MBE's or WBE's risk of loss, control or management responsibilities is... performing a commercially useful function: (1) The MBE or WBE must be responsible for the management...

  20. 40 CFR 33.503 - How does a recipient calculate MBE and WBE participation for reporting purposes?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... attributable to the MBE or WBE. If an MBE's or WBE's risk of loss, control or management responsibilities is... performing a commercially useful function: (1) The MBE or WBE must be responsible for the management...

  1. 40 CFR 33.503 - How does a recipient calculate MBE and WBE participation for reporting purposes?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... attributable to the MBE or WBE. If an MBE's or WBE's risk of loss, control or management responsibilities is... performing a commercially useful function: (1) The MBE or WBE must be responsible for the management...

  2. 40 CFR 33.503 - How does a recipient calculate MBE and WBE participation for reporting purposes?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... attributable to the MBE or WBE. If an MBE's or WBE's risk of loss, control or management responsibilities is... performing a commercially useful function: (1) The MBE or WBE must be responsible for the management...

  3. Let the Questions Be Your Guide: MBE as Interdisciplinary Science

    ERIC Educational Resources Information Center

    Rose, L. Todd; Daley, Samantha G.; Rose, David H.

    2011-01-01

    From its inception, the field of Mind, Brain, and Education (MBE) has been conceived as an interdisciplinary science, and with good reason: The phenomena the field aims to understand often arise from interactions among multiple factors, span levels of analysis, and are context dependent. In this article, we argue that to reach its potential as an…

  4. 47. VIEW TO WEST; SOUTH END OF MBE BUILDING, FIRST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    47. VIEW TO WEST; SOUTH END OF MBE BUILDING, FIRST FLOOR; FORMER PACKAGE HANDLING AREA ADJACENT TO FORMER PACIFIC ELECTRIC RAILWAY TERMINAL (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  5. 52. VIEW TO EAST; SOUTH END OF MBE BUILDING, SECOND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. VIEW TO EAST; SOUTH END OF MBE BUILDING, SECOND FLOOR; HIGHLY ALTERED INTERIOR OFFICE SPACE, FORMERLY REGIONAL OFFICES OF REA (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  6. 53. VIEW TO SOUTHEAST; SOUTH END OF MBE BUILDING, SECOND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. VIEW TO SOUTHEAST; SOUTH END OF MBE BUILDING, SECOND FLOOR; HIGHLY ALTERED INTERIOR OFFICE SPACE, FORMERLY REGIONAL OFFICES OF REA (Andersen) - Los Angeles Union Passenger Terminal, Mail, Baggage, & Express Building, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  7. Multiband spectral emitters matched to MBE grown photovoltaic cells

    SciTech Connect

    Wong, E.M.; Hickey, J.P.; Holmquist, G.A.; Uppal, P.N.; Waldman, C.H.

    1996-02-01

    Clearly TPV devices are of considerable interest for power generation. For practical devices it is desirable to have high efficiencies combined with low temperature operation. Photovoltaic cells which can convert the energy at the longer wavelengths of interest are needed to complete such a system. The spectral emission peak of Yb{sub 2}O{sub 3} is well matched to the band gap of Si; however, the longer wavelength, spectral emissions of other rare earth oxides can also be exploited through the use of III{endash}V semiconductor compounds such as GaSb or alloys of GaInAsSb. By doping GaSb with InAs, the band gap of the resulting material can be effectively varied depending upon the concentration of InAs in the quaternary alloy. The ability to tailor the emitter materials and, in conjunction, the photovoltaic materials leads to greater efficiencies through spectral matching. Two binary rare earth oxide combinations, Er{sub 2}O{sub 3}/Ho{sub 2}O{sub 3} and Er{sub 2}O{sub 3}/Yb{sub 2}O{sub 3}, were studied. The mixtures were found to give multiple peak spectral emission in the wavelengths of interest. The intensity of the peaks were compositionally dependent though it did not vary in a linear fashion. Photon efficiencies of the molecular beam epitaxially (MBE) grown GaSb cell and GaInAsSb quaternary cell were measured when used in conjunction with the Er{sub 2}O{sub 3}/Ho{sub 2}O{sub 3} emitters in which the concentration of Er{sub 2}O{sub 3} and Ho{sub 2}O{sub 3} were varied. The results demonstrated promise for further work. {copyright} {ital 1996 American Institute of Physics.}

  8. Effects of incident short wavelength (UV) light on the morphology of MBE grown GaAs

    NASA Astrophysics Data System (ADS)

    Beaton, Daniel A.; Sanders, Charlotte; Alberi, Kirstin

    2014-03-01

    The exploration of novel semiconductor materials increasingly relies on growth techniques that operate far from equilibrium in order to overcome thermodynamic limitations to synthesis. As one example, low temperature molecular beam epitaxy (MBE) offers a pathway to enhance substitutional dopant incorporation over surface segregation but adatom mobility suffers as a consequence and leads to higher concentrations of lattice defects. We explore the use of external stimuli, namely incident UV light, as a means to influence adatom kinetics; UV light is absorbed in the first few atomic layers of the as-growing epitaxial film and the effects of the incident radiation predominantly effect only the surface adatoms. GaAs homoepitaxy by MBE is studied as a model case as a function of illumination conditions under broadband Xe and KrF excimer laser irradiation. In-situ reflective high energy electron diffraction analysis paired with ex-situ atomic force microscopy measurements yields insight into the effects of photon irradiation on surface adatom mobility, morphology and smoothing processes. This work was supported by the DOE Office of Science, Basic Energy Sciences under contract DE-AC36-08GO28308.

  9. Cross-Sectional Study of Macrodefects in MBE Dual-Band HgCdTe on CdZnTe

    NASA Astrophysics Data System (ADS)

    Reddy, M.; Lofgreen, D. D.; Jones, K. A.; Peterson, J. M.; Radford, W. A.; Benson, J. D.; Johnson, S. M.

    2013-11-01

    HgCdTe dual-band mid-wave infrared/long-wave infrared focal-plane arrays on CdZnTe are a key component in advanced electrooptic sensor applications. Molecular beam epitaxy (MBE) has been used successfully for growth of dual-band layers on larger CdZnTe substrates. However, the macrodefect density, which is known to reduce the pixel operability and its run-to-run variation, is larger when compared with layers grown on Si substrate. This paper reports the macrodefect density versus size signature of a well-optimized MBE dual-band growth and a cross-sectional study of a macrodefect that represents the most prevalent class using focused ion beam, scanning transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The results show that the macrodefect originates from a void, which in turn is associated with a pit on the CdZnTe substrate.

  10. MBE of wide bandgap II-VI compounds

    NASA Astrophysics Data System (ADS)

    Gunshor, R. L.; Kobayashi, M.; Kolodziejski, L. A.; Otsuka, N.; Nurmikko, A. V.

    1990-01-01

    A pseudomorphic epilayer/epilayer heterojunction consisting of ZnTe on AlSb, having potential for the development of novel visible light emitting injection devices, has been grown by MBE. A variety of microstructural and optical evaluation techniques have provided evidence of high structural quality. The nonequilibrium growth capability of the MBE technique has enabled the growth of heterostructures incorporating a previously hypothetical widegap magnetic semiconductor, the zincblende phase of MnTe. Electron diffraction measurements of cross-sectional samples reveal only zincblende phases. Double barrier structures incorporating zincblende MnTe are found to exhibit two-dimensional electron and hole confinement in CdTe and ZnTe quantum well layers, and serve to confirm the zincblende MnTe bandgap at 3.2 eV.

  11. Unraveling the electron pairing mechanism of FeSe by MBE and STM

    NASA Astrophysics Data System (ADS)

    Song, Canli

    Studies of high-transition-temperature superconductivity usually suffer from various imperfections in materials. Here we apply the state-of-the-art molecular beam epitaxy (MBE) to prepare controllably high-quality FeSe films on various substrates, and explore their superconducting properties using cryogenic scanning tunneling microscope. Single impurities, twin boundaries as well as strain are found in the MBE-grown FeSe films on graphene, and invariably suppress the superconductivity. Meanwhile, electronic nematicity and signatures of a bosonic mode, whose energy also decreases with strain, were identified. More significantly, we observed two disconnected superconducting domes at alkali-metal potassium (K)-dosed FeSe surface, stepping towards the mechanistic understanding of superconductivity in FeSe-derived superconductors. Our results are clarifying the secret of high-Tc superconductivity in FeSe-related superconductors, and by implications, in other unconventional superconductors, and guiding how to enhance Tc by interface engineering. This work was nancially supported by National Science Foundation and Ministry of Science and Technology of China.

  12. Preface of the 18th International Conference on Molecular Beam Epitaxy (MBE 2014)

    NASA Astrophysics Data System (ADS)

    Brown, April S.; Ptak, Aaron J.

    2015-09-01

    The first International Conference on Molecular Beam Epitaxy (IC-MBE) was held in Paris in 1978, chaired by Alfred Y. Cho. Every other year since, with the exception of a four-year break after the initial meeting, the IC-MBE has been held in European, Asian, and North American venues. The 18th and latest IC-MBE was held in Flagstaff, Arizona, USA, September 7-12, 2014, and was chaired by Yong-Hang Zhang (Arizona State University). MBE is an advanced crystal growth method that benefits areas from the study of fundamental physics, all the way through the production of devices used in countless fields. IC-MBE brings together researchers from all over the world, and is the premier forum for scientific and technological exchange among researchers investigating all types of materials growth using the MBE technique.

  13. Superlattice structures grown by metalorganic MBE

    NASA Astrophysics Data System (ADS)

    Tokumitsu, E.; Katoh, T.; Sung, C. P.; Sandhu, A.; Kimura, R.; Konagai, M.; Takahashi, K.

    1986-08-01

    The metalorganic molecular beam epitaxial (MOMBE) growth of GaAs and (GaAl)As using triethylgallium (TEG) and triethylaluminum (TEA) has been studied. GaAs/GaAlAs multi quantum well (MQW) heterostructures were fabricated and it was found that the photoluminescence peak energy at room temperature agreed with calculated values. Furthermore, a new technique to grow a nipi superlattice structure was proposed and as a trial growth a n-GaAs/n +-GaAs multilayer was prepared by applying an alternating ionization voltage to hydrogen.

  14. Incorporation and desorption of sulphur In InP grown by MBE

    NASA Astrophysics Data System (ADS)

    Airaksinen, V. M.; Cheng, T. S.; Stanley, C. R.

    1987-02-01

    Sulphur doped InP has been grown by molecular beam epitaxy (MBE) using an electrochemical cell as a source of sulphur dimer S 2. At growth temperatures of over 500°C sulphur is lost from the layers as a volatile indium sulphide which desorbs with an activation energy of 4.5 eV. The concentration of incorporated sulphur ( C S) is linearly proportional to the incident sulphur flux both at low ( T s < 500°C) and high ( T s > 500°C) growth temperatures, indicating first order kinetics of incorporation and desorption f sulphur. The desorption cannot be suppressed by increasing the P 2: In flux ratio. The desorption rate is also independent of the incident indium flux. A thermodynamic analysis shows that the most likely desorbing species is In 2S.

  15. 40 CFR 33.211 - What is the process for appealing or challenging an EPA MBE or WBE certification determination?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... challenging an EPA MBE or WBE certification determination? 33.211 Section 33.211 Protection of Environment... process for appealing or challenging an EPA MBE or WBE certification determination? (a) An entity which has been denied MBE or WBE certification by EPA OSDBU under § 33.205 or § 33.209 may appeal...

  16. 40 CFR 33.407 - How long do MBE and WBE fair share objectives remain in effect?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false How long do MBE and WBE fair share... ENVIRONMENTAL PROTECTION AGENCY PROGRAMS Fair Share Objectives § 33.407 How long do MBE and WBE fair share objectives remain in effect? Once MBE and WBE fair share objectives have been negotiated, they will remain...

  17. Transverse combining of 4 beams in MBE-4

    SciTech Connect

    Celata, C.M.; Chupp, W.; Faltens, A.; Fawley, W.M.; Ghiorso, W.; Hahn, K.D.; Henestroza, E.; Peters, C.; Seidl, P.

    1995-05-01

    Transverse beam combining is a cost-saving optio employed in many designs for induction linac heavy ion fusion drivers. But resultant transverse emittance increase, due predominantly to anharmonic space charoe forces, must be kept minimal so as not to sacrifice focusability at the target. A prototype combining experiment has been built, using the MBE-4 experiment. Four sources produce four 4 mA Cs{sup +} beams at 200 keV. The ion sources are angled toward each other, so that beams converge. Focusing upstream of the merge consists of 4 quadrupoles and a final combined-function element (quadrupole & dipole). All lattice elements are electrostatic. Due to the small distance between beams at the last element ({approximately} 2 mm), the electrodes here are a cage of small wires, each at different voltage. The beams emerge into the 30 period transport lattice of MBE-4 where emittance growth due to merging, as well as the subsequent evolution of the distribution function, can be diagnosed. The combiner design, simulation predictions, and preliminary results from the experiment are presented.

  18. Molecular Beam Epitaxial (MBE) Growth and Characterization of Thin Films of Semiconductor Tin

    NASA Astrophysics Data System (ADS)

    Folkes, P.; Taylor, P.; Rong, C.; Nichols, B.; Hier, H.; Burke, R.; Neupane, M.

    Recent theoretical predictions that a two-dimensional monolayer of semiconductor tin is a two-dimensional topological insulator and experimental evidence of three-dimensional topological insulator behavior in strained ultrathin films of semiconductor tin grown by MBE on InSb has generated intense research interest. This research is primarily focused on the MBE growth and topological characteristics of ultrathin films of semiconductor tin. In this talk we present results of a study on the MBE growth and the transport, structural and optical characterization of thin films of semiconductor tin on several different substrates.

  19. MBE-4, a heavy ion multiple-beam experiment

    SciTech Connect

    Avery, R.T.; Chavis, C.S.; Fessenden, T.J.; Gough, D.E.; Henderson, T.F.; Keefe, D.; Meneghetti, J.R.; Pike, C.D.; Vanecek, D.L.; Warwick, A.I.

    1985-05-01

    MBE-4, a heavy-ion multiple beam induction linac being built at LBL in FY85/86, will model many features of a much longer device. It will accelerate four space-charge-dominated cesium ion beams from, for example, 0.2 MeV, 5 mA/beam, 3.0 ..mu..sec, 1.6 m length at injection to approx.0.8 MeV, 15 mA/beam, 1.0 ..mu..sec, 1.1 m length at the exit. It will permit study of simultaneous focussing, acceleration, current amplification and emittance growth of multiple space-charge-dominated ion beams. Some features of this accelerator are described. 11 refs., 5 figs.

  20. Investigation of Substrate Effects on Interface Strain and Defect Generation in MBE-Grown HgCdTe

    NASA Astrophysics Data System (ADS)

    Gu, R.; Lei, W.; Antoszewski, J.; Faraone, L.

    2016-09-01

    Si, Ge, and GaAs have been extensively investigated as alternative substrates for molecular-beam epitaxy (MBE) growth of HgCdTe and, at present, are widely used for HgCdTe-based infrared focal-plane arrays. However, the problem of high dislocation density in HgCdTe layers grown on these lattice-mismatched substrates has yet to be resolved. In this work, we investigated another alternative substrate, GaSb, which has a significantly smaller lattice mismatch with HgCdTe in comparison with Si, Ge, and GaAs, and is readily available as large-area, epiready wafers at much lower cost in comparison with lattice-matched CdZnTe substrates. The resultant stress due to lattice and thermal mismatch between the HgCdTe epilayer and various substrates has been calculated in this work using the elasticity matrix, and the corresponding stress distribution simulated using ANSYS. The simulated structures were matched by experimental samples involving MBE growth of HgCdTe on GaAs, GaSb, and CdZnTe substrates, and were characterized via reflection high-energy electron diffraction and x-ray diffraction analysis, followed by etch pit density (EPD) analysis. In comparison with other alternative substrates, GaSb is shown to have lower interface stress and lower EPD, rendering it an interesting and promising alternative substrate material for HgCdTe epitaxy.

  1. Investigation of Substrate Effects on Interface Strain and Defect Generation in MBE-Grown HgCdTe

    NASA Astrophysics Data System (ADS)

    Gu, R.; Lei, W.; Antoszewski, J.; Faraone, L.

    2016-05-01

    Si, Ge, and GaAs have been extensively investigated as alternative substrates for molecular-beam epitaxy (MBE) growth of HgCdTe and, at present, are widely used for HgCdTe-based infrared focal-plane arrays. However, the problem of high dislocation density in HgCdTe layers grown on these lattice-mismatched substrates has yet to be resolved. In this work, we investigated another alternative substrate, GaSb, which has a significantly smaller lattice mismatch with HgCdTe in comparison with Si, Ge, and GaAs, and is readily available as large-area, epiready wafers at much lower cost in comparison with lattice-matched CdZnTe substrates. The resultant stress due to lattice and thermal mismatch between the HgCdTe epilayer and various substrates has been calculated in this work using the elasticity matrix, and the corresponding stress distribution simulated using ANSYS. The simulated structures were matched by experimental samples involving MBE growth of HgCdTe on GaAs, GaSb, and CdZnTe substrates, and were characterized via reflection high-energy electron diffraction and x-ray diffraction analysis, followed by etch pit density (EPD) analysis. In comparison with other alternative substrates, GaSb is shown to have lower interface stress and lower EPD, rendering it an interesting and promising alternative substrate material for HgCdTe epitaxy.

  2. MBE-Grown CdTe Layers on GaAs with In-assisted Thermal Deoxidation

    NASA Astrophysics Data System (ADS)

    Arı, Ozan; Bilgilisoy, Elif; Ozceri, Elif; Selamet, Yusuf

    2016-03-01

    Molecular beam epitaxy (MBE) growth of thin (˜2 μm) CdTe layers characterized by high crystal quality and low defect density on lattice mismatched substrates, such as GaAs and Si, has thus far been difficult to achieve. In this work, we report the effects of in situ thermal deoxidation under In and As4 overpressure prior to the CdTe growth on epiready GaAs(211)B wafers, aiming to enhance CdTe crystal quality. Thermally deoxidized GaAs samples were analyzed using in situ reflection high energy electron diffraction, along with ex situ x-ray photo-electron spectroscopy (XPS) and atomic force microscopy. MBE-grown CdTe layers were characterized using x-ray diffraction (XRD) and Everson-type wet chemical defect decoration etching. We found that In-assisted desorption allowed for easier surface preparation and resulted in a smoother surface compared to As-assisted surface preparation. By applying In-assisted thermal deoxidation to GaAs substrates prior to the CdTe growth, we have obtained single crystal CdTe films with a CdTe(422) XRD rocking curve with a full-width half-maximum value of 130.8 arc-s and etch pit density of 4 × 106 cm-2 for 2.54 μm thickness. We confirmed, by XPS analysis, no In contamination on the thermally deoxidized surface.

  3. 40 CFR 33.209 - Can EPA re-evaluate the MBE or WBE status of an entity after EPA certifies it to be an MBE or WBE?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Can EPA re-evaluate the MBE or WBE... Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE PARTICIPATION BY DISADVANTAGED BUSINESS ENTERPRISES IN UNITED STATES ENVIRONMENTAL PROTECTION AGENCY PROGRAMS Certification § 33.209...

  4. MBE growth of topological insulator Bi2Se3 and Bi2Te3 films

    NASA Astrophysics Data System (ADS)

    Zhang, Tong; Levy, Niv; Song, Young Jae; Chae, Jungseok; Stroscio, Joseph A.

    2011-03-01

    Three-dimensional (3D) topological insulators are a new state of quantum matter with a band gap in bulk but gapless states on the surface. The surface states with spin helicity can be the host of many striking quantum phenomena. In this work, we use ultrahigh vacuum molecular beam epitaxy to grow atomically flat topological insulator (TI) Bi2Se3 and Bi2Te3 films. High quality TI films were obtained using epitaxial graphene on SiC as a substrate for TI growth. The growth dynamics was characterized by real time reflection high-energy electron diffraction (RHEED). The growth condition was optimized by adjusting for proper flux rate and substrate temperature while monitoring the RHEED patterns. In situ Auger spectroscopy and scanning tunneling microscopy (STM) measurements at 5K are used to study the as-grown films for their stoichiometry and defect density. We expect these MBE grown samples will provide a good candidate for studying the topological surface states and related phenomena, which will be studied using scanning tunneling spectroscopy at millikelvin temperatures

  5. IMPORTANCE OF IN SITU MONITORS IN THE PREPARATION OF LAYERED OXIDE HETEROSTRUCTURES BY REACTIVE MBE.

    SciTech Connect

    Schlom, Darrell G.; Haeni, J. H.; Theis, C. D.; Tian, W.; Pan, X. Q.; Brown, G. W.; Hawley, M. E.

    2001-01-01

    Using a variety of in situ monitors and when possible adsorption-controlled growth conditions, layered oxide heterostructures including new compounds and metastable superlattices have been grown by reactive molecular beam epitaxy (MBE). The heteroepitaxial layers grown include Bi{sub 4}Ti{sub 3}O{sub 12}-SrTiO{sub 3} and Bi{sub 4}Ti{sub 3}O{sub 12}-PbTiO{sub 3} Aurivillius phases, Sr{sub n+1}Ti{sub n}O{sub 3n+1} Ruddlesden-Popper phases, and metastable PbTiO{sub 3}/SrTiO{sub 3} and BaTiO{sub 3}/SrTiO{sub 3} superlattices. Accurate composition control is key to the controlled growth of such structures, and to this end combinations of reflection high-energy electron diffraction (RHEED), atomic absorption spectroscopy (AA), a quartz crystal microbalance (QCM), and adsorption-controlled growth conditions were employed during growth. The structural perfection of the films has been investigated using in situ RHEED, four-circle x-ray diffraction, atomic force microscopy (AFM), and high-resolution transmission electron microscopy (TEM).

  6. Characterization of MBE-grown InAlN/GaN heterostructure valence band offsets with varying In composition

    NASA Astrophysics Data System (ADS)

    Jiao, Wenyuan; Kong, Wei; Li, Jincheng; Collar, Kristen; Kim, Tong-Ho; Losurdo, Maria; Brown, April S.

    2016-03-01

    Angle-resolved X-ray photoelectron spectroscopy (XPS) is used in this work to experimentally determine the valence band offsets of molecular beam epitaxy (MBE)-grown InAlN/GaN heterostructures with varying indium composition. We find that the internal electric field resulting from polarization must be taken into account when analyzing the XPS data. Valence band offsets of 0.12 eV for In0.18Al0.82N, 0.15 eV for In0.17Al0.83N, and 0.23 eV for In0.098Al0.902N with GaN are obtained. The results show that a compositional-depended bowing parameter is needed in order to estimate the valence band energies of InAlN as a function of composition in relation to those of the binary endpoints, AlN and InN.

  7. 40 CFR 33.503 - How does a recipient calculate MBE and WBE participation for reporting purposes?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... attributable to the MBE or WBE. If an MBE's or WBE's risk of loss, control or management responsibilities is... ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE PARTICIPATION BY DISADVANTAGED BUSINESS... consistent with normal business practices. (1) Presumption. If 50% or more of the total dollar amount of...

  8. 40 CFR 33.208 - How long does an MBE or WBE certification from EPA last?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false How long does an MBE or WBE certification from EPA last? 33.208 Section 33.208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE PARTICIPATION BY DISADVANTAGED BUSINESS ENTERPRISES IN UNITED...

  9. 40 CFR 33.207 - Can an entity reapply to EPA for MBE or WBE certification?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Can an entity reapply to EPA for MBE or WBE certification? 33.207 Section 33.207 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE PARTICIPATION BY DISADVANTAGED BUSINESS ENTERPRISES IN UNITED...

  10. Influence of Growth Parameters and Annealing on Properties of MBE Grown GaAsSbN SQWs

    NASA Technical Reports Server (NTRS)

    Wu, Liangjin; Iyer, Shanthi; Nunna, Kalyan; Bharatan, Sudhakar; Li, Jia; Collis, Ward J.

    2005-01-01

    In this paper we report the growth of GaAsSbN/GaAs single quantum well (SQW) heterostructures by molecular beam epitaxy (MBE) and their properties. A systematic study has been carried out to determine the effect of growth conditions, such as the source shutter opening sequence and substrate temperature, on the structural and optical properties of the layers. The substrate temperatures in the range of 450-470 C were found to be optimal. Simultaneous opening of the source shutters (SS) resulted in N incorporation almost independent of substrate temperature and Sb incorporation higher at lower substrate temperatures. The effects of ex-situ annealing in nitrogen ambient and in-situ annealing under As ovepressure on the optical properties of the layers have also been investigated. A significant increase in photoluminescence (PL) intensity with reduced full width at half maxima (FWHM) in conjunction with a blue shift in the emission energy was observed on 10 annealing the samples. In in-situ annealed samples, the PL line shapes were more symmetric and the temperature dependence of the PL peak energy indicated significant decrease in the exciton localization energy as exhibited by a less pronounced S-shaped curve. The inverted S-shaped curve observed in the temperature dependence of PL FWHM is also discussed. 1.61 micrometer emission with FWHM of 25 meV at 20K has been obtained in in-situ annealed GaAsSbN/GaAs SQW grown at 470 C by SS.

  11. Performance of MBE-4: An experimental multiple beam induction linear accelerator for heavy ions

    SciTech Connect

    Warwick, A.I.; Fessenden, T.J.; Keefe, D.; Kim, C.H.; Meuth, H.

    1988-06-01

    An experimental induction linac, called MBE-4, has been constructed to demonstrate acceleration and current amplification of multiple heavy ion beams. This work is part of a program to study the use of such an accelerator as a driver for heavy ion inertial fusion. MBE-4 is 16m long and accelerates four space-charge-dominated beams of singly-charged cesium ions, in this case from 200 keV to 700 keV, amplifying the current in each beam from 10mA by a factor of nine. Construction of the experiment was completed late in 1987 and we present the results of detailed measurements of the longitudinal beam dynamics. Of particular interest is the contribution of acceleration errors to the growth of current fluctuations and to the longitudinal emittance. The effectiveness of the longitudinal focusing, accomplished by means of the controlled time dependence of the accelerating fields, is also discussed. 4 refs., 5 figs., 1 tab.

  12. Large format MBE HgCdTe on silicon detector development for astronomy

    NASA Astrophysics Data System (ADS)

    Hanold, Brandon J.; Figer, Donald F.; Lee, Joong; Kolb, Kimberly; Marcuson, Iain; Corrales, Elizabeth; Getty, Jonathan; Mears, Lynn

    2015-08-01

    The Center for Detectors at Rochester Institute of Technology and Raytheon Vision Systems (RVS) are leveraging RVS capabilities to produce large format, short-wave infrared HgCdTe focal plane arrays on silicon (Si) substrate wafers. Molecular beam epitaxial (MBE) grown HgCdTe on Si can reduce detector fabrication costs dramatically, while keeping performance competitive with HgCdTe grown on CdZnTe. Reduction in detector costs will alleviate a dominant expense for observational astrophysics telescopes. This paper presents the characterization of 2.5μm cutoff MBE HgCdTe/Si detectors including pre- and post-thinning performance. Detector characteristics presented include dark current, read noise, spectral response, persistence, linearity, crosstalk probability, and analysis of material defects.

  13. Growth of III-V films by control of MBE growth front stoichiometry

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

    1992-01-01

    For the growth of strain-layer materials and high quality single and multiple quantum wells, the instantaneous control of growth front stoichiometry is critical. The process of the invention adjusts the offset or phase of molecular beam epitaxy (MBE) control shutters to program the instantaneous arrival or flux rate of In and As4 reactants to grow InAs. The interrupted growth of first In, then As4, is also a key feature.

  14. Application of modern control theory to temperature control of the MBE system

    NASA Astrophysics Data System (ADS)

    Ishikawa, Takuya; Chan, Yuen Chuen; Nakano, Yoshiaki; Tada, Kunio

    1990-03-01

    The setup of an MBE control system without PID controllers, whereby one microprocessor manages all the Knudsen cells directly, is reported. The model-following algorithm is applied to the temperature control of the Knudsen cells, and improved dynamic response of the cell temperature is obtained compared with that obtained by the conventional PID algorithm. An application of the model-following algorithm to device fabrication is demonstrated.

  15. New MBE buffer for micron- and quarter-micron-gateGaAs MESFETs

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A new buffer layer has been developed that eliminates backgating in GaAs MESFETs and substantially reduces short-channel effects in GaAs MESFETs with 0.27-micron-long gates. The new buffer is grown by molecular beam epitaxy (MBE) at a substrate temperature of 200 C using Ga and As sub 4 beam fluxes. The buffer is crystalline, highly resistive, optically inactive, and can be overgrown with high quality GaAs. GaAs MESFETs with a gate length of 0.27 microns that incorporate the new buffer show improved dc and RF properties in comparison with a similar MESFET with a thin undoped GaAs buffer. To demonstrate the backgating performance improvement afforded by the new buffer, MESFETs were fabricated using a number of different buffer layers and structures. A schematic cross section of the MESFET structure used in this study is shown. The measured gate length, gate width, and source-drain spacing of this device are 2,98, and 5.5 microns, respectively. An ohmic contact, isolated from the MESFET by mesa etching, served as the sidegate. The MESFETs were fabricated in MBE n-GaAs layers grown on the new buffer and also in MBE n-GaAs layers grown on buffer layers of undoped GaAs, AlGaAs, and GaAs/AlGaAs superlattices. All the buffer layers were grown by MBE and are 2 microns thick. The active layer is doped to approximately 2 x 10 to the 17th/cu cm with silicon and is 0.3 microns thick.

  16. Static and dynamic magnetic property of MBE-grown Co2FeAl films

    NASA Astrophysics Data System (ADS)

    Qiao, Shuang; Nie, Shuaihua; Huo, Yan; Zhao, Jianhua; Wu, Yizheng; Zhang, Xinhui

    2014-08-01

    In this work, the static and dynamic magnetic properties of Co2FeAl films grown by molecular beam epitaxy (MBE) were studied by employing the magneto-optical Kerr rotation and ferromagnetic resonance (FMR) measurements. The growth temperature dependent magnetocrystalline anisotropy of MBE-grown Co2FeAl films were first investigated by employing the rotating magneto-optical Kerr effect. Then the magnetization dynamics and Gilbert damping property for high quality Co2FeAl films were investigated in detail by combining both the FMR and time-resolved magneto-optical Kerr rotation techniques. The apparent damping parameter was found to show strong dependence on the strength of the applied magnetic field at low-field regime, but decrease drastically with increasing magnetic field and eventually become a constant value of 0.004 at high-field regime. The inhomogeneity of magnetocrystalline anisotropy and two-magnon scattering are suggested to be responsible for the observed abnormal damping properties observed especially at low field regime. The intrinsic damping parameter of 0.004 is deduced for our highly-ordered Co2FeAl film. Our results provide essential information for highly-ordered MBE-grown Co2FeA film and its possible application in spintronic devices.

  17. Recent progress in MBE grown HgCdTe materials and devices at UWA

    NASA Astrophysics Data System (ADS)

    Gu, R.; Lei, W.; Antoszewski, J.; Madni, I.; Umana-Menbreno, G.; Faraone, L.

    2016-05-01

    HgCdTe has dominated the high performance end of the IR detector market for decades. At present, the fabrication costs of HgCdTe based advanced infrared devices is relatively high, due to the low yield associated with lattice matched CdZnTe substrates and a complicated cooling system. One approach to ease this problem is to use a cost effective alternative substrate, such as Si or GaAs. Recently, GaSb has emerged as a new alternative with better lattice matching. In addition, implementation of MBE-grown unipolar n-type/barrier/n-type detector structures in the HgCdTe material system has been recently proposed and studied intensively to enhance the detector operating temperature. The unipolar nBn photodetector structure can be used to substantially reduce dark current and noise without impeding photocurrent flow. In this paper, recent progress in MBE growth of HgCdTe infrared material at the University of Western Australia (UWA) is reported, including MBE growth of HgCdTe on GaSb alternative substrates and growth of HgCdTe nBn structures.

  18. Preliminary report on the MBE-4, an experimental multiple-beam induction linear accelerator for heavy ions

    SciTech Connect

    Warwick, A.I.; Gough, D.E.; Meuth, H.

    1988-11-01

    A small-scale experimental accelerator called MBE-4 has been constructed to demonstrate the principle of a current-amplifying induction linac for multiple beams of heavy ions. Four beams of Cs{sup 1+}, initially at 200 keV and each with a current of 10 mA have been accelerated and amplified to a kinetic energy of 700 keV and currents of 90 mA apiece. Transverse focusing is achieved by means of electrostatic quadrupoles; longitudinally the current is amplified and the beam bunch is held together against the space charge forces by special time-dependent accelerating fields. We report on the methods developed for designing and implementing the accelerating pulses and on measurements of the transverse and longitudinal emittance of the accelerated beams. Current fluctuations and the longitudinal emittance are initially almost zero and increase as acceleration errors are accumulated. We discuss the final longitudinal emittance and the current fluctuations in the experiment in terms of their acceptability for a large heavy-ion-fusion driver. 17 refs., 23 figs., 3 tabs.

  19. Picosecond spectroscopy of hydrogenated MBE-GaAs

    NASA Astrophysics Data System (ADS)

    Capizzi, M.; Coluzza, C.; Frankl, P.; Frova, A.; Colocci, M.; Gurioli, M.; Vinattieri, A.; Sacks, R. N.

    1991-04-01

    Picosecond-resolved and steady-state photoluminescence at LHe temperature in low-energy ion-gun hydrogenated GaAs/GaAlAs heterostructures are reported. The exciton in the GaAs layer shows an increase in lifetime - up to a factor of 3 - for moderate hydrogenation, followed by a sharp decrease below the value for the untreated sample, for higher H doses. Luminescence efficiency shows a consistent behavior. Incorporation of H generates a strong D-A band falling ˜64 meV below the gap energy. The behavior for heavy hydrogenation indicates the formation of a new type of deep defect, not ascribed to surface damage, because of the protective GaAlAs layer, plus the fact that the excitonic emission of the latter shows no variation.

  20. Arsenic p-Doping of HgCdTe Grown by Molecular Beam Epitaxy (MBE): A Solved Problem?

    NASA Astrophysics Data System (ADS)

    Garland, James W.; Grein, Christoph; Sivananthan, Sivalingam

    2013-11-01

    The goal of achieving well-controlled, reproducibly p-doped mercury cadmium telluride (HgCdTe) with sharp p- n junctions and low Shockley-Read-Hall contribution τ SRH to the minority carrier lifetime τ has been pursued for the past 30 years by the HgCdTe molecular beam epitaxial (MBE) growth community, but remains elusive. On the other hand, n-doping with In avoids the short τ SRH characteristic of arsenic-doped MBE-grown HgCdTe and is well controlled, stable, and reproducibly 100% activated as-grown. However, as discussed herein, because of inherent limitations of n-doped absorber layers, overcoming the challenges of successfully p-doping HgCdTe remains an important problem, especially for long-wavelength infrared detectors. We briefly review the achievements that have been made in p-doping HgCdTe, point out the reasons why achieving well-controlled, reproducibly p-doped MBE-grown HgCdTe with a lifetime τ not limited by τ SRH remains a very important task, discuss the probable origin of the short τ SRH in MBE-grown HgCdTe, and discuss possible ways to achieve much longer values of τ SRH in MBE-grown p-doped HgCdTe.

  1. Modified MBE hardware and techniques and role of gallium purity for attainment of two dimensional electron gas mobility >35×106 cm2/V s in AlGaAs/GaAs quantum wells grown by MBE

    NASA Astrophysics Data System (ADS)

    Gardner, Geoffrey C.; Fallahi, Saeed; Watson, John D.; Manfra, Michael J.

    2016-05-01

    We provide evidence that gallium purity is the primary impediment to attainment of ultra-high mobility in a two-dimensional electron gas (2DEG) in AlGaAs/GaAs heterostructures grown by molecular beam epitaxy (MBE). The purity of gallium can be enhanced dramatically by in-situ high temperature outgassing within an operating MBE. Based on analysis of data from an initial growth campaign in a new MBE system and modifications employed for a 2nd growth campaign, we have produced 2DEGs with low temperature mobility μ in excess of 35×106 cm2/V s at density n=3.0×1011/cm2 and μ=18×106 cm2/V s at n=1.1×1011/cm2. Our 2nd campaign data indicate that gallium purity remains the factor currently limiting μ<40×106 cm2/V s. We describe strategies to overcome this limitation.

  2. MBE based HgCdTe APDs and 3D LADAR sensors

    NASA Astrophysics Data System (ADS)

    Jack, Michael; Asbrock, Jim; Bailey, Steven; Baley, Diane; Chapman, George; Crawford, Gina; Drafahl, Betsy; Herrin, Eileen; Kvaas, Robert; McKeag, William; Randall, Valerie; De Lyon, Terry; Hunter, Andy; Jensen, John; Roberts, Tom; Trotta, Patrick; Cook, T. Dean

    2007-04-01

    Raytheon is developing HgCdTe APD arrays and sensor chip assemblies (SCAs) for scanning and staring LADAR systems. The nonlinear characteristics of APDs operating in moderate gain mode place severe requirements on layer thickness and doping uniformity as well as defect density. MBE based HgCdTe APD arrays, engineered for high performance, meet the stringent requirements of low defects, excellent uniformity and reproducibility. In situ controls for alloy composition and substrate temperature have been implemented at HRL, LLC and Raytheon Vision Systems and enable consistent run to run results. The novel epitaxial designed using separate absorption-multiplication (SAM) architectures enables the realization of the unique advantages of HgCdTe including: tunable wavelength, low-noise, high-fill factor, low-crosstalk, and ambient operation. Focal planes built by integrating MBE detectors arrays processed in a 2 x 128 format have been integrated with 2 x 128 scanning ROIC designed. The ROIC reports both range and intensity and can detect multiple laser returns with each pixel autonomously reporting the return. FPAs show exceptionally good bias uniformity <1% at an average gain of 10. Recent breakthrough in device design has resulted in APDs operating at 300K with essentially no excess noise to gains in excess of 100, low NEP <1nW and GHz bandwidth. 3D LADAR sensors utilizing these FPAs have been integrated and demonstrated both at Raytheon Missile Systems and Naval Air Warfare Center Weapons Division at China Lake. Excellent spatial and range resolution has been achieved with 3D imagery demonstrated both at short range and long range. Ongoing development under an Air Force Sponsored MANTECH program of high performance HgCdTe MBE APDs grown on large silicon wafers promise significant FPA cost reduction both by increasing the number of arrays on a given wafer and enabling automated processing.

  3. New MBE (molecular beam epitaxy) buffer used to eliminate backgating in gaas mesfets

    SciTech Connect

    Smith, F.W.; Calawa, A.R.; Chen, C.L.; Manfra, M.J.; Mahoney, L.J.

    1988-02-01

    A new buffer layer has been developed that eliminates backgating between MESFET's fabricated in active layers grown upon it. The new buffer is grown by molecular beam epitaxy (MBE) at low substrate temperatures (150-300 C) using Ga and As4 beam fluxes. It is highly resistive, optically inactive, and crystalline, and high-quality GaAs active layers can be grown on top of the new buffer. MESFET's fabricated in active layers grown on top of this new buffer show improved output resistance and breakdown voltages; the dc and Rf characteristics are otherwise comparable to MESFET's fabricated by alternative means and with other buffer layers.

  4. Fabrication of photonic crystal lasers by MBE air-hole retained growth

    NASA Astrophysics Data System (ADS)

    Nishimoto, Masaya; Ishizaki, Kenji; Maekawa, Kyohei; Liang, Yong; Kitamura, Kyoko; Noda, Susumu

    2014-09-01

    We report the fabrication of photonic crystal surface-emitting lasers using an MBE air-hole retained growth method. We demonstrate the achievement of single-mode oscillation and observe a single-lobed, linearly polarized beam. We also use three-dimensional coupled wave analysis to calculate the effects of using different air-hole shapes, which determine the beam shape and polarization. A single-lobed, linearly polarized beam can be obtained by modifying the air holes from circular to a tilted-corn shape after growth.

  5. Experimental investigation of MBE GaAs rib waveguides at 10.6 microns

    NASA Astrophysics Data System (ADS)

    Sarkis, R. G.; Larson, D. C.; Jenkinson, H. A.

    1989-10-01

    Results are evaluated from recent investigations of the performance of n/n(+)-GaAs rib waveguides fabricated by MBE and reactive-ion etching. A simple, 'effective index' analysis method is used to predict bound-mode propagation constants; a comparison with alternative analyses shows the method to be sufficiently accurate for the geometries in question. Intensity curves are obtained experimentally as a function of incident angle, for correlation with theoretical, lower-order modes. A prism-coupling approach is developed which not only allows experimenters to excite and observe the bands of a rib waveguide, but to empirically determine their values.

  6. Self-organized MBE growth of II VI epilayers on patterned GaSb substrates

    NASA Astrophysics Data System (ADS)

    Wissmann, H.; Tran Anh, T.; Rogaschewski, S.; von Ortenberg, M.

    1999-05-01

    We report on the self-organized MBE growth of II-VI epilayers on patterned and unpatterned GaSb substrates resulting in quantum wires and quantum wells, respectively. The HgSe : Fe quantum wires were grown on (0 0 1)GaSb substrates with a buffer of lattice-matched ZnTe 1- xSe x. Due to the anisotropic growth of HgSe on the A-oriented stripes roof-like overgrowth with a definite ridge was obtained. Additional Fe doping in the direct vicinity of the ridge results in a highly conductive quantum wire.

  7. Si-doped GaAs/AlGaAs TJS laser by MBE

    SciTech Connect

    Mitsunaga, K.; Fujiwara, K.; Nunoshita, M.; Nakayama, T.

    1984-04-01

    The effect of high temperature annealing on the properties of silicon-doped GaAs/AlGaAs double heterostructure (DH) grown by molecular beam expitaxy (MBE)= and its application to the fabrication of transverse junction stripe (TJS) lasers are reported. In spite of the amphoteric nature of Si, it was found that the high temperature annealing gave little influence on the electrical and optical quality of the n-type DH wafer. The TJS laser using Si-doped GaAs/AlGaAs wafer has been oscillated cw at room temperature and exhibited low threshold current of 30 mA and high quantum efficiency of 60%.

  8. Hydrogen sulphide doping of GaAs and AlxGa1-xAs grown by molecular beam epitaxy (MBE)

    NASA Astrophysics Data System (ADS)

    Briones, F.; Golmayo, D.; González, L.; de Miguel, J. L.

    1985-03-01

    H2S gas has been used during molecular beam epitaxy (MBE) growth of GaAs and Al x Ga1- x As as sulphur vector for n-type doping. Doping efficiencies are less than 10-3 at usual growth temperatures, and are limited by an incorporation competitive surface process, probably 2Ga+H2S→Ga2S+H2. In AlxGa1- x As for x≧0.2 the doping efficiency is further reduced by carrier freeze-out at deep levels. Measured thermal activation energies depend on growth conditions and remain relatively low even up to the direct-indirect bandgap crossover for substrate temperatures in the 585 645 ‡C range.

  9. MBE growth of HgCdTe avalanche photodiode structures for low-noise 1.55 μm photodetection

    NASA Astrophysics Data System (ADS)

    de Lyon, T. J.; Baumgratz, B.; Chapman, G.; Gordon, E.; Hunter, A. T.; Jack, M.; Jensen, J. E.; Johnson, W.; Johs, B.; Kosai, K.; Larsen, W.; Olson, G. L.; Sen, M.; Walker, B.; Wu, O. K.

    1999-05-01

    Molecular-beam epitaxy (MBE) has been utilized to fabricate HgCdTe heterostructure separate absorption and multiplication avalanche photodiodes (SAM-APD) sensitive to infrared radiation in the 1.1-1.6 μm spectral range, as an alternative technology to existing III-V APD detectors. Device structures were grown on CdZnTe(211)B substrates using CdTe, Te, and Hg sources with in situ In and As doping. The composition of the HgCdTe alloy layers was adjusted to achieve both efficient absorption of IR radiation in the 1.1-1.6 μm spectral range and low excess-noise avalanche multiplication. The Hg 1- xCd xTe alloy composition in the gain region of the device, x=0.73, was selected to achieve equality between the bandgap energy and spin-orbit splitting to resonantly enhance the impact ionization of holes in the split-off valence band. The appropriate value of this alloy composition was determined from analysis of the 300 K bandgap and spin-orbit splitting energies of a set of calibration layers, using a combination of IR transmission and spectroscopic ellipsometry measurements. MBE-grown APD epitaxial wafers were processed into passivated mesa-type discrete device structures and diode mini-arrays using conventional HgCdTe process technology. Device spectral response, dark current density, and avalanche gain measurements were performed on the processed wafers. Avalanche gains in the range of 30-40 at reverse bias of 85-90 V and array-median dark current density below 2×10 -4 A/cm 2 at 40 V reverse bias have been demonstrated.

  10. MBE Growth of Ferromagnetic Metal/Compound Semiconductor Heterostructures for Spintronics

    ScienceCinema

    Palmstrom, Chris [University of California, Santa Barbara, California, United States

    2010-01-08

    Electrical transport and spin-dependent transport across ferromagnet/semiconductor contacts is crucial in the realization of spintronic devices. Interfacial reactions, the formation of non-magnetic interlayers, and conductivity mismatch have been attributed to low spin injection efficiency. MBE has been used to grow epitaxial ferromagnetic metal/GA(1-x)AL(x)As heterostructures with the aim of controlling the interfacial structural, electronic, and magnetic properties. In situ, STM, XPS, RHEED and LEED, and ex situ XRD, RBS, TEM, magnetotransport, and magnetic characterization have been used to develop ferromagnetic elemental and metallic compound/compound semiconductor tunneling contacts for spin injection. The efficiency of the spin polarized current injected from the ferromagnetic contact has been determined by measuring the electroluminescence polarization of the light emitted from/GA(1-x)AL(x)As light-emitting diodes as a function of applied magnetic field and temperature. Interfacial reactions during MBE growth and post-growth anneal, as well as the semiconductor device band structure, were found to have a dramatic influence on the measured spin injection, including sign reversal. Lateral spin-transport devices with epitaxial ferromagnetic metal source and drain tunnel barrier contacts have been fabricated with the demonstration of electrical detection and the bias dependence of spin-polarized electron injection and accumulation at the contacts. This talk emphasizes the progress and achievements in the epitaxial growth of a number of ferromagnetic compounds/III-V semiconductor heterostructures and the progress towards spintronic devices.

  11. Thermal stability of MBE-grown epitaxial MoSe2 and WSe2 thin films

    NASA Astrophysics Data System (ADS)

    Chang, Young Jun; Choy, Byoung Ki; Phark, Soo-Hyon; Kim, Minu

    Layered transition metal dichalcogenides (TMDs) draw much attention, because of its unique optical properties and band structures depending on the layer thicknesses. However, MBE growth of epitaxial films demands information about thermal stability of stoichiometry and related electronic structure for high temperature range. We grow epitaxial MoSe2 and WSe2 ultrathin films by using molecular beam epitaxy (MBE). We characterize stoichiometry of films grown at various growth temperature by using various methods, XPS, EDX, and TOF-MEIS. We further test high temperature stability of electronic structure for those films by utilizing in-situ ellipsometry attached to UHV chamber. We discuss threshold temperatures up to 700~1000oC, at which electronic phases changes from semiconductor to metal due to selenium deficiency. This information can be useful for potential application of TMDs for fabrication of Van der Waals multilayers and related devices. This research was supported by Nano.Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning. (2009-0082580), NRF-2014R1A1A1002868.

  12. MBE Growth of Ferromagnetic Metal/Compound Semiconductor Heterostructures for Spintronics

    SciTech Connect

    Palmstrom, Chris

    2009-07-01

    Electrical transport and spin-dependent transport across ferromagnet/semiconductor contacts is crucial in the realization of spintronic devices. Interfacial reactions, the formation of non-magnetic interlayers, and conductivity mismatch have been attributed to low spin injection efficiency. MBE has been used to grow epitaxial ferromagnetic metal/GA(1-x)AL(x)As heterostructures with the aim of controlling the interfacial structural, electronic, and magnetic properties. In situ, STM, XPS, RHEED and LEED, and ex situ XRD, RBS, TEM, magnetotransport, and magnetic characterization have been used to develop ferromagnetic elemental and metallic compound/compound semiconductor tunneling contacts for spin injection. The efficiency of the spin polarized current injected from the ferromagnetic contact has been determined by measuring the electroluminescence polarization of the light emitted from/GA(1-x)AL(x)As light-emitting diodes as a function of applied magnetic field and temperature. Interfacial reactions during MBE growth and post-growth anneal, as well as the semiconductor device band structure, were found to have a dramatic influence on the measured spin injection, including sign reversal. Lateral spin-transport devices with epitaxial ferromagnetic metal source and drain tunnel barrier contacts have been fabricated with the demonstration of electrical detection and the bias dependence of spin-polarized electron injection and accumulation at the contacts. This talk emphasizes the progress and achievements in the epitaxial growth of a number of ferromagnetic compounds/III-V semiconductor heterostructures and the progress towards spintronic devices.

  13. Impact of Tellurium Precipitates in CdZnTe Substrates on MBE HgCdTe Deposition

    NASA Astrophysics Data System (ADS)

    Benson, J. D.; Bubulac, L. O.; Smith, P. J.; Jacobs, R. N.; Markunas, J. K.; Jaime-Vasquez, M.; Almeida, L. A.; Stoltz, A.; Wijewarnasuriya, P. S.; Brill, G.; Chen, Y.; Peterson, J.; Reddy, M.; Vilela, M. F.; Johnson, S. M.; Lofgreen, D. D.; Yulius, A.; Bostrup, G.; Carmody, M.; Lee, D.; Couture, S.

    2014-11-01

    State-of-the-art (112)B CdZnTe substrates were examined for near-surface tellurium precipitate-related defects. The Te precipitate density was observed to be fairly uniform throughout the bulk of the wafer, including the near-surface region. After a molecular beam epitaxy (MBE) preparation etch, exposed Te precipitates, small pits, and bumps on the (112)B surface of the CdZnTe wafer were observed. From near-infrared and dark field microscopy, the bumps and small pits on the CdZnTe surface are associated with strings of Te precipitates. Raised bumps are Te precipitates near the surface of the (112)B CdZnTe where the MBE preparation etch has not yet exposed the Te precipitate(s). An exposed Te precipitate sticking above the etched CdZnTe surface plane occurs when the MBE preparation etch rapidly undercuts a Te precipitate. Shallow surface pits are formed when the Te precipitate is completely undercut from the surrounding (112)B surface plane. The Te precipitate that was previously located at the center of the pit is liberated by the MBE preparation etch process.

  14. MBE Grown In x Ga1- x N Thin Films with Bright Visible Emission Centered at 550 nm

    NASA Astrophysics Data System (ADS)

    Dasari, K.; Thapa, B.; Wang, J.; Wright, J.; Kaya, S.; Jadwisienczak, W. M.; Palai, R.

    2016-04-01

    The In x Ga1- x N thin films with indium content of x = 14-18 at.% were successfully grown by using molecular beam epitaxy (MBE) at high growth temperatures from 650°C to 800°C. In situ reflection high-energy electron diffraction (RHEED) of the In x Ga1- x N films confirmed the Stranski-Krastanov growth mode. X-ray diffraction (XRD) of the films confirmed their highly crystalline nature having c-axis orientation with a small fraction of secondary InN phase admixture. High-resolution cross-sectional scanning electron microscopy images showed two-dimensional epilayers growth with thickness of about ˜260 nm. The high growth temperature of In x Ga1- x N epilayers is found to be favorable to facilitate more GaN phase than InN phase. All the fundamental electronic states of In, Ga, and N were identified by x-ray photoelectron spectroscopy (XPS) and the indium composition has been calculated from the obtained XPS spectra with CASAXPS software. The composition calculations from XRD, XPS and photoluminescence closely match each other. The biaxial strain has been calculated and found to be increasing with the In content. Growing In x Ga1- x N at high temperatures resulted in the reduction in stress/strain which affects the radiative electron-hole pair recombination. The In x Ga1- x N film with lesser strain showed a brighter and stronger green emission than films with the larger built-in strain. A weak S-shaped near band edge emission profile confirms the relatively homogeneous distribution of indium.

  15. Structural, electronic and mechanical properties of alkaline earth metal oxides MO (M=Be, Mg, Ca, Sr, Ba)

    NASA Astrophysics Data System (ADS)

    Cinthia, A. Jemmy; Priyanga, G. Sudha; Rajeswarapalanichamy, R.; Iyakutti, K.

    2015-04-01

    The structural, electronic and mechanical properties of alkaline earth metal oxides MO (M=Be, Mg, Ca, Sr, Ba) in the cubic (B1, B2 and B3) phases and in the wurtzite (B4) phase are investigated using density functional theory calculations as implemented in VASP code. The lattice constants, cohesive energy, bulk modulus, band structures and the density of states are computed. The calculated lattice parameters are in good agreement with the experimental and the other available theoretical results. Electronic structure reveals that all the five alkaline earth metal oxides exhibit semiconducting behavior at zero pressure. The estimated band gaps for the stable wurtzite phase of BeO is 7.2 eV and for the stable cubic NaCl phases of MgO, CaO, SrO and BaO are 4.436 eV, 4.166 eV, 4.013 eV, and 2.274 eV respectively. A pressure induced structural phase transition occurs from wurtzite (B4) to NaCl (B1) phase in BeO at 112.1 GPa and from NaCl (B1) to CsCl (B2) phase in MgO at 514.9 GPa, in CaO at 61.3 GPa, in SrO at 42 GPa and in BaO at 14.5 GPa. The elastic constants are computed at zero and elevated pressures for the B4 and B1 phases for BeO and for the B1 and B2 phases in the case of the other oxides in order to investigate their mechanical stability, anisotropy and hardness. The sound velocities and the Debye temperatures are calculated for all the oxides using the computed elastic constants.

  16. Drift compression experiments on MBE-4 and related emittance growth phenomena

    SciTech Connect

    Eylon, S.; Faltens, A.; Fawley, W.; Garvey, T.; Hahn, K.; Henestroza, E.; Smith, L.

    1991-04-01

    We have recently conducted a series of experiments on the MBE-4 heavy ion accelerator in which a velocity tilt was placed on the beam in the first accelerating section beyond the injector, followed by drift compression over the remaining 11 meters. Depending upon the magnitude of the velocity tilt and the accompanying mismatch in the focusing lattice, emittance growth was observed, manifested by butterfly'' shapes in x {minus} x{prime} phase space. We discuss various analytical limits on ion beam compression and relate them to these experiments and also to a driver for a heavy ion fusion reactor. We also present numerical simulations which investigate various aspects of compression and consequent emittance growth. 2 refs., 3 figs., 1 tab.

  17. An overview of hgcdte mbe defects and analysis of defect size

    NASA Astrophysics Data System (ADS)

    Olsson, Kurt Robert

    HgCdTe is the most widely used material for high performance infrared detection applications. Growth of HgCdTe epitaxial layers by molecular beam epitaxy (MBE) has ushered in advanced devices that take advantage of the unique properties of the material. Formation of defects during the growth process is one of the largest drawbacks to this technology, and must be minimized to increase device operability. In this paper, the defects encountered in HgCdTe are categorized, along with formation mechanisms and possible means of reduction. A new method of defect identification is proposed, which takes advantage of full wafer defect mapping capabilities. A correlation between the thickness of the grown film and the size of defects initiated at the substrate surface is found. This allows further defect information to be extracted from the size and density of the defects.

  18. Surface structure transitions on (0 0 1) GaAs during MBE

    NASA Astrophysics Data System (ADS)

    Preobrazhenskii, V. V.; Putyato, M. A.; Pchelyakov, O. P.; Semyagin, B. R.

    1999-05-01

    Experimental phase diagrams of GaAs (0 0 1) surface were obtained by direct measuring of the As 4 flux and the substrate temperature. The infringement of the epitaxial growth was found to occur at the ratio of As 4 to Ga fluxes less than or equal to 0.25. Hence, the As 4 incorporation coefficient is close to unity during MBE. A diffusion model was suggested to describe positions of boundaries between surface structures (SS) in the phase diagrams. Dependencies of temperatures of SS transitions on the rate of surface heating in the absence of incident fluxes were obtained. The transition temperatures were discovered to tend to constant values as the heating rate increased. A model underlying this dependence was developed.

  19. Polycrystalline ZnS(x)Se(1 - x) thin films deposited on ITO glass by MBE.

    PubMed

    Shen, Da-Ke; Sou, I K; Han, Gao-Rong; Du, Pi-Yi; Que, Duan-Lin

    2003-01-01

    MBE growth of ZnS(x)Se(1 - x) thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging from 270 degrees C to 330 degrees C . The XRD theta/2theta spectra resulted from these films indicated that the as-grown polycrystalline ZnS(x)Se(1 - x) thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 degrees C. Both AFM and TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnS(x)Se(1 - x) thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional micrograph showing a well defined columnar structure. PMID:12659224

  20. The Mid-Barremian Event (MBE): the Prelude to the OAE1a

    NASA Astrophysics Data System (ADS)

    Coccioni, R.; Galeotti, S.; Sprovieri, M.

    2003-12-01

    Detailed litho-, bio- and chemostratigraphic investigations of the Hauterivian-lowermost Aptian Maiolica pelagic limestones in the Umbria-Marche sequence, allowed to identify that the Selli Level, which is the regional sedimentary expression of the OAE 1a, represents the climax of a ca. 5 myr-long cycle of black shale deposition starting at the lower/upper Barremian boundary within polarity Chronozone M3 and H. similis-H. kutznetsovae planktonic foraminiferal Zone, that is in the lowermost part of the calcareous nannofossil Zone NC 5D. This long-term cycle starts with a prominent short-term event, here named mid-Barremian Event (MBE), which is associated with several changes in the biotic and abiotic records. In particular, a comparison of the available chemo- litho-, and biostratigraphic data from the Umbria-Marche Basin, allows to recognise that the MBE is defined by: 1) a 0.5 per mil positive shift in the carbon isotope values (Hadji, 1993; unpublished data); 2) a major step in the initial evolutive radiation of planktonic foraminifera (unpublished data); 3) a major turnover in the radiolarian assemblages (Jud, 1994; O'Dogherty, 1994). The above mentioned change in carbon isotope values can be confidently correlated over the Mediterranean Tethys which is the sole area where a detailed isotopic record is available for the entire Barremian (Erba et al., 1999; Wissler et al., 2002). These lines of evidence concur to define the MBE as an outstanding event associated with large scale changes in the ocean-climate system likely related to the rapid oceanic Ontong-Java Plateau formation, which eventually led to OAE1a. Remarkably, the MBE largely predates the well known series of biotic and geochemical events occurring prior to the OAE1a and may be considered as the real turning point in the Barremian-Aptian long-term cycle of black-shale deposition and evolutionary turnovers in several fossil groups. References Erba, E., Channell, J.E.T., Claps, M., Jones, C., Larson, R

  1. Nitride-MBE system for in situ synchrotron X-ray measurements

    NASA Astrophysics Data System (ADS)

    Sasaki, Takuo; Ishikawa, Fumitaro; Yamaguchi, Tomohiro; Takahasi, Masamitu

    2016-05-01

    A molecular beam epitaxy (MBE) chamber dedicated to nitride growth was developed at the synchrotron radiation facility SPring-8. This chamber has two beryllium windows for incident and outgoing X-rays, and is directly connected to an X-ray diffractometer, enabling in situ synchrotron X-ray measurements during the nitride growth. Experimental results on initial growth dynamics in GaN/SiC, AlN/SiC, and InN/GaN heteroepitaxy were presented. We achieved high-speed and high-sensitivity reciprocal space mapping with a thickness resolution of atomic-layer scale. This in situ measurement using the high-brilliance synchrotron light source will be useful for evaluating structural variations in the initial growth stage of nitride semiconductors.

  2. Desorption mass spectrometry: Revisiting the in-situ calibration technique for mixed group-V alloy MBE growth of ~3.3 μm diode lasers

    NASA Astrophysics Data System (ADS)

    Kaspi, Ron; Lu, Chunte; Yang, Chi; Newell, Timothy C.; Luong, Sanh

    2015-09-01

    We apply the desorption mass spectrometry (DMS) technique and analyze the desorbed Sb species in-situ during MBE growth of mixed As/Sb heterostructures. We demonstrate how DMS is useful in pre-growth calibration of the V/III ratio, the group-III ratio, as well as the Sb-content in quaternary or quinary mixed As/Sb alloys. We also apply DMS to the digital alloy growth method. For demonstration purposes, we start with an un-calibrated MBE system, use the DMS technique to calibrate all of the previously undetermined MBE parameters and grow a ~3.3 μm diode laser heterostructure in only one attempt. The results demonstrate that the DMS technique will allow the MBE to quickly converge toward a set of acceptable growth parameters without the need for ex-situ calibration of alloy composition.

  3. Specific features of NH{sub 3} and plasma-assisted MBE in the fabrication of III-N HEMT heterostructures

    SciTech Connect

    Alexeev, A. N.; Krasovitsky, D. M.; Petrov, S. I.; Chaly, V. P.; Mamaev, V. V.; Sidorov, V. G.

    2015-01-15

    The specific features of how nitride HEMT heterostructures are produced by NH{sub 3} and plasma-assisted (PA) molecular-beam epitaxy (MBE) are considered. It is shown that the use of high-temperature AlN/AlGaN buffer layers grown with ammonia at extremely high temperatures (up to 1150°C) can drastically improve the structural perfection of the active GaN layers and reduce the dislocation density in these layers to values of 9 × 10{sup 8}−1 × 10{sup 9} cm{sup −2}. The use of buffer layers of this kind makes it possible to obtain high-quality GaN/AlGaN heterostructures by both methods. At the same time, in contrast to ammonia MBE which is difficult to apply at T < 500°C (because of the low efficiency of ammonia decomposition), PA MBE is rather effective at low temperatures, e.g., for the growth of InAlN layers lattice-matched with GaN. The results obtained in the MBE growth of AlN/AlGaN/GaN/InAlN heterostructures by both PA-MBE and NH{sub 3}-MBE with an extremely high ammonia flux are demonstrated.

  4. MBE growth of active regions for electrically pumped, cw-operating GaSb-based VCSELs

    NASA Astrophysics Data System (ADS)

    Kashani-Shirazi, K.; Bachmann, A.; Boehm, G.; Ziegler, S.; Amann, M.-C.

    2009-03-01

    Electrically pumped, cw-operating, single-mode GaSb-based VCSELs are attractive light sources for trace-gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS) [A. Vicet, D.A. Yarekha, A. Pérona, Y. Rouillard, S. Gaillard, Spectrochimica Acta Part A 58 (2002) 2405-2412]. Only recently, the first electrically pumped (EP) devices emitting at 2.325 μm in cw-mode at room temperature have been reported [A. Bachmann, T. Lim, K. Kashani-Shirazi, O. Dier, C. Lauer, M.-C. Amann, Electronics Letters 44(3) (2008) 202-203]. The fabrication of these devices employs the molecular beam epitaxy (MBE) growth of GaSb/AlAsSb-distributed Bragg mirrors, a multi-quantum-well active region made of AlGaAsSb/InGaAsSb and an InAsSb/GaSb-buried-tunnel junction. As VCSELs are usually driven under high injection rates, an optimum electrical design of active regions is essential for high-performance devices. In this paper we present an enhanced simulation of current flow in the active region under operation conditions. The calculation includes carrier transport by drift, diffusion and tunneling. We discuss different design criteria and material compositions for active regions. Active regions with various barrier materials were incorporated into edge emitter samples to evaluate their performance. Aluminum-containing barriers show better internal efficiency compared to active regions with GaSb as the barrier material.

  5. MBE fabrication of self-assembled Si and metal nanostructures on Si surfaces

    SciTech Connect

    Galiana, Natalia; Martin, Pedro-Pablo; Munuera, Carmen; Varela del Arco, Maria; Soria, Federico; Ocal, Carmen; Ruiz, Ana; Alonso, Maria

    2006-01-01

    Two types of fairly regular distributions of Si nanostructures, of interest as templates to grow spatially controlled ensembles of metal (Co, Fe, Ag, etc.) nanostructures, are presented in this paper. Both of them are achieved by self-assembling processes during Si homoepitaxy. One corresponds to films grown by molecular beam epitaxy (MBE) on Si(0 0 1)-2 x 1 surfaces with low (<1 degree) miscut angles. In this case, arrays of 3D Si-islands displaying well defined pyramid-like shapes can be obtained, as evidenced by Scanning Force Microscopy (SFM) and Scanning Transmission Electron Microscopy (STEM). Such arrays exhibit strong similarities with those reported for Ge and SiGe islands on Si(0 0 1), and may thus serve as a simpler route to produce ordered distributions of metallic nanodots. On the other hand, on Si(1 1 1)-7 x 7 vicinal substrates misoriented 4 degrees toward the View the MathML source direction, step rearrangement during homoepitaxy permits to produce nanopatterned surfaces, the building-blocks of which are triangular (1 1 1) platforms, with lateral dimensions of hundreds of nanometers, bound by step bunches about 30 nm high. Furthermore, different Ag deposition experiments support this spontaneous patterning on Si(1 1 1) as a promising approach to achieve regular distributions of metallic nanocrystals with an overall homogeneity in sizes, shapes and spacing.

  6. Ga-assisted MBE growth of GaAs nanowires using thin HSQ layer

    NASA Astrophysics Data System (ADS)

    Rieger, Torsten; Heiderich, Sonja; Lenk, Steffi; Lepsa, Mihail Ion; Grützmacher, Detlev

    2012-08-01

    We present detailed results about the molecular beam epitaxy (MBE) growth of GaAs nanowires (NWs) on GaAs (111)B substrates prepared for the growth by a new method using hydrogen silsesquioxane (HSQ). Before the growth, HSQ is converted to SiOx by thermal treatment. The NWs are grown via the vapor-liquid-solid (VLS) mechanism. The influence of five growth parameters are described: SiOx thickness, growth time, substrate temperature and Ga and As4 beam fluxes. It is shown that the nanowire density can be tuned by two orders of magnitude by adjusting the SiOx thickness. Additionally, the results demonstrate that the axial growth is controlled by the As4 beam flux whereas the lateral growth is controlled by the Ga beam flux. The observed NW tapering is mainly determined by the V/III beam flux ratio. Our study gives important information about the VLS growth mechanism, which is extended by considering the secondary adsorption process of Ga adatoms. The nanowires have predominantly zinc blende crystal structure with rotational twins. A wurtzite segment is always found at the top of the NWs being associated with the growth after the Ga shutter has been closed.

  7. Group III-nitride thin films grown using MBE and bismuth

    DOEpatents

    Kisielowski, Christian K.; Rubin, Michael

    2002-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  8. Group III-nitride thin films grown using MBE and bismuth

    DOEpatents

    Kisielowski, Christian K.; Rubin, Michael

    2000-01-01

    The present invention comprises growing gallium nitride films in the presence of bismuth using MBE at temperatures of about 1000 K or less. The present invention further comprises the gallium nitride films fabricated using the inventive fabrication method. The inventive films may be doped with magnesium or other dopants. The gallium nitride films were grown on sapphire substrates using a hollow anode Constricted Glow Discharge nitrogen plasma source. When bismuth was used as a surfactant, two-dimensional gallium nitride crystal sizes ranging between 10 .mu.m and 20 .mu.m were observed. This is 20 to 40 times larger than crystal sizes observed when GaN films were grown under similar circumstances but without bismuth. It is thought that the observed increase in crystal size is due bismuth inducing an increased surface diffusion coefficient for gallium. The calculated value of 4.7.times.10.sup.-7 cm.sup.2 /sec. reveals a virtual substrate temperature of 1258 K which is 260 degrees higher than the actual one.

  9. MBE growth and characterization of TlInGaAsN double quantum well structures

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, D.; Shanthi, S.; Kim, K. M.; Sakai, Y.; Ishimaru, M.; Hasegawa, S.; Asahi, H.

    2009-03-01

    In the pursuit of reducing the temperature dependence of the emission wavelengths of devices, TlInGaAsN double quantum well (DQW) structures with different barriers grown on GaAs substrates by molecular beam epitaxy (MBE) were investigated. Higher Tl incorporation, a key parameter to reduce temperature dependence, could be obtained in the TlGaAsN barrier samples. However, the presence of many dislocations and very rough interfaces together with phase separation reduced the photoluminescence (PL) characteristics. DQW structures with combined barriers of TlGaAsN+TlGaAs+TlGaAsN and those consisting of TlGaAsN with reduced N composition showed improved crystalline characteristics. The (2 2 4) reciprocal space maps of these two samples did not show any diffraction corresponding to phase segregation. However, cross-sectional transmission electron microscopy (X-TEM) images revealed the presence of inhomogeneity (i.e., the presence of nearly perfect regions with good interfaces as well as regions with rough interfaces) in these samples.

  10. Characterization of ZnSe homo-interface grown by MBE

    NASA Astrophysics Data System (ADS)

    Nakanishi, F.; Doi, H.; Yamada, T.; Matsuoka, T.; Nishine, S.; Matsumoto, K.; Shirakawa, T.

    1997-06-01

    A ZnSe homo-interface, which was formed by MBE, was characterized. First, when the unetched ZnSe substrates were used, 3D-nucleation occurred, which suggested the remnant of the heterogeneous nuclei. Consequently, the interface layer was clearly visible and as high as 10 8 cm -2 crystal defects, such as dislocations and stacking faults, were observed by cross sectional TEM. The EPD was uncountable at this high defect density. Second, when the substrates were chemically etched, 2D-nucleation was confirmed by RHEED, and interface layer and defects were not observed by cross sectional TEM. However plan-view TEM and EPD revealed that about 10 6-10 7 cm -2 crystal defects were observed. To clarify the origin of the crystal defects at the homo-interface, SIMS analysis was performed and the results showed the pile up of oxygen at the interface, and the EPD was proportional to the intensity of the O signal. Finally, the reduction of the oxide layer after the chemical etching was tried using various reagents. The reconstruction pattern of the RHEED was observed at lower temperatures using HCl solution and the EPD was lowered near the level of the ZnSe substrates, 10 4-10 5 cm -2

  11. MBE fabrication of self-assembled Si and metal nanostructures on Si surfaces

    NASA Astrophysics Data System (ADS)

    Galiana, Natalia; Martin, Pedro-Pablo; Munuera, Carmen; Varela, María; Soria, Federico; Ocal, Carmen; Ruiz, Ana; Alonso, María

    2006-09-01

    Two types of fairly regular distributions of Si nanostructures, of interest as templates to grow spatially controlled ensembles of metal (Co, Fe, Ag, etc.) nanostructures, are presented in this paper. Both of them are achieved by self-assembling processes during Si homoepitaxy. One corresponds to films grown by molecular beam epitaxy (MBE) on Si(0 0 1)-2 × 1 surfaces with low (<1°) miscut angles. In this case, arrays of 3D Si-islands displaying well defined pyramid-like shapes can be obtained, as evidenced by Scanning Force Microscopy (SFM) and Scanning Transmission Electron Microscopy (STEM). Such arrays exhibit strong similarities with those reported for Ge and SiGe islands on Si(0 0 1), and may thus serve as a simpler route to produce ordered distributions of metallic nanodots. On the other hand, on Si(1 1 1)-7 × 7 vicinal substrates misoriented 4° toward the [1 1 2¯] direction, step rearrangement during homoepitaxy permits to produce nanopatterned surfaces, the building-blocks of which are triangular (1 1 1) platforms, with lateral dimensions of hundreds of nanometers, bound by step bunches about 30 nm high. Furthermore, different Ag deposition experiments support this spontaneous patterning on Si(1 1 1) as a promising approach to achieve regular distributions of metallic nanocrystals with an overall homogeneity in sizes, shapes and spacing.

  12. High quality, hybrid-MBE growth of SrVO3 thin films

    NASA Astrophysics Data System (ADS)

    Moyer, Jarrett; Eaton, Craig; Engel-Herbert, Roman

    2013-03-01

    Vanadium-based transition metal oxides are an intriguing class of materials to study due to the metal-to-insulator (MIT) transitions that arise in many of the binary oxides (i.e. VO2, V2O3, V2O5) . The perovskite SrVO3 is metallic in bulk; however, it is possible to induce an MIT by modulating the bandwidth through strain or dimensional confinement. A mandatory requirement for controlling the electronic phase transition properties in material systems with strong correlation is the growth of high quality, stoichiometric thin films. This is demonstrated here with the growth of SrVO3 on LSAT (001) substrates using a hybrid-MBE technique, where the Sr is evaporated from an effusion cell and the V is provided through the metal-organic precursor vanadium oxo-tri-isopropoxide (VTIP). The structural properties of films with varying VTIP:Sr ratios are characterized by RHEED, XRD, AFM and TEM. These measurements demonstrate that SrVO3 can be grown with excellent structural quality, atomically flat surfaces and rocking curves of the same width as the substrate, accomplishing a necessary first step in controlling the MIT in SrVO3. This research is primarily supported by ONR Grant N00014-11-1-0665

  13. MCT by MBE on GaAs at AIM: state of the art and roadmap

    NASA Astrophysics Data System (ADS)

    Figgemeier, Heinrich; Wenisch, Jan; Eich, Detlef; Hanna, Stefan; Schirmacher, Wilhelm; Lutz, Holger; Schallenberg, Timo; Breiter, Rainer

    2015-06-01

    In multiple publications over the last years, MCT MBE on GaAs has been shown to be a very versatile and promising material system and indeed may be the prime candidate among the alternative substrates for the fabrication of high-performance detectors across the whole IR composition range. In this paper we report on successful growth of MCT on GaAs over the composition range 0.2 < x(Cd) < 0.8. A single color MWIR 640 × 512, 15 μm pitch detector fabricated from this material with an operability of 99.71% at an operating temperature of 120 K is presented. In the LWIR region, an operability of 99.48% at 65 K has been achieved with a 1280 × 1024, 15 μm pitch detector. Finally we report on preliminary results of a dual-color 640 × 512, 20 μm pitch detector with cutoff wavelengths in the 3 - 4 and 4 - 5 μm range.

  14. Controlling the compositional inhomogeneities in AlxGa1-xN/AlyGa1-yN MQWs grown by PA-MBE: Effect on luminescence properties

    NASA Astrophysics Data System (ADS)

    Pramanik, Pallabi; Sen, Sayantani; Singha, Chirantan; Roy, Abhra Shankar; Das, Alakananda; Sen, Susanta; Bhattacharyya, Anirban; Kumar, Deepak; Sridhara Rao, D. V.

    2016-04-01

    Al0.35Ga0.65N/Al0.55Ga0.45N MQWs were grown by PA-MBE using a range of group III/V flux ratios. TEM images indicate sharp interfaces and well/barrier widths of 1.5/2 nm. We observe that small variations of group III/V flux ratio cause dramatic variations in the room temperature photoluminescence (PL) spectra. In addition to band edge luminescence, multiple low energy PL peaks are observed for growths under excess group III conditions, which are absent for near-stoichiometric growth. Temperature dependent PL measurements indicate that at room temperature, emission occurs due to transitions at potential fluctuations generated by the presence of compositional inhomogeneity. These effects are dominant for growth under excess group III conditions due to the presence of a metallic layer on the growth surface during deposition. This can be eliminated by the use of an Indium surfactant during growth, which modifies the diffusion length of Ga and Al adatoms. Under these conditions, the optical properties of MQWs are relatively insensitive to variations in group III to V flux ratio and hence substrate temperature, thus making them suitable for industrial-scale fabrication of optoelectronic devices in the ultraviolet range.

  15. MBE grown III-V strain relaxed buffer layers and superlattices characterized by atomic force microscopy

    SciTech Connect

    Howard, A.J.; Fritz, I.J.; Drummond, T.J.; Olsen, J.A.; Hammons, B.E.; Kurtz, S.R.; Brennan, T.M.

    1993-11-01

    Using atomic force microscopy (AFM), the authors have investigated the effects of growth temperature and dopant incorporation on the surface morphology of MBE grown graded buffer layers and strained layer superlattices (SLSs) in the InGaAlAs/GaAs and InAsSb/InSb material systems. The AFM results show quantitatively that over the temperature range from 380 to 545 C, graded in{sub x}Al{sub 1{minus}x}As(x = 0.05 {minus} 0.32) buffer layers grown at high temperatures ({approximately}520 C), and graded In{sub x}Ga{sub 1{minus}x}As (x = 0.05 {minus} 0.33) buffer layers and In{sub 0.4}Ga{sub 0.6}As/In{sub 0.26}Al{sub 0.35}Ga{sub 0.39}As SLSs grown at low temperatures ({approximately}400 C) have the lowest RMS roughness. Also, for SLSs InAs{sub 0.21}Sb{sub 0.79}/InSb, undoped layers grown at 470 C were smoother than undoped layers grown at 420 C and Be-doped layers grown at 470 C. These results illustrate the role of surface tension in the growth of strained layer materials near the melting temperature of the InAs{sub x}Sb{sub {minus}x}/InSb superlattice. Nomarski interference and transmission electron microscopies, IR photoluminescence, x-ray diffraction, and photocurrent spectroscopy were also used to evaluate the relative quality of the material but usually, the results were not conclusive.

  16. An Investigation into the Admittance of MIS-Structures Based on MBE HgCdTe with Quantum Wells

    NASA Astrophysics Data System (ADS)

    Dzyadukh, S. M.; Voitsekhovskii, A. V.; Nesmelov, S. N.; Dvoretskii, S. A.; N. Mikhailov, N.; Gorn, D. I.

    2013-12-01

    The results of investigations into the complex admittance of the MIS-structures based on heteroepitaxial MBE Hg1- x Cd x Te with quantum wells (QW) in the test-signal frequency range 1 kHz - 2 МHz at temperatures 8-300 K are reported. The thickness of single HgTe QWs was 5.6 and 7.1 nm, the content in the 35-nm thick barrier layers - 0.65 and 0.62, respectively.

  17. Multi-source MBE with high-precision rate control system as a synthesis method sui generis for multi-cation metal oxides

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hideki; Krockenberger, Yoshiharu; Naito, Michio

    2013-09-01

    Molecular beam epitaxy (MBE) has been an excellent tool to design artificial heterostructures in the research field of semiconductors by means of an alternate stacking of existing lattices. This article describes further capabilities of MBE as a synthesis tool sui generis, especially for multi-cation oxides, due to low-temperature reaction and the pseudomorphic stabilization effect by epitaxy. Single-crystalline Sr0.9La0.1CuO2 films exhibiting metallic conduction and superconductivity are successfully prepared by MBE. A new phase, T*-La2CuO4, is also stabilized on a DyScO3 substrate. Methods of high-precision rate control of each constituent element, which is prerequisite for a reproducible growth of the multi-cation oxide films, are also discussed.

  18. Self-regulating MBE growth of stoichiometric BaSnO3 films via reactive radical mechanism

    NASA Astrophysics Data System (ADS)

    Prakash, Abhinav; Dewey, John; Yun, Hwanhui; Jeong, Jong Seok; Mkhoyan, K. Andre; Jalan, Bharat

    Growth of thin films comprising of element with low oxidation potential such as Sn often requires reactive oxidants such as ozone or high-pressure oxygen plasma. By utilizing the chemistry of highly reactive radical of Sn, we will present on the growth of phase-pure, epitaxial BaSnO3 films using a hybrid molecular beam epitaxy (MBE) approach with scalable growth rates. The notable finding was that Sn radicals are very reactive to yield phase-pure BaSnO3 films even in molecular oxygen. In this approach, we use hexamethylditin (HMDT) as a tin source, a solid effusion cell for Ba and either molecular oxygen or an rf oxygen plasma source. Phase-pure BaSnO3 films were grown at 900 0C, and oxygen pressure of 5x10-6 Torr as a function Sn:Ba ratio. In-situ time-dependent RHEED intensity oscillations were observed establishing a layer-by-layer growth mode and a critical thickness of ~1 nm for strain relaxation. Rutherford backscattering spectrometry and lattice constant determined using high-resolution X-ray diffraction was used to optimize cation stoichiometry. ``MBE growth window'' was identified where films show bulk-like lattice parameter (4.116 Å) over a wide-range of cation flux ratios. A correlation between RHEED patterns, stoichiometry, and surface morphology was established This work is supported primarily by NSF (DMR-1410888).

  19. Si-doped AlGaAs/GaAs(6 3 1)A heterostructures grown by MBE as a function of the As-pressure

    NASA Astrophysics Data System (ADS)

    Méndez-García, Víctor-Hugo; Shimomura, S.; Gorbatchev, A. Yu.; Cruz-Hernández, E.; Vázquez-Cortés, D.

    2015-09-01

    The effects of doping with silicon (Si) AlGaAs layers grown by molecular beam epitaxy on GaAs (6 3 1)-oriented substrates as a function of the arsenic pressure (PAs) is presented and compared with layers grown on (1 0 0) oriented substrates. The surface texture of the AlGaAs (6 3 1) films is composed by nanogrooves, whose dimensions depend on PAs. On the contrary, the MBE growth on the (1 0 0) plane resulted on rough surfaces, without evidence of formation of terraces. Mobility and carrier density of AlGaAs:Si layers grown on substrates (6 3 1) were studied as a function of PAs. The doping type conversion from p-type to n-type as a function of the As pressure is corroborated for high index samples. All the films grown on (1 0 0) exhibited silicon n-type doping. These observations were related with the amphotericity of Si, where it acts as a donor impurity occupying Al or Ga-sites or as an acceptor when it takes an As-site, depending on the competition that the Si atoms encounters with As for any of these sites. The acceptor and donor lines close to the AlGaAs transition observed by photoluminescence spectroscopy (PL) were affected by the incorporation of Si. When increasing PAs the energy of the main PL peak is redshifted for n-type AlGaAs layers, but it is shifted back towards high energy once the conduction type conversion takes place. X-ray diffraction patterns revealed high crystalline quality for samples grown at the highest PAs.

  20. Anomalous elongation of c-axis of GaN on Al2O3 grown by MBE using NH3-cluster ions

    NASA Astrophysics Data System (ADS)

    Ichinohe, Yoshihiro; Imai, Kazuaki; Suzuki, Kazuhiko; Saito, Hiroshi

    2016-02-01

    GaN thin films were grown on Al2O3 (0001) by MBE using NH3-clusters either ionized with the energy of 4-7 eV/molecule (ionized Cluster Beam, i-CB) or un-ionized with the energy of about 0.1 eV/molecule (neutral Cluster Beam, n-CB) at growth temperatures ranging from 390 to 960 °C. The c-axis is extremely elongated but the a-axis is shrunken at the initial growth stage (up to the film thickness of about 10 nm) in GaN grown by the mixture of n- and i-CB under N-rich condition. The films thicker than 30 nm have the relaxed a- and c-axis lengths close to the unstrained values and obey the Poisson relation. GaN grown by i-CB under Ga-rich condition have the relaxed lattice constants obeying the Poisson relation for the film as thin as 6 nm. In GaN grown by the cluster beam (CB) which is not ionized intentionally, both a- and c-axis lengths are almost independent of the film thickness, having nearly the same values as those of the unstrained samples. These characteristics can be ascribed to the nature of interface between the nitrided Al2O3 substrate and epilayer. It is concluded that the films grown by i-CB bond firmly to underlay AlN than the films by n-CB and CB.

  1. 40 CFR 33.210 - Does an entity certified as an MBE or WBE by EPA need to keep EPA informed of any changes which...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Does an entity certified as an MBE or....210 Section 33.210 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE PARTICIPATION BY DISADVANTAGED BUSINESS ENTERPRISES IN UNITED STATES ENVIRONMENTAL...

  2. Molecular beam epitaxy (MBE) growth of rare earth doped gallium nitride for laser diode application

    NASA Astrophysics Data System (ADS)

    Park, Jeongho

    The goal of this dissertation is to demonstrate the visible laser emission from rare earth doped GaN grown on sapphire and silicon substrate. The research presented in this dissertation focused on exploration of RE's physics and laser characteristics and investigating site selective laser emission. In this study, the first visible (red) lasing emission from Eu-doped GaN thin films grown on sapphire substrates was demonstrated. The edge emission fulfills the requirements of stimulated emission properties: super-linear characteristic, spectrum line narrowing, polarization effect, lifetime reduction, and longitudinal modes in a Fabry-Perot cavity. The GaN:Eu active layer has low threshold (˜10kW/cm2) for the onset of lasing. The optical gain and loss are of the order of 50 and 20cm-1, respectively. Growth conditions are investigated for gain enhancement and loss reduction. To obtain the high gain and low loss active layer, N-rich growth conditions are required. Channel waveguide cavities result in 5x increases in gain value compared to planar waveguides. To utilize the performance and flexibility of silicon microelectronics, we used silicon (111) substrate, which incorporated several AlGaN and AIN thin films as buffer, strain compensation and bottom optical cladding layers. With this substrate, we developed the laser structure emitting visible wavelength. We have utilized Eu-doped GaN for the active medium within a structure consisting of a top cladding AlGaN layers grown by MBE on a Si substrate. Stimulated emission (SE) was obtained at room temperature from Eu3+ at 620nm, with a threshold of ˜117kW/cm 2. Values of modal gain and loss of ˜100 and 46 cm-1 were measured. This demonstration indicates that utilizing rare earths a range of lasers on Si can be obtained, covering the UV, visible and IR regions, thus enabling a significant expansion of optoelectronic and microelectronic integration. The dependence of optical modal gain and loss on GaN:Eu growth

  3. X-ray Investigation of Ferromagnetic MnAs Thin Films Grown on GaAs(001) by MBE

    NASA Astrophysics Data System (ADS)

    Huang, S.; Ming, Z. H.; Soo, Y. L.; Kao, Y. H.; Tanaka, M.; Munekata, H.

    1996-03-01

    Quantitative characterization of the microstructures in epitaxial layers grown by MBE is essential for understanding the dynamical processes of epitaxy and surface morphology. In the present study, various x-ray techniques including grazing incidence x-ray scattering (GIXS), x-ray diffraction (XRD), and extended x-ray absorption fine structure (EXAFS) have been employed to investigate the microstructures of two MnAs thin films grown on GaAs(001) by using two different growth templates. The film structures are compared in terms of the interfacial roughness, lattice constants, epilayer thickness, local environment surrounding the Mn atoms, coordination number, and local disorder. These results provide quantitative evidence for the effects of template on the local structure and crystallinity of the MnAs films which can be correlated with the observed difference in their physical properties such as the easy magnetization direction, etc.. * Research is supported in part by DOE.

  4. Thermal Stability of Ge/GeSn Nanostructures Grown by MBE on (001) Si/Ge Virtual Wafers

    NASA Astrophysics Data System (ADS)

    Sadofyev, Yu. G.; Martovitsky, V. P.; Klekovkin, A. V.; Saraikin, V. V.; Vasil'evskii, I. S.

    A stack of five metastable 200-nm-thick elastically strained GeSn epitaxial layers separated by 20-nm-thick Ge spacers was grown on (001) Si/Ge virtual substrate by MBE. The molar fraction of Sn in different layers varied from 0.005 to 0.10, increasing with the layer distance from the Ge buffer. The phase separation of the GeSn alloy during postgrowth annealing takes place along with plastic relaxation. The phase separation begins well before the completion of the plastic relaxation process. The degree of phase separation at a given annealing temperature depends strongly on the Sn content in the GeSn alloy. The Sn released from the decomposed GeSn alloy predominantly accumulates as an amorphous layer on the surface of the sample.

  5. Laser-MBE of nickel nanowires using AAO template: a new active substrate of surface enhanced Raman scattering.

    PubMed

    Zhang, Lisheng; Fang, Yan; Zhang, Pengxiang

    2008-01-01

    The highly ordered anodic aluminum oxide (AAO) template was fabricated using aluminum anodizing in electrolytes with two-step method, which apertures were about 50-80nm. The nickel nanowires with about 40-70nm in diameter was prepared on the AAO template by laser-MBE (molecular beam epitaxy). And high quality Raman spectra of SudanII were obtained on the glass covered with the nickel nanowires. On the nickel nanowires there are both surface enhanced Raman scattering (SERS) and tip enhanced Raman scattering (TERS). The new observations not only enlarge the range of SERS applications, but also imply a possible new enhancement mechanism. Otherwise the Raman and SERS frequencies of SudanII molecule were calculated using, respectively, DFT and B3PW91. PMID:17627875

  6. Epitaxial metallic β-Nb2N films grown by MBE on hexagonal SiC substrates

    NASA Astrophysics Data System (ADS)

    Katzer, D. Scott; Nepal, Neeraj; Meyer, David J.; Downey, Brian P.; Wheeler, Virginia D.; Storm, David F.; Hardy, Matthew T.

    2015-08-01

    RF-plasma MBE was used to epitaxially grow 4- to 100-nm-thick metallic β-Nb2N thin films on hexagonal SiC substrates. When the N/Nb flux ratios are greater than one, the most critical parameter for high-quality β-Nb2N is the substrate temperature. The X-ray characterization of films grown between 775 and 850 °C demonstrates β-Nb2N phase formation. The (0002) and (21\\bar{3}1) X-ray diffraction measurements of a β-Nb2N film grown at 850 °C reveal a 0.68% lattice mismatch to the 6H-SiC substrate. This suggests that β-Nb2N can be used for high-quality metal/semiconductor heterostructures that cannot be fabricated at present.

  7. Polarized Raman spectroscopy of corrugated MBE grown GaAs (6¯3¯1¯) homoepitaxial films

    NASA Astrophysics Data System (ADS)

    Espinosa-Vega, L. I.; Rodriguez, A. G.; Cruz-Hernandez, E.; Martinez-Veliz, I.; Rojas-Ramirez, J.; Ramirez-Lopez, M.; Nieto-Navarro, J.; Lopez-Lopez, M.; Mendez-Garcia, V. H.

    2013-09-01

    In this work, we present a Raman scattering study of GaAs layers grown on (6¯3¯1¯)-oriented substrates by molecular beam epitaxy. A set of samples whose morphology sustained different corrugation order were grown by MBE by varying the growth parameters such as temperature and As/Ga flux ratio. We employed polarized Raman spectroscopy using the backscattering configurations Z(XX) Z¯, Z(XY) Z¯ and Z(YY)Z¯. According to the calculated dipole selection rules both TO and LO phonons are allowed for backscattering from a perfect GaAs (6¯3¯1¯) crystal, but with the intensity of the TO phonon much larger than that of the LO phonon. However, it is found that the selection rules differ for corrugated samples. Besides, the TO/LO phonon resonances intensity ratio and the LO peak asymmetry depend on the corrugation order of the samples.

  8. Nanoscale Probing of Local Electrical Characteristics on MBE-Grown Bi₂Te₃ Surfaces under Ambient Conditions.

    PubMed

    Macedo, Rita J; Harrison, Sara E; Dorofeeva, Tatiana S; Harris, James S; Kiehl, Richard A

    2015-07-01

    The local electrical characteristics on the surface of MBE-grown Bi2Te3 are probed under ambient conditions by conductive atomic force microscopy. Nanoscale mapping reveals a 10-100× enhancement in current at step-edges compared to that on terraces. Analysis of the local current-voltage characteristics indicates that the transport mechanism is similar for step-edges and terraces. Comparison of the results with those for control samples shows that the current enhancement is not a measurement artifact but instead is due to local differences in electronic properties. The likelihood of various possible mechanisms is discussed. The absence of enhancement at the step-edges for graphite terraces is consistent with the intriguing possibility that spin-orbit coupling and topological effects play a significant role in the step-edge current enhancement in Bi2Te3. PMID:26030139

  9. Possibilities for LWIR detectors using MBE-grown Si(/Si(1-x)Ge(x) structures

    NASA Technical Reports Server (NTRS)

    Hauenstein, Robert J.; Miles, Richard H.; Young, Mary H.

    1990-01-01

    Traditionally, long wavelength infrared (LWIR) detection in Si-based structures has involved either extrinsic Si or Si/metal Schottky barrier devices. Molecular beam epitaxially (MBE) grown Si and Si/Si(1-x)Ge(x) heterostructures offer new possibilities for LWIR detection, including sensors based on intersubband transitions as well as improved conventional devices. The improvement in doping profile control of MBE in comparison with conventional chemical vapor deposited (CVD) Si films has resulted in the successful growth of extrinsic Si:Ga, blocked impurity-band conduction detectors. These structures exhibit a highly abrupt step change in dopant profile between detecting and blocking layers which is extremely difficult or impossible to achieve through conventional epitaxial growth techniques. Through alloying Si with Ge, Schottky barrier infrared detectors are possible, with barrier height values between those involving pure Si or Ge semiconducting materials alone. For both n-type and p-type structures, strain effects can split the band edges, thereby splitting the Schottky threshold and altering the spectral response. Measurements of photoresponse of n-type Au/Si(1-x)Ge(x) Schottky barriers demonstrate this effect. For intersubband multiquntum well (MQW) LWIR detection, Si(1-x)Ge(x)/Si detectors grown on Si substrates promise comparable absorption coefficients to that of the Ga(Al)As system while in addition offering the fundamental advantage of response to normally incident light as well as the practical advantage of Si-compatibility. Researchers grew Si(1-x)Ge(x)/Si MQW structures aimed at sensitivity to IR in the 8 to 12 micron region and longer, guided by recent theoretical work. Preliminary measurements of n- and p-type Si(1-x)Ge(x)/Si MQW structures are given.

  10. High Quality GaAs Growth by MBE on Si Using GeSi Buffers and Prospects for Space Photovoltaics

    NASA Technical Reports Server (NTRS)

    Carlin, J. A.; Ringel, S. A.; Fitzgerald, E. A.; Bulsara, M.

    2005-01-01

    III-V solar cells on Si substrates are of interest for space photovoltaics since this would combine high performance space cells with a strong, lightweight and inexpensive substrate. However, the primary obstacles blocking III-V/Si cells from achieving high performance to date have been fundamental materials incompatabilities, namely the 4% lattice mismatch between GaAs and Si, and the large mismatch in thermal expansion coefficient. In this paper, we report on the molecular beam epitaxial (MBE) growth and properties of GaAs layers and single junction GaAs cells on Si wafers which utilize compositionally graded GeSi Intermediate buffers grown by ultra-high vacuum chemical vapor deposition (UHVCVD) to mitigate the large lattice mismatch between GaAs and Si. Ga As cell structures were found to incorporate a threading dislocation density of 0.9-1.5 x 10 (exp 6) per square centimeter, identical to the underlying relaxed Ge cap of the graded buffer, via a combination of transmission electron microscopy, electron beam induced current, and etch pit density measurements. AlGaAs/GaAs double heterostructures wre grown on the GeSi/Si substrates for time-resolved photoluminescence measurements, which revealed a bulk GaAs minority carrier lifetime in excess of 10 ns, the highest lifetime ever reported for GaAs on Si. A series of growth were performed to ass3ss the impact of a GaAs buffer to a thickness of only 0.1 micrometer. Secondary ion mass spectroscopy studies revealed that there is negligible cross diffusion of Ga, As and Ge at he III-V/Ge interface, identical to our earlier findings for GaAs grown on Ge wafers using MBE. This indicates that there is no need for a buffer to "bury" regions of high autodopjing,a nd that either pn or np configuration cells are easily accomodated by these substrates. Preliminary diodes and single junction Al Ga As heteroface cells were grown and fabricated on the Ge/GeSi/Si substrates for the first time. Diodes fabricated on GaAs, Ge and Ge

  11. A new approach to epitaxially grow high-quality GaN films on Si substrates: the combination of MBE and PLD

    PubMed Central

    Wang, Wenliang; Wang, Haiyan; Yang, Weijia; Zhu, Yunnong; Li, Guoqiang

    2016-01-01

    High-quality GaN epitaxial films have been grown on Si substrates with Al buffer layer by the combination of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) technologies. MBE is used to grow Al buffer layer at first, and then PLD is deployed to grow GaN epitaxial films on the Al buffer layer. The surface morphology, crystalline quality, and interfacial property of as-grown GaN epitaxial films on Si substrates are studied systematically. The as-grown ~300 nm-thick GaN epitaxial films grown at 850 °C with ~30 nm-thick Al buffer layer on Si substrates show high crystalline quality with the full-width at half-maximum (FWHM) for GaN(0002) and GaN(102) X-ray rocking curves of 0.45° and 0.61°, respectively; very flat GaN surface with the root-mean-square surface roughness of 2.5 nm; as well as the sharp and abrupt GaN/AlGaN/Al/Si hetero-interfaces. Furthermore, the corresponding growth mechanism of GaN epitaxial films grown on Si substrates with Al buffer layer by the combination of MBE and PLD is hence studied in depth. This work provides a novel and simple approach for the epitaxial growth of high-quality GaN epitaxial films on Si substrates. PMID:27101930

  12. A new approach to epitaxially grow high-quality GaN films on Si substrates: the combination of MBE and PLD

    NASA Astrophysics Data System (ADS)

    Wang, Wenliang; Wang, Haiyan; Yang, Weijia; Zhu, Yunnong; Li, Guoqiang

    2016-04-01

    High-quality GaN epitaxial films have been grown on Si substrates with Al buffer layer by the combination of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) technologies. MBE is used to grow Al buffer layer at first, and then PLD is deployed to grow GaN epitaxial films on the Al buffer layer. The surface morphology, crystalline quality, and interfacial property of as-grown GaN epitaxial films on Si substrates are studied systematically. The as-grown ~300 nm-thick GaN epitaxial films grown at 850 °C with ~30 nm-thick Al buffer layer on Si substrates show high crystalline quality with the full-width at half-maximum (FWHM) for GaN(0002) and GaN(102) X-ray rocking curves of 0.45° and 0.61°, respectively; very flat GaN surface with the root-mean-square surface roughness of 2.5 nm as well as the sharp and abrupt GaN/AlGaN/Al/Si hetero-interfaces. Furthermore, the corresponding growth mechanism of GaN epitaxial films grown on Si substrates with Al buffer layer by the combination of MBE and PLD is hence studied in depth. This work provides a novel and simple approach for the epitaxial growth of high-quality GaN epitaxial films on Si substrates.

  13. A new approach to epitaxially grow high-quality GaN films on Si substrates: the combination of MBE and PLD.

    PubMed

    Wang, Wenliang; Wang, Haiyan; Yang, Weijia; Zhu, Yunnong; Li, Guoqiang

    2016-01-01

    High-quality GaN epitaxial films have been grown on Si substrates with Al buffer layer by the combination of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) technologies. MBE is used to grow Al buffer layer at first, and then PLD is deployed to grow GaN epitaxial films on the Al buffer layer. The surface morphology, crystalline quality, and interfacial property of as-grown GaN epitaxial films on Si substrates are studied systematically. The as-grown ~300 nm-thick GaN epitaxial films grown at 850 °C with ~30 nm-thick Al buffer layer on Si substrates show high crystalline quality with the full-width at half-maximum (FWHM) for GaN(0002) and GaN(102) X-ray rocking curves of 0.45° and 0.61°, respectively; very flat GaN surface with the root-mean-square surface roughness of 2.5 nm; as well as the sharp and abrupt GaN/AlGaN/Al/Si hetero-interfaces. Furthermore, the corresponding growth mechanism of GaN epitaxial films grown on Si substrates with Al buffer layer by the combination of MBE and PLD is hence studied in depth. This work provides a novel and simple approach for the epitaxial growth of high-quality GaN epitaxial films on Si substrates. PMID:27101930

  14. Near-Infrared Absorption in Lattice-Matched AlInN/GaN and Strained AlGaN/GaN Heterostructures Grown by MBE on Low-Defect GaN Substrates

    NASA Astrophysics Data System (ADS)

    Edmunds, C.; Tang, L.; Li, D.; Cervantes, M.; Gardner, G.; Paskova, T.; Manfra, M. J.; Malis, O.

    2012-05-01

    We have investigated near-infrared absorption and photocurrent in lattice-matched AlInN/GaN and strained AlGaN/GaN heterostructures grown by molecular-beam epitaxy (MBE) on low-defect GaN substrates for infrared device applications. The AlGaN/GaN heterostructures were grown under Ga-rich conditions at 745°C. Material characterization via atomic force microscopy and high-resolution x-ray diffraction indicates that the AlGaN/GaN heterostructures have smooth and well-defined interfaces. A minimum full-width at half-maximum of 92 meV was obtained for the width of the intersubband absorption peak at 675 meV of a 13.7 Å GaN/27.5 Å Al0.47Ga0.53N superlattice. The variation of the intersubband absorption energy across a 1 cm × 1 cm wafer was ±1%. An AlGaN/GaN-based electromodulated absorption device and a quantum well infrared detector were also fabricated. Using electromodulated absorption spectroscopy, the full-width at half-maximum of the absorption peak was reduced by 33% compared with the direct absorption measurement. This demonstrates the suitability of the electromodulated absorption technique for determining the intrinsic width of intersubband transitions. The detector displayed a peak responsivity of 195 μA/W at 614 meV (2.02 μm) without bias. Optimal MBE growth conditions for lattice-matched AlInN on low-defect GaN substrates were also studied as a function of total metal flux and growth temperature. A maximum growth rate of 3.8 nm/min was achieved while maintaining a high level of material quality. Intersubband absorption in AlInN/GaN superlattices was observed at 430 meV with full-width at half-maximum of 142 meV. Theoretical calculations of the intersubband absorption energies were found to be in agreement with the experimental results for both AlGaN/GaN and AlInN/GaN heterostructures.

  15. Surface sulfurization on MBE-grown Cu(In1-x,Gax)Se2 thin films and devices

    NASA Astrophysics Data System (ADS)

    Khatri, Ishwor; Matsuyama, Isamu; Yamaguchi, Hiroshi; Fukai, Hirofumi; Nakada, Tokio

    2015-08-01

    Molecular beam epitaxy (MBE) grown Cu(In1-x,Gax)Se2 (CIGS) thin films were sulfurized at temperatures of 450-550 °C for 30 min in a 10% H2S-N2 mixture gas. The micro-roughness together with the S diffusion in the CIGS surfaces increased with increasing sulfurization temperature. Both near-band-edge PL intensity and decay time of the CIGS absorber layer enhanced after sulfurization. PL sub-peak around 80 meV below the main peak almost disappeared after sulfurization above 500 °C, which is expected due to the occupation of Se vacancies (Vse) with S. The open-circuit voltage (Voc), hence conversion efficiency, improved after sulfurization. The photovoltaic performance of the solar cells was consistent with PL intensity. Moreover, it is found for the first time from the SIMS analysis that the Cu atoms were depleted at the surface of CIGS layer after sulfurization, which could result in the improved Voc.

  16. Vanadium dioxide thin films prepared on silicon by low temperature MBE growth and ex-situ annealing

    NASA Astrophysics Data System (ADS)

    Homm, Pia; van Bilzen, Bart; Menghini, Mariela; Locquet, Jean-Pierre; Ivanova, Todora; Sanchez, Luis; Sanchis, Pablo

    Vanadium dioxide (VO2) is a material that shows an insulator to metal transition (IMT) near room temperature. This property can be exploited for applications in field effect devices, electro-optical switches and nonlinear circuit components. We have prepared VO2 thin films on silicon wafers by combining a low temperature MBE growth with an ex-situ annealing at high temperature. We investigated the structural, electrical and optical characteristics of films with thicknesses ranging from 10 to 100 nm. We have also studied the influence of the substrate cleaning. The films grown with our method are polycrystalline with a preferred orientation in the (011) direction of the monoclinic phase. For the films produced on silicon with a native oxide, an IMT at around 75 °C is observed. The magnitude of the resistance change across the IMT decreases with thickness while the refractive index at room temperature corresponds with values reported in the literature for thin films. The successful growth of VO2 films on silicon with good electrical and optical properties is an important step towards the integration of VO2 in novel devices. The authors acknowledge financial support from the FWO project G052010N10 and EU-FP7 SITOGA project. PH acknowledges support from Becas Chile - CONICYT.

  17. Microstructures of InN film on 4H-SiC (0001) substrate grown by RF-MBE

    NASA Astrophysics Data System (ADS)

    Jantawongrit, P.; Sanorpim, S.; Yaguchi, H.; Orihara, M.; Limsuwan, P.

    2015-08-01

    InN film was grown on 4H-SiC (0001) substrate by RF plasma-assisted molecular beam epitaxy (RF-MBE). Prior to the growth of InN film, an InN buffer layer with a thickness of ∼5.5 nm was grown on the substrate. Surface morphology, microstructure and structural quality of InN film were investigated. Micro-structural defects, such as stacking faults and anti-phase domain in InN film were carefully investigated using transmission electron microscopy (TEM). The results show that a high density of line contrasts, parallel to the growth direction (c-axis), was clearly observed in the grown InN film. Dark field TEM images recorded with diffraction vectors g=11\\bar{2}0 and g = 0002 revealed that such line contrasts evolved from a coalescence of the adjacent misoriented islands during the initial stage of the InN nucleation on the substrate surface. This InN nucleation also led to a generation of anti-phase domains. Project supported by the Thailand Center of Excellence in Physics (ThEP) and the King Mongkut's University of Technology Thonburi under The National Research University Project. One of the authors (S. Sanorpim) was supported by the National Research Council of Thailand (NRCT) and the Thai Government Stimulus Package 2 (TKK2555), under the Project for Establishment of Comprehensive Center for Innovative Food, Health Products and Agriculture.

  18. In Memory of Dorothy Heathcote, MBE (29 August 1926 to 8 October 2011)

    ERIC Educational Resources Information Center

    Saxton, Juliana; Miller, Carole

    2012-01-01

    In this article, the authors aim to provide a multifaceted lens on to Dorothy Heathcote's enormous influence on the field of drama education. They choose to order the reminiscences historically, focusing on Heathcote's consistency of passion and purpose. The anecdotes, lesson descriptions, and reminiscences capture her voice, her energy, and her…

  19. Surface defect states in MBE-grown CdTe layers

    SciTech Connect

    Olender, Karolina; Wosinski, Tadeusz; Fronc, Krzysztof; Tkaczyk, Zbigniew; Chusnutdinow, Sergij; Karczewski, Grzegorz

    2014-02-21

    Semiconductor surface plays an important role in the technology of semiconductor devices. In the present work we report results of our deep-level transient spectroscopy (DLTS) investigations of surface defect states in nitrogen doped p-type CdTe layers grown by the molecular-beam epitaxy technique. We observed a deep-level trap associated with surface states, with the activation energy for hole emission of 0.33 eV. DLTS peak position in the spectra for this trap, and its ionization energy, strongly depend on the electric field. Our measurements allow to determine a mechanism responsible for the enhancement of hole emission rate from the traps as the phonon-assisted tunnel effect. Density of surface defect states significantly decreased as a result of passivation in ammonium sulfide. Capacitance-voltage measurements confirmed the results obtained by the DLTS technique.

  20. Optical properties of ZnxMg1-xSe/GaAs heterojunctions grown by MBE

    NASA Astrophysics Data System (ADS)

    Bala, Waclaw; Glowacki, Grzegorz; Gapinski, Adam

    1997-06-01

    This works focuses on the study of optical properties of ZnxMg1-xSe epilayers grown by molecular beam epitaxy on n-type (001) GaAs substrates. Luminescence, reflectivity and Raman spectroscopy are studied. Photoluminescence spectra of the samples are dominated by blue emission bands, which can be associated with radiative recombination of free excitons. The reflectivity spectra were used to investigate the refractive index value and the thickness of the layers. Moreover the temperature dependence of the band-gap energy of ZnxMg1-xSe epilayers was determined. Using Raman spectroscopy we can obtain information about two kinds of longitudinal optical phonon modes observed at room temperature, whose frequencies and intensities depend characteristically on Mg content.

  1. ZnMgS-based solar-blind UV photodetectors grown by MBE

    NASA Astrophysics Data System (ADS)

    Sou, I. K.; Wu, Marcus C. W.; Wong, K. S.; Wong, G. K. L.

    2001-07-01

    Molecular beam epitaxial growth of Zn 1- xMg xS alloy thin films on GaP (1 0 0) substrates is reported. In situ reflection high energy electron diffraction (RHEED) studies show that the alloys can be grown with stable zinc-blende structure up to x around 30%. For x>30%, a phase transition will occur at a critical thickness which is sensitively dependent on the composition x. Several Schottky barrier photodetectors using Zn 1- xMg xS layer, with thickness less than the critical thickness, as active layer were fabricated. High ultra-violet responsivity and excellent visible rejection are achieved. The response curve of the Zn 0.43Mg 0.57S device offers a long wavelength cut-off at 295 nm and closely matches the erythemal action spectrum that describes human skin sensitivity to UV radiation.

  2. Selectively doped GaAs/N-Al(0.3)Ga(0.7)As heterostructures grown by gas-source MBE

    NASA Astrophysics Data System (ADS)

    Ando, Hideyasu; Kondo, Kazuhiro; Ishikawa, Hideaki; Sasa, Shigehiko; Inata, Tsuguo

    1988-05-01

    Selectively doped GaAs/N-Al(0.3)Ga(0.7)As heterostructures with a 6 nm spacer layer have been grown for the first time by gas-source MBE using triethylgallium and triethylaluminum as group III sources, and metallic arsenic. A reasonably high two-dimensional electron gas (2DEG) mobility of 48,000 sq cm / Vs (77 K) with a sheet electron concentration of 6.8 x 10 to the 11th/sq cm was obtained at a substrate temperature of 580 C and an arsenic pressure of 0.00011.

  3. Properties of MBE-grown NbO2 thin films

    NASA Astrophysics Data System (ADS)

    Demkov, Alex; O'Hara, Andy; Posadas, Agham

    2014-03-01

    Niobium dioxide or NbO2 a sister compound of the more celebrated VO2, belongs to the class of transition metal oxides that undergo a temperature-driven metal-to-insulator transition. Using density functional theory, we explore the electronic properties of both the high-temperature metallic rutile and the low-temperature insulating distorted rutile phases. We investigate the nature of the transition and predict a large carrier concentration change even at the high transition temperature of 1080 K. We also grew thin NbO2 films on LSAT(111) single crystal substrates using molecular beam epitaxy. The films show very good crystallinity with a single out-of-plane orientation by x-ray diffraction, and exhibit a smooth surface with the presence of three epitaxial domains as observed by reflection high energy electron diffraction. The NbO2 stoichiometry is confirmed by x-ray photoemission measurements of the Nb 3d core level as well as the valence band.

  4. Surface reconstructions and transport of epitaxial PtLuSb (001) thin films grown by MBE

    NASA Astrophysics Data System (ADS)

    Patel, Sahil J.; Logan, John A.; Harrington, Sean D.; Schultz, Brian D.; Palmstrøm, Chris J.

    2016-02-01

    This work presents the surface reconstructions and transport properties of the topological insulator PtLuSb grown on Al0.1In0.9Sb/GaAs (001). Two stable surface reconstructions, (1×3) and c(2×2), were observed on PtLuSb (001) surfaces. Antimony-dimerization was determined to be the nature of the (1×3) surface reconstruction as evidenced by chemical binding energy shifts in the antimony 4d core-level for surface bonding components. The two surface reconstructions were studied as a function of Sb4 overpressure and substrate temperature to create a reconstruction phase diagram. From this reconstruction phase diagram, a growth window from 320 °C to 380 °C using an antimony overpressure was identified. Within this window, the highest quality films were grown at a growth temperature of 380 °C. These films exhibited lower p-type carrier concentrations as well as relatively high hole mobilities.

  5. Comparison of low temperature photoluminescence of bulk MBE (Molecular Beam Epitaxy) grown AlGaAs and GaAs using a graphite generated dimer versus a standard tetramer arsenic group-V source

    SciTech Connect

    Brennan, T.M.; Hammons, B.E.; Smith, M.C.; Jones, E.D.

    1987-01-01

    The carbon concentrations in GaAs and AlGaAs grown by Molecular Beam Epitaxy (MBE) have been studied when a graphite generated dimeric arsenic species and a standard tetramer arsenic species are used as the group-V source. Photoluminescence and Van der Pauw-Hall measurements have been made to examine the material quality in reference to which arsenic species is used for film growth. Results indicate that a graphite crucible arrangement for the thermal cracking of As/sub 4/ produces significant carbon contamination and is unacceptable for the MBE growth of GaAs and AlGaAs. 15 refs., 3 figs.

  6. MBE (Molecular Beam Epitaxial) growth characterization and electronic device processing of HgCdTe, HgZnTe related heterojunctions and HgCdTe-CdTe superlattices

    NASA Astrophysics Data System (ADS)

    Faurie, Jean-Pierre

    1987-06-01

    As the MBE growth technique has continued to improve for Hg(1-x)Cd(x)Te films, the prospects for films of larger area have begun to be explored. These larger area films are important for imaging arrays and will be especially vital in the future for the efficient production of Hg(1-x)Cd(x)Te material. The growth of MBE of uniform Hg(1-x)Cd(x)Te epilayer on a large substrate is very difficult to achieve because of the non-uniform distribution of the fluxes and on the non-uniform temperature of the substrate.

  7. Recent Progress in MBE Growth of CdTe and HgCdTe on (211)B GaAs Substrates

    NASA Astrophysics Data System (ADS)

    Carmody, M.; Yulius, A.; Edwall, D.; Lee, D.; Piquette, E.; Jacobs, R.; Benson, D.; Stoltz, A.; Markunas, J.; Almeida, A.; Arias, J.

    2012-10-01

    Alternate substrates for molecular beam epitaxy growth of HgCdTe including Si, Ge, and GaAs have been under development for more than a decade. MBE growth of HgCdTe on GaAs substrates was pioneered by Teledyne Imaging Sensors (TIS) in the 1980s. However, recent improvements in the layer crystal quality including improvements in both the CdTe buffer layer and the HgCdTe layer growth have resulted in GaAs emerging as a strong candidate for replacement of bulk CdZnTe substrates for certain infrared imaging applications. In this paper the current state of the art in CdTe and HgCdTe MBE growth on (211)B GaAs and (211) Si at TIS is reviewed. Recent improvements in the CdTe buffer layer quality (double crystal rocking curve full-width at half-maximum ≈ 30 arcsec) with HgCdTe dislocation densities of ≤106 cm-2 are discussed and comparisons are made with historical HgCdTe on bulk CdZnTe and alternate substrate data at TIS. Material properties including the HgCdTe majority carrier mobility and dislocation density are presented as a function of the CdTe buffer layer quality.

  8. A low-temperature growth process of GaAs by electron-cyclotron-resonance plasma-excited molecular-beam-epitaxy (ECR-MBE)

    NASA Astrophysics Data System (ADS)

    Kondo, Naoto; Nanishi, Yasushi

    1988-09-01

    Taking advantage of plasma excitation, surface cleaning and growth process are realized at low temperatures by electron-cyclotron-resonance (ECR) plasma-excited molecular-beam-epitaxy (MBE). Prior to growth, substrates are cleaned by exposure to hydrogen plasma at temperatures ranging from 300 to 550°C. Arsine gas is introduced and cracked in an ECR plasma generation chamber. Gallium is supplied either as trimethylgallium (TMG) or as metallic Ga. Epitaxial films are successfully grown at substrate temperatures low as 430°C for the TMG-arsine system and 350°C for the metallic Ga-arsine system. The growth rate for the TMG-arsine system is found to be governed by a balance between TMG decomposition and surface atom desorption. By contrast, the metallic Ga-arsine system is only governed by the desorption process. Exposure to plasma is found to promote desorption of atoms migrating on the substrate surface. The interface between the substrate and the epitaxial layer produced by the ECR-MBE process is found to be clean without piling up of impurity.

  9. Investigation of p-side contact layers for II-VI compound semiconductor optical devices fabricated on InP substrates by MBE

    NASA Astrophysics Data System (ADS)

    Takamatsu, Shingo; Nomura, Ichirou; Shiraishi, Tomohiro; Kishino, Katsumi

    2015-09-01

    N-doped p-type ZnTe and ZnSeTe contact layers were investigated to evaluate which is more suitable for use in II-VI compound semiconductor optical devices on InP substrates. Contact resistances (Rc) between the contact layers and several electrode materials (Pd/Pt/Au, Pd/Au, and Au) were measured by the circular transmission line model (c-TLM) method using p-n diode samples grown on InP substrates by molecular beam epitaxy (MBE). The lowest Rc (6.5×10-5 Ω cm2) was obtained in the case of the ZnTe contact and Pd/Pt/Au electrode combination, which proves that the combination is suitable for obtaining low Rc. Yellow light-emitting diode devices with a ZnTe and ZnSeTe p-contact layer were fabricated by MBE to investigate the effect of different contact layers. The devices were characterized under direct current injections at room temperature. Yellow emission at around 600 nm was observed for each device. Higher emission intensity and lower slope resistance were obtained for the device with the ZnTe contact layer and Pd/Pt/Au electrode compared with other devices. These device performances are ascribed to the low Rc of the ZnTe contact and Pd/Pt/Au electrode combination.

  10. Convergence of the Many-Body Expansion for Energy and Forces for Classical Polarizable Models in the Condensed Phase.

    PubMed

    Demerdash, Omar; Head-Gordon, Teresa

    2016-08-01

    We analyze convergence of energies and forces for the AMOEBA classical polarizable model when evaluated as a many-body expansion (MBE) against the corresponding N-body parent potential in the context of a condensed-phase water simulation. This is in contrast to most MBE formulations based on quantum mechanics, which focus only on convergence of energies for gas-phase clusters. Using a single water molecule as a definition of a body, we find that truncation of the MBE at third order, 3-AMOEBA, captures direct polarization exactly and yields apparent good convergence of the mutual polarization energy. However, it renders large errors in the magnitude of polarization forces and requires at least fourth-order terms in the MBE to converge toward the parent potential gradient values. We can improve the convergence of polarization forces for 3-AMOEBA by embedding the polarization response of dimers and trimers within a complete representation of the fixed electrostatics of the entire system. We show that the electrostatic embedding formalism helps identify the specific configurations involving linear hydrogen-bonding arrangements that are poorly convergent at the 3-body level. By extending the definition of a body to be a large water cluster, we can reduce errors in forces to yield an approximate polarization model that is up to 10 times faster than the parent potential. The 3-AMOEBA model offers new ways to investigate how the properties of bulk water depend on the degree of connectivity in the liquid. PMID:27405002

  11. Growth and magnetic properties of zb-type MnAs films on GaAs substrates by high-temperature MBE

    NASA Astrophysics Data System (ADS)

    Kubo, K.; Kato, Y.; Kanai, K.; Ohta, J.; Fujioka, H.; Oshima, M.

    2008-10-01

    We have grown MnAs films on GaAs(1 1 1)B substrates by high-temperature molecular beam epitaxy (MBE) and have investigated their crystal structures and magnetic properties. X-ray diffraction (XRD) and grazing incidence X-ray diffraction (GIXD) results showed that two kinds of zb-type MnAs films with lattice constants of 5.73 and 5.96 Å were grown. The zb-type MnAs films show higher Curie temperature than 350 K and larger magnetization than the reported zb-type MnAs. At the initial stage of MnAs growth, Ga 1-xMn xAs was grown and this Ga 1-xMn xAs layer might play an important role of a buffer layer to enable the zb-MnAs growth.

  12. Effects of buffer layer and back-surface field on MBE-grown InGaAsP/InGaAs solar cells

    NASA Astrophysics Data System (ADS)

    Wu, Yuanyuan; Ji, Lian; Dai, Pai; Tan, Ming; Lu, Shulong; Yang, Hui

    2016-02-01

    Solid-state molecular beam epitaxy (MBE)-grown InGaAsP/InGaAs dual-junction solar cells on InP substrates are reported. An efficiency of 10.6% under 1-sun AM1.5 global light intensity is realized for the dual-junction solar cell, while the efficiencies of 16.4 and 12.3% are reached for the top InGaAsP and bottom InGaAs cells, respectively. The effects of the buffer layer and back-surface field on the performance of solar cells are discussed. High device performance is achieved in the case of a low concentration of oxygen and weak recombination when InGaAs buffers and InP back-surface field layers are used, respectively.

  13. Characterization of vertical Au/β-Ga2O3 single-crystal Schottky photodiodes with MBE-grown high-resistivity epitaxial layer

    NASA Astrophysics Data System (ADS)

    X, Z. Liu; C, Yue; C, T. Xia; W, L. Zhang

    2016-01-01

    High-resistivity β-Ga2O3 thin films were grown on Si-doped n-type conductive β-Ga2O3 single crystals by molecular beam epitaxy (MBE). Vertical-type Schottky diodes were fabricated, and the electrical properties of the Schottky diodes were studied in this letter. The ideality factor and the series resistance of the Schottky diodes were estimated to be about 1.4 and 4.6× 106 Ω. The ionized donor concentration and the spreading voltage in the Schottky diodes region are about 4 × 1018 cm-3 and 7.6 V, respectively. The ultra-violet (UV) photo-sensitivity of the Schottky diodes was demonstrated by a low-pressure mercury lamp illumination. A photoresponsivity of 1.8 A/W and an external quantum efficiency of 8.7 × 102% were observed at forward bias voltage of 3.8 V, the proper driving voltage of read-out integrated circuit for UV camera. The gain of the Schottky diode was attributed to the existence of a potential barrier in the i-n junction between the MBE-grown highly resistive β-Ga2O3 thin films and the n-type conductive β-Ga2O3 single-crystal substrate. Project supported by the National Nature Science Foundation of China (Grant No. 61223002) the Science and Technology Commission of Shanghai Municipality, China (Grant No. 13111103700), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 2012018530003).

  14. Special Features of Admittance in Mis Structures Based on Graded-Gap MBE n-Hg1- x Cd x Te ( x = 0.31-0.32) in a Temperature Range OF 8-300 K

    NASA Astrophysics Data System (ADS)

    Voitsekhovskii, A. V.; Nesmelov, S. N.; Dzyadukh, S. M.; Vasil'ev, V. V.; Varavin, V. S.; Dvoretskii, S. A.; Mikhailov, N. N.; Kuz'min, V. D.; Remesnik, V. G.

    2014-09-01

    Admittance of MIS structures based on graded-gap n-Hg1- х Cd х Te ( x = 0.31-0.32) grown by molecular beam epitaxy (MBE) is investigated in a wide temperature range (8-300 K). It is shown that the temperature and frequency dependences of the differential resistance of space charge region for structures with a graded-gap layer are qualitatively similar to those for structures without a graded-gap layer. It is found that for MIS structures based on MBE n-Hg1- х Cd х Te ( x = 0.31-0.32), regardless of the presence of a graded-gap layer, the differential resistance of space charge region is limited by the processes of Shockley-Read generation in the temperature range of 25-100 K.

  15. Spectroscopic determination of the bandgap crossover composition in MBE-grown AlxGa1-xAs

    DOE PAGESBeta

    Fluegel, Brian; Alberi, Kirstin; Reno, John; Mascarenhas, Angelo

    2015-03-12

    The aluminum concentration dependence of the energies of the direct and indirect bandgaps arising from the Γ and X conduction bands are measured at 1.7 K in the semiconductor alloy AlxGa1-xAs. The composition at which the bands cross is determined from photoluminescence of molecular-beam epitaxy samples grown very close to crossover. The use of resonant laser excitation and the improved sample linewidth allows precise determination of the bound exciton transition energies. Moreover, photoluminescence excitation spectroscopy is used to measure the binding energies of the donor-bound excitons and the Γ free exciton binding energy.

  16. Lattice-engineered MBE growth of high-indium mole fraction InGaAs for low cost MMICs and (1.3--1.55 {micro}m) OEICs

    SciTech Connect

    Childs, T.T.; Sokolov, V.; Sullivan, C.T.

    1997-11-01

    Using molecular beam epitaxy (MBE) and lattice engineering techniques, the feasibility of combining photonic devices applicable to the 1.3 to 1.55 {micro}m wavelength range and monolithic microwave (or mm-wave) integrated circuits (MMICs) on GaAs is demonstrated. A key factor in the MBE growth is incorporation of an InGaAs active layer having an indium arsenide mole fraction of 0.35 or greater and its lattice compatibility with the underlying semi-insulating GaAs substrate. The InGaAs layer used for the photonic devices, can also serve as the active channel for the high electron mobility transistors (HEMTs) for application in MMICs. Several examples of active and passive photonic devices grown by MBE are presented including an optical ridge waveguide, and a photodetector for detection of light in the 1.3 {micro}m range. The material structure includes a 3-layer AlGaAs/GaAs/AlGaAs optical waveguide and a thin InGaAs absorbing layer situated directly above the optical waveguide. Metal-semiconductor-metal (MSM) photodetectors are formed on the top surface of the InGaAs layer for collection of the photo-induced carriers. The optical ridge waveguide is designed for lateral incidence of the light to enhance the MSM photodetector responsivity. Initial measurements on the optical waveguide and photodetector are presented.

  17. ZnO film with ultra-low background electron concentration grown by plasma-assisted MBE using Mg film as the buffer layer

    SciTech Connect

    Chen, Mingming; Zhang, Quanlin; Su, Longxing; Su, Yuquan; Cao, Jiashi; Zhu, Yuan; Wu, Tianzhun; Gui, Xuchun; Yang, Chunlei; Xiang, Rong; Tang, Zikang

    2012-09-15

    Highlights: ► High quality ZnO film with ultra-low background electron concentration is grown by plasma-assisted molecular beam epitaxy using Mg film as a buffer layer. ► High resolution X-ray diffraction and photoluminescence (PL) spectroscopy indicate a high degree of crystallization. ► Hall measurement shows a carrier concentration as low as ∼10{sup 14} cm{sup −3}. ► The mechanism of the improved crystallinity is discussed in detail. -- Abstract: High quality ZnO epilayer with background electron concentration as low as 2.6 × 10{sup 14} cm{sup −3} was obtained by plasma-assisted MBE on c-sapphire using a thin Mg film as the buffer layer. High-resolution XRD measurement shows a sharp (0 0 2) peak with full width at half maximum (FWHM) of only 0.029°. Photoluminescence spectroscopy presents a weak defect-related near-edge emission. A metal–semiconductor–metal (MSM) typed photodetector based on the material demonstrates a response of ∼43 A/W under the bias of 1 V and an ON/OFF ratio of 10{sup 4}. This un-doped ZnO with ultra-low background electron concentration could be a promising starting material for p-type doping.

  18. MBE growth and transport properties of silicon δ-doped GaAs/AlAs quantum well structures for terahertz frequency detection

    NASA Astrophysics Data System (ADS)

    Lachab, M.; Khanna, S. P.; Harrison, P.; Linfield, E. H.; Čerškus, A.; Kundrotas, J.; Seliuta, D.; Valušis, G.

    2010-04-01

    We present the electrical characterization of n-type GaAs/AlAs multiple quantum well (MQW) structures designed for terahertz (THz) radiation sensing at cryogenic temperatures. The samples were grown by solid source molecular beam epitaxy (MBE) and were δ-doped with silicon atoms at each potential well center. Temperature dependent Hall effect data show that (i) the conduction in these planar doped structures is thermally activated below 180 K, (ii) the free carriers sheet densities are near the metal-insulator transition, and (iii) the low temperature mobility is controlled by ionized impurities scattering. The study of the magneto-transport properties at 1.3 K further indicates that only the fundamental electronic sub-band of the two-dimensional electronic gas is populated. The MQW samples were then processed into lateral mesa-shaped photodetectors to investigate their spectral response in the THz frequency range. The preliminary experimental results for the proposed detection scheme, which involves transitions in the confined shallow donor impurity states, are described.

  19. Structural and optical studies of GaN pn-junction with AlN buffer layer grown on Si (111) by RF plasma enhanced MBE

    NASA Astrophysics Data System (ADS)

    Yusoff, Mohd Zaki Mohd; Hassan, Zainuriah; Woei, Chin Che; Hassan, Haslan Abu; Abdullah, Mat Johar

    2012-06-01

    GaN pn-junction grown on silicon substrates have been the focus in a number of recent reports and further effort is still necessary to improve its crystalline quality for practical applications. GaN has the high n-type background carrier concentration resulting from native defects commonly thought to be nitrogen vacancies. In this work, we present the growth of pn-junction of GaN on Si (111) substrate using RF plasma-enhanced molecular beam epitaxy (MBE). Both of the layers show uniformity with an average thickness of 0.709 μm and 0.095 μm for GaN and AlN layers, respectively. The XRD spectra indicate that no sign of cubic phase of GaN are found, so it is confirmed that the sample possessed hexagonal structure. It was found that all the allowed Raman optical phonon modes of GaN, i.e. the E2 (low), E1 (high) and A1 (LO) are clearly visible.

  20. Structural and optical studies of GaN pn-junction with AlN buffer layer grown on Si (111) by RF plasma enhanced MBE

    SciTech Connect

    Yusoff, Mohd Zaki Mohd; Hassan, Zainuriah; Woei, Chin Che; Hassan, Haslan Abu; Abdullah, Mat Johar

    2012-06-29

    GaN pn-junction grown on silicon substrates have been the focus in a number of recent reports and further effort is still necessary to improve its crystalline quality for practical applications. GaN has the high n-type background carrier concentration resulting from native defects commonly thought to be nitrogen vacancies. In this work, we present the growth of pn-junction of GaN on Si (111) substrate using RF plasma-enhanced molecular beam epitaxy (MBE). Both of the layers show uniformity with an average thickness of 0.709 {mu}m and 0.095 {mu}m for GaN and AlN layers, respectively. The XRD spectra indicate that no sign of cubic phase of GaN are found, so it is confirmed that the sample possessed hexagonal structure. It was found that all the allowed Raman optical phonon modes of GaN, i.e. the E2 (low), E1 (high) and A1 (LO) are clearly visible.

  1. The long noncoding RNAs PVT1 and uc002mbe.2 in sera provide a new supplementary method for hepatocellular carcinoma diagnosis.

    PubMed

    Yu, Jinyu; Han, Junqing; Zhang, Jian; Li, Guanzhen; Liu, Hui; Cui, Xianping; Xu, Yantian; Li, Tao; Liu, Juan; Wang, Chuanxi

    2016-08-01

    Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver in adults worldwide. Several studies have demonstrated that long noncoding RNAs (lncRNAs) are involved in the development of various types of cancer, including HCC. These findings prompted us to examine the detectability of lncRNAs in blood samples from patients with HCC. In this study, we explored the expression levels of 31 cancer-related lncRNAs in sera from 71 HCC patients and 64 healthy individuals by reverse transcription and quantitative polymerase chain reaction (RT-qPCR). We found that 25 lncRNAs could be detected in the serum and that 7 had significantly different expression levels. A 2-lncRNA signature (PVT1 and uc002mbe.2) identified by stepwise regression showed potential as a diagnostic marker for HCC. The area under the receiver operating characteristic (ROC) curve was 0.764 (95% CI: 0.684-0.833). The sensitivity and specificity values of this serum 2-lncRNA signature for distinguishing HCC patients from the healthy group were 60.56% and 90.62%, respectively. The diagnostic ability of the combination of the serum 2-lncRNA signature with alpha-fetoprotein (AFP) was much greater than that of AFP alone. The expression levels of the 2 lncRNAs were associated with clinical parameters including tumor size, Barcelona Clinic Liver Cancer (BCLC) stage, and serum bilirubin. PMID:27495068

  2. The MBE growth and optical quality of BaTiO{sub 3} and SrTiO{sub 3} thin films on MgO

    SciTech Connect

    McKee, R.A.; Specht, E.D.; Alexander, K.B.; Walker, F.J.

    1994-05-01

    High quality epitaxial BaTiO{sub 3} and SrTiO{sub 3} have been grown on MgO; stabilized at a one unit cell height; and grown to film thicknesses of 0.5--0.7 {mu}m. These relatively thick films remain adherent when thermally cycled between growth temperatures and room temperature, are crack free with high optical quality, and have both in-plane and out-of-plane X-ray rocking curves of 0.3--0.5{degree}. These films have been grown using molecular beam epitaxy (MBE) methods starting with the TiO{sub 2} layer of the perovskite structure. The TiO{sub 2}-layer/MgO interface uniquely satisfies electrostatic requirements for perovskite heteroepitaxy and provides the template structure that leads to the high quality films that are obtained. Wavelength dependence of optical loss has been characterized between 475 nm and 705 nm with loss coefficients < l dB/cm being obtained at the He-Ne wavelength.

  3. Structural and Magnetotransport Studies of MBE-grown Pn(Sn)Te films and PbTe:Bi/CdTe Quantum Wells

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Liu, Xinyu; Furdyna, Jacek; Dobrowolska, Malgorzata; Wojtowicz, Tomasz

    2014-03-01

    Recent studies confirmed the existence of topological crystalline insulators (TCIs), in which crystalline symmetry replaces the role of time-reversal symmetry in ensuring topological protection. In the narrow-gap semiconductor TCIs, chemical potential can be tuned by modifications of crystal growth and/or annealing to yield n-type or p-type conductivity, which makes them especially well-suited for magnetotransport measurements. In this work, we have grown a series of Pb1-xSnxTe films and PbTe:Bi/CdTe QWs on CdTe/GaAs(100) substrates using MBE. Structural studies of these thin films were carried out using XRD and SEM techniques. XRD results shows satisfactory crystal quality of Pb(Sn)Te films grown on CdTe. SEM studies show the presence of inclusions in the films, indicating that the crystal quality still requires improvement. Magnetostransport studies of PbTe:Bi/CdTe QWs suggests that Bi acts as a donor in PbTe, and the electron mobility in the 2D electron gas in the QW depends on the growth conditions, such as substrate temperature. The study of Pb1-xSnxTe QWs is currently underway, and will also be discussed in this talk.

  4. The long noncoding RNAs PVT1 and uc002mbe.2 in sera provide a new supplementary method for hepatocellular carcinoma diagnosis

    PubMed Central

    Yu, Jinyu; Han, Junqing; Zhang, Jian; Li, Guanzhen; Liu, Hui; Cui, Xianping; Xu, Yantian; Li, Tao; Liu, Juan; Wang, Chuanxi

    2016-01-01

    Abstract Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver in adults worldwide. Several studies have demonstrated that long noncoding RNAs (lncRNAs) are involved in the development of various types of cancer, including HCC. These findings prompted us to examine the detectability of lncRNAs in blood samples from patients with HCC. In this study, we explored the expression levels of 31 cancer-related lncRNAs in sera from 71 HCC patients and 64 healthy individuals by reverse transcription and quantitative polymerase chain reaction (RT-qPCR). We found that 25 lncRNAs could be detected in the serum and that 7 had significantly different expression levels. A 2-lncRNA signature (PVT1 and uc002mbe.2) identified by stepwise regression showed potential as a diagnostic marker for HCC. The area under the receiver operating characteristic (ROC) curve was 0.764 (95% CI: 0.684–0.833). The sensitivity and specificity values of this serum 2-lncRNA signature for distinguishing HCC patients from the healthy group were 60.56% and 90.62%, respectively. The diagnostic ability of the combination of the serum 2-lncRNA signature with alpha-fetoprotein (AFP) was much greater than that of AFP alone. The expression levels of the 2 lncRNAs were associated with clinical parameters including tumor size, Barcelona Clinic Liver Cancer (BCLC) stage, and serum bilirubin. PMID:27495068

  5. Comprehensive strain and band gap analysis of PA-MBE grown AlGaN/GaN heterostructures on sapphire with ultra thin buffer

    SciTech Connect

    Mahata, Mihir Kumar; Ghosh, Saptarsi; Jana, Sanjay Kumar; Bag, Ankush; Kumar, Rahul; Chakraborty, Apurba; Biswas, Dhrubes; Mukhopadhyay, Partha

    2014-11-15

    In this work, cluster tool (CT) Plasma Assisted Molecular Beam Epitaxy (PA-MBE) grown AlGaN/GaN heterostructure on c-plane (0 0 0 1) sapphire (Al{sub 2}O{sub 3}) were investigated by High Resolution X-ray Diffraction (HRXRD), Room Temperature Raman Spectroscopy (RTRS), and Room Temperature Photoluminescence (RTPL). The effects of strain and doping on GaN and AlGaN layers were investigated thoroughly. The out-of-plane (‘c’) and in-plane (‘a’) lattice parameters were measured from RTRS analysis and as well as reciprocal space mapping (RSM) from HRXRD scan of (002) and (105) plane. The in-plane (out-of plane) strain of the samples were found to be −2.5 × 10{sup −3}(1 × 10{sup −3}), and −1.7 × 10{sup −3}(2 × 10{sup −3}) in GaN layer and 5.1 × 10{sup −3} (−3.3 × 10{sup −3}), and 8.8 × 10{sup −3}(−1.3 × 10{sup −3}) in AlGaN layer, respectively. In addition, the band structures of AlGaN/GaN interface were estimated by both theoretical (based on elastic theory) and experimental observations of the RTPL spectrum.

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

    SciTech Connect

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

    2014-12-15

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

  7. Influence of High Nitrogen Flux on Crystal Quality of Plasma-Assisted MBE Grown GaN Layers Using Raman Spectroscopy: Part-II

    SciTech Connect

    Asghar, M.; Hussain, I.; Islah u din; Saleemi, F.

    2007-05-09

    We have investigated lattice properties of plasma assisted MBE grown hexagonal GaN layers at varying nitrogen and gallium fluxes using Raman spectroscopy. Room temperature Raman spectra of Ga-rich layers and stoichiometric GaN are similar showing excitation modes at 434 cm-1, 567 cm-1 and 729 cm-1 identified as residual laser line, E{sub 2}{sup H} and A1(LO) mode, respectively. Similarity of Ga-rich and stoichiometric GaN layers is interpreted as the indication of comparable crystal quality of both GaN layers. In contrast, Raman scattering associated with N-rich GaN samples mere exhibit a broad band of excitations in the range of 250-650cm-1 leaving out A1(LO) mode. This typical observation along with intensity distribution of the peaks, is correlated with rough surface, bad crystal quality and high concentration of defects. Based on atomic displacement scheme, the broad band is identified as Ga- vacancies.

  8. The impact of RF-plasma power in carrier relaxation dynamics of unintentional doped GaN epitaxial layers grown by MBE

    NASA Astrophysics Data System (ADS)

    Prakash, Nisha; Anand, Kritika; Barvat, Arun; Pal, Prabir; Singh, Dilip K.; Jewariya, Mukesh; Ragam, Srinivasa; Adhikari, Sonachand; Maurya, Kamlesh K.; Khanna, Suraj P.

    2016-04-01

    In this work, unintentionally doped GaN samples were prepared on GaN template by radio frequency (RF)-plasma MBE technique using two different RF-plasma powers. Photoluminescence (PL), steady state photoconductivity (PC) and ultrafast optical pump-probe spectroscopy measurements have been carried out to characterize the samples. The effect of RF-plasma power towards unintentional doping and giving rise to yellow luminescence (YL) is discussed. Our PC measurements show relatively faster decay for sample grown with higher RF-plasma power. In addition, the ultrafast optical pump-probe spectroscopy results show the presence of various defect levels with different relaxation times. A faster ultrafast relaxation time from the conduction band to the closest defect level and conduction band to the next defect level was observed for the sample grown with higher plasma power. A comparatively low defect density and faster carrier relaxation observed in higher RF-plasma power grown samples is caused by lower impurities and gallium vacancies. The results imply that RF-plasma power is very important parameter for the growth of epitaxial GaN films and undesirable impurities and gallium vacancies might get incorporated in the epitaxial GaN films.

  9. GaInP/GaAs tandem solar cells with highly Te- and Mg-doped GaAs tunnel junctions grown by MBE

    NASA Astrophysics Data System (ADS)

    Zheng, Xin-He; Liu, San-Jie; Xia, Yu; Gan, Xing-Yuan; Wang, Hai-Xiao; Wang, Nai-Ming; Yang, Hui

    2015-10-01

    We report a GaInP/GaAs tandem solar cell with a novel GaAs tunnel junction (TJ) with using tellurium (Te) and magnesium (Mg) as n- and p-type dopants via dual-filament low temperature effusion cells grown by molecular beam epitaxy (MBE) at low temperature. The test Te/Mg-doped GaAs TJ shows a peak current density of 21 A/cm2. The tandem solar cell by the Te/Mg TJ shows a short-circuit current density of 12 mA/cm2, but a low open-circuit voltage range of 1.4 V˜1.71 V under AM1.5 illumination. The secondary ion mass spectroscopy (SIMS) analysis reveals that the Te doping is unexpectedly high and its doping profile extends to the Mg doping region, thus possibly resulting in a less abrupt junction with no tunneling carriers effectively. Furthermore, the tunneling interface shifts from the intended GaAs n++/p++ junction to the AlGaInP/GaAs junction with a higher bandgap AlGaInP tunneling layers, thereby reducing the tunneling peak. The Te concentration of ˜ 2.5 × 1020 in GaAs could cause a lattice strain of 10-3 in magnitude and thus a surface roughening, which also negatively influences the subsequent growth of the top subcell and the GaAs contacting layers. The doping features of Te and Mg are discussed to understand the photovoltaic response of the studied tandem cell. Project supported by the SINANO-SONY Joint Program (Grant No. Y1AAQ11001), the National Natural Science Foundation of China (Grant No. 61274134), the USCB Start-up Program (Grant No. 06105033), and the International Cooperation Projects of Suzhou City, China (Grant No. SH201215).

  10. Formation and Temperature Effect of InN Nanodots by PA-MBE via Droplet Epitaxy Technique.

    PubMed

    Chen, Hugo Juin-Yu; Yang, Dian-Long; Huang, Tseh-Wet; Yu, Ing-Song

    2016-12-01

    In this report, self-organized indium nitride nanodots have been grown on Si (111) by droplet epitaxy method and their density can reach as high as 2.83 × 10(11) cm(-2) for the growth at low temperature of 250 °C. Based on the in situ reflection high-energy electron diffraction, the surface condition, indium droplets, and the formation of InN nanodots are identified during the epitaxy. The X-ray photoelectron spectroscopy and photoluminescence measurements have shown the formation of InN nanodots as well. The growth mechanism of InN nanodots could be described via the characterizations of indium droplets and InN nanodots using scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The density of the InN nanodots was less than that of the In droplets due to the surface diffusion and desorption of atoms during the nitridation and annealing process. The average size and density of InN nanodots can be controlled by the substrate temperatures during the growth. For the growth at lower temperature, we obtained the higher density and smaller average size of InN nanodots. To minimize the total surface energy, the coarsening and some preferred orientations of InN nanodots were observed for the growth at high temperature. PMID:27142879

  11. Surface roughness estimation of MBE grown CdTe/GaAs(211)B by ex-situ spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Karakaya, Merve; Bilgilisoy, Elif; Arı, Ozan; Selamet, Yusuf

    2016-07-01

    Spectroscopic ellipsometry (SE) ranging from 1.24 eV to 5.05 eV is used to obtain the film thickness and optical properties of high index (211) CdTe films. A three-layer optical model (oxide/CdTe/GaAs) was chosen for the ex-situ ellipsometric data analysis. Surface roughness cannot be determined by the optical model if oxide is included. We show that roughness can be accurately estimated, without any optical model, by utilizing the correlation between SE data (namely the imaginary part of the dielectric function, <ɛ2 > or phase angle, ψ) and atomic force microscopy (AFM) roughness. <ɛ2 > and ψ values at 3.31 eV, which corresponds to E1 critical transition energy of CdTe band structure, are chosen for the correlation since E1 gives higher resolution than the other critical transition energies. On the other hand, due to the anisotropic characteristic of (211) oriented CdTe surfaces, SE data (<ɛ2 > and ψ) shows varieties for different azimuthal angle measurements. For this reason, in order to estimate the surface roughness by considering these correlations, it is shown that SE measurements need to be taken at the same surface azimuthal angle. Estimating surface roughness in this manner is an accurate way to eliminate cumbersome surface roughness measurement by AFM.

  12. Formation and Temperature Effect of InN Nanodots by PA-MBE via Droplet Epitaxy Technique

    NASA Astrophysics Data System (ADS)

    Chen, Hugo Juin-Yu; Yang, Dian-Long; Huang, Tseh-Wet; Yu, Ing-Song

    2016-05-01

    In this report, self-organized indium nitride nanodots have been grown on Si (111) by droplet epitaxy method and their density can reach as high as 2.83 × 1011 cm-2 for the growth at low temperature of 250 °C. Based on the in situ reflection high-energy electron diffraction, the surface condition, indium droplets, and the formation of InN nanodots are identified during the epitaxy. The X-ray photoelectron spectroscopy and photoluminescence measurements have shown the formation of InN nanodots as well. The growth mechanism of InN nanodots could be described via the characterizations of indium droplets and InN nanodots using scanning electron microscopy, atomic force microscopy, and transmission electron microscopy. The density of the InN nanodots was less than that of the In droplets due to the surface diffusion and desorption of atoms during the nitridation and annealing process. The average size and density of InN nanodots can be controlled by the substrate temperatures during the growth. For the growth at lower temperature, we obtained the higher density and smaller average size of InN nanodots. To minimize the total surface energy, the coarsening and some preferred orientations of InN nanodots were observed for the growth at high temperature.

  13. MBE growth and transport of the topologically tunable (Bi1-x In x)2Se3 system

    NASA Astrophysics Data System (ADS)

    Brahlek, Matthew; Bansal, Namrata; Koirala, Nikesh; Xu, Suyang; Hasan, Zahid; Oh, Seongshik

    2012-02-01

    A current challenge in the field of topological insulators (TI) is identifying a clear transport signal of the surface conduction. The structural similarity between Bi2Se3 and In2Se3 allowed us to combine the two to obtain (Bi1-x In x)2Se3; Bi2Se3 has inverted bands, and thus is a non-trivial insulator. In2Se3 has no inverted bands and is therefore a trivial band insulator with energy gap 1.3-1.9eV. The mixing ratio x can be thought of as a knob to switch the system from a trivial to a non-trivial state. I will briefly discuss our scheme for producing atomically smooth molecular beam epitaxial grown thin films. I will also discuss our work on transport in the TI-to-non TI regime, and the metal to insulator regime, and compare these results with angle resolved photo emission spectroscopy data.

  14. Study of InN nanorods growth mechanism using ultrathin Au layer by plasma-assisted MBE on Si(111)

    NASA Astrophysics Data System (ADS)

    Kumar, Mahesh; Rajpalke, Mohana K.; Roul, Basanta; Bhat, Thirumaleshwara N.; Krupanidhi, S. B.

    2014-01-01

    InN nanorods (NRs) were grown on Si(111) substrate by plasma-assisted molecular beam epitaxy. The growth of InN NRs has been demonstrated using an electron-beam evaporated (~2 nm) Au layer prior to the initiation of growth. The structure and morphology of as deposited Au film, annealed at 600 °C, and InN NRs were investigated using X-ray photoelectron spectroscopy and scanning electron microscopy. Chemical characterization was performed with energy dispersive X-ray analysis. Single-crystalline wurtzite structure of InN NRs is verified by transmission electron microscopy. The formation process of NRs is investigated and a qualitative mechanism is proposed.

  15. A review of MBE grown 0D, 1D and 2D quantum structures in a nanowire

    NASA Astrophysics Data System (ADS)

    de la Mata, Maria; Zhou, Xiang; Furtmayr, Florian; Teubert, Jörg; Gradecak, Silvija; Eickhoff, Martin; Fontcuberta i Morral, Anna; Arbiol, Jordi

    2013-05-01

    We review different strategies to achieve a three-dimensional energy bandgap modulation in a nanowire (NW) by the introduction of self-assembled 0D, 1D and 2D quantum structures, quantum dots (QDs), quantum wires (QWRs) and quantum wells (QWs). Starting with the well-known axial, radial (coaxial/prismatic) or polytypic quantum wells in GaN/AlN, GaAs/AlAs or wurtzite/zinc-blende systems, respectively, we move to more sophisticated structures by lowering their dimensionality. New recent approaches developed for the self-assembly of GaN quantum wires and InAs or AlGaAs quantum dots on single nanowire templates are reported and discussed. Aberration corrected scanning transmission electron microcopy is presented as a powerful tool to determine the structure and morphology at the atomic scale allowing for the creation of 3D atomic models that can help us to understand the enhanced optical properties of these advanced quantum structures.

  16. Formation of Metal-Semiconductor Interfaces on Mbe-Grown Gallium ARSENIDE(100): Surface Photovoltage, Chemistry and Band Bending

    NASA Astrophysics Data System (ADS)

    Mao, Duli

    1992-01-01

    The chemical, structural and electronic properties of the metal-GaAs interfaces formed on the polar (100) surface are studied using high resolution core level photoemission spectroscopy (PES) and low energy electron diffraction (LEED). The clean (4 x 2)-c(8 x 2) reconstructed GaAs(100) surface, prepared by molecular beam epitaxy and subsequent thermal decapping of an As protective layer, is characterized carefully. Ga 3d and As 3d core levels are analyzed using test square curve fitting. Two Ga surface components are resolved while only one surface component is necessary for As. The assignment of these surface components to different surface atomic arrangements is discussed. The surface Fermi level position with respect to the valence band maximum is also investigated as a function of decapping temperature. Metal (In, Ga, Au)/GaAs(100) interfaces, formed at both room (RT) and low temperature (LT), are studied. The morphology of these interfaces resembles that of metal/GaAs(110) interfaces formed at LT, in that the deposited metal atoms reside at the surface as isolated adatoms rather than as clusters at submonolayer coverage. Metal clustering is only important at coverages higher than a few monolayers and is more prominent at RT than at LT. The GaAs(100) band bending is studied as a function of metal coverage and deposition temperature. At submonolayer metal coverages, In and Ga both cause reduced band bending (~ 0.2eV) on n-type GaAs, a phenomenon similar to the Fermi level overshoot observed at LT-formed metal/p-GaAs(110) interfaces and indicative of formation of adatom-induced donor levels in the upper part of the band gap. With Au, In and Ga, the Fermi level is pinned at 0.4eV, 0.6eV and 0.68eV above the valence band maximum respectively, in good agreement with the results obtained at metal/GaAs(110) interfaces. This contradicts recent claims of near-Schottky limit for these interfaces. Evidence of correlation between pinning and overlayer metallization is

  17. Energy.

    ERIC Educational Resources Information Center

    Online-Offline, 1998

    1998-01-01

    This issue focuses on the theme of "Energy," and describes several educational resources (Web sites, CD-ROMs and software, videos, books, activities, and other resources). Sidebars offer features on alternative energy, animal energy, internal combustion engines, and energy from food. Subthemes include harnessing energy, human energy, and natural…

  18. Electron beam pumping of CdZnSe quantum well laser structures using a variable energy electron beam

    NASA Astrophysics Data System (ADS)

    Trager-Cowan, C.; Bagnall, D. M.; McGow, F.; McCallum, W.; O'Donnell, K. P.; Smith, P. C.; Wright, P. J.; Cockayne, B.; Prior, K. A.; Mullins, J. T.; Horsburgh, G.; Cavenett, B. C.

    1996-02-01

    In this paper we present experimental results on electron beam pumping of MBE and MOVPE lasers with CdZnSe single quantum wells. Laser emission in the gree and blue occurs under pulsed excitation, with threshold power densities typically less than 2 kW/cm 2 at low temperatures. Threshold curves obtained at different electron beam energies show that there is an optimum electron beam energy for wells at a given depth below the surface. This suggests that it is possible to match the electron beam energy to a given structure. Results are broadly consistent with Monte Carlo calculations of the depth dependence of the energy deposition of the electron beam.

  19. Effects of MgO buffer annealing on optical and electrical quality of P-MBE grown ZnO films on c-sapphire

    NASA Astrophysics Data System (ADS)

    Setiawan, A.; Yao, T.

    2016-04-01

    Zinc oxide (ZnO) has been attracting much attention because of its potential applications in photonic and optoelectronic devices. In this present study, we investigated the effect of MgO buffer annealing on the optical and electrical quality of P-MBE grown ZnO films on c-sapphire with MgO buffer layer. The optical quality was observed by low-temperature PL (photoluminescence) measurement in the near band edge emission region measured at 10K and at 77K. The emission line located at 3.368eV dominates the spectrum in both samples (ZnO with and without MgO buffer annealing) at 10K and 77K. This emission can be divided into two peaks, 3.367eV and 3.363eV and assigned as I2 (ionized donor bound excitons emission) and I4 (Hydrogen donor related emission), respectively. The relative intensity of these donor bound exactions to free exaction emission of the sample without MgO buffer annealing is greater than that of the sample with MgO buffer annealing. Comparison of the PL spectra of ZnO with and without annealing revealed that the intensity of free exciton emission from the sample with MgO buffer annealing is twice of that from the sample without annealing. We also found that the intensity of deep-level broad emission is reduced by about 1/3 by MgO-buffer annealing. Hence, the decrease of deep level emission intensity and the increase of free exciton emission intensity by annealing of MgO buffer corresponds to the reduction of defects of the ZnO film. The PL properties also suggest that there are fewer nonradiative recombination centers in ZnO layers with MgO buffer annealing than those in ZnO layers grown without MgO buffer annealing. The electrical quality was measured by room temperature Hall measurements. We found that the samples have a background n-type carrier concentration. The ZnO samples with MgO buffer annealing has a carrier concentration of 1.17×1017 cm-3 and Hall mobility of 120 cm2/V.s, while the ZnO sample without MgO buffer annealing has a carrier

  20. Molecular-beam epitaxy of monolayer and bilayer WSe2: a scanning tunneling microscopy/spectroscopy study and deduction of exciton binding energy

    NASA Astrophysics Data System (ADS)

    Liu, H. J.; Jiao, L.; Xie, L.; Yang, F.; Chen, J. L.; Ho, W. K.; Gao, C. L.; Jia, J. F.; Cui, X. D.; Xie, M. H.

    2015-09-01

    Interest in two-dimensional (2D) transition-metal dichalcogenides (TMDs) has prompted some recent efforts to grow ultrathin layers of these materials epitaxially using molecular-beam epitaxy (MBE). However, growths of monolayer (ML) and bilayer (BL) WSe2—an important member of the TMD family—by the MBE method remain uncharted, probably because of the difficulty in generating tungsten fluxes from the elemental source. In this work, we present a scanning tunneling microscopy and spectroscopy (STM/S) study of MBE-grown WSe2 ML and BL, showing atomically flat epifilm with no domain boundary (DB) defect. This contrasts epitaxial MoSe2 films grown by the same method, where a dense network of the DB defects is present. The STS measurements of ML and BL WSe2 domains of the same sample reveal not only the bandgap narrowing upon increasing the film thickness from ML to BL, but also a band-bending effect across the boundary (step) between ML and BL domains. This band-bending appears to be dictated by the edge states at steps of the BL islands. Finally, comparison is made between the STS-measured electronic bandgaps with the exciton emission energies measured by photoluminescence, and the exciton binding energies in ML and BL WSe2 (and MoSe2) are thus estimated.

  1. Analysis of GaSb and AlSb reconstructions on GaSb(111) A- and B-oriented surfaces by azimuthal-scan reflection high-energy electron diffraction

    NASA Astrophysics Data System (ADS)

    Proessdorf, Andre; Grosse, Frank; Braun, Wolfgang; Katmis, Ferhat; Riechert, Henning; Romanyuk, Oleksandr

    2011-04-01

    The symmetry and existence ranges of GaSb and AlSb (111) A and B surface reconstructions are investigated using azimuthal-scan reflection high-energy electron diffraction (ARHEED) in a molecular-beam-epitaxy (MBE) environment. ARHEED patterns of all reconstructions within the accessible MBE group V flux-substrate temperature parameter field are presented and analyzed. The transition borders are mapped out as a reference for future growth experiments. The experimental results are interpreted on the basis of general construction principles for (111) surfaces of III-V semiconductors. ARHEED allows the complete determination of the two-dimensional in-plane reciprocal lattice in a single, continuous measurement. This allows the unambiguous identification of the reconstructions on (111) surfaces where the intrinsic symmetry is masked by the 120° domain structure and possible disorder.

  2. Energy.

    PubMed

    Chambers, David W

    2012-01-01

    Energy is the capacity to do the things we are capable of and desire to accomplish. Most often this is thought of in terms of PEP--personal energy potential--a reservoir of individual vivacity and zest for work. Like a battery, energy can be conceived of as a resource that is alternatively used and replenished. Transitions between activities, variety of tasks, and choices of what to spend energy on are part of energy management. Energy capacity can be thought of at four levels: (a) so little that harm is caused and extraordinary steps are needed for recovery, (b) a deficit that slightly impairs performance but will recover naturally, (c) the typical range of functioning, and (d) a surplus that may or may not be useful and requires continual investment to maintain. "Flow" is the experience of optimal energy use when challenges balance capacity as a result of imposing order on our environment. There are other energy resources in addition to personal vim. Effective work design reduces demands on energy. Money, office design, and knowledge are excellent substitutes for personal energy. PMID:22856055

  3. Spectroscopic determination of the bandgap crossover composition in MBE-grown AlxGa1-xAs

    SciTech Connect

    Fluegel, Brian; Alberi, Kirstin; Reno, John; Mascarenhas, Angelo

    2015-03-12

    The aluminum concentration dependence of the energies of the direct and indirect bandgaps arising from the Γ and X conduction bands are measured at 1.7 K in the semiconductor alloy AlxGa1-xAs. The composition at which the bands cross is determined from photoluminescence of molecular-beam epitaxy samples grown very close to crossover. The use of resonant laser excitation and the improved sample linewidth allows precise determination of the bound exciton transition energies. Moreover, photoluminescence excitation spectroscopy is used to measure the binding energies of the donor-bound excitons and the Γ free exciton binding energy.

  4. Capping and decapping of MBE grown GaAs(001), Al 0.5Ga 0.5As(001), and AlAs(001) investigated with ASP, PES, LEED, and RHEED

    NASA Astrophysics Data System (ADS)

    Bernstein, R. W.; Borg, A.; Husby, H.; Fimland, B.-O.; Grepstad, J. K.

    Arsenic capping and regeneration of MBE-grown GaAs(001), Al 0.5Ga 0.5As(001), and AlAs(001) epilayer surfaces were examined with Auger sputter profiling (ASP), synchrotron radiation and X-ray photoelectron spectroscopy (PES), LEED, and RHEED. It is found that clean, ordered surfaces of different As/Ga(Al) compositions and different surface reconstructions can be prepared in a controlled manner after long-term storage in air, by thermal desorption of the As cap at appropriate annealing temperatures. A protective film of amorphous arsenic was deposited in situ with both As 2 and As 4 molecular beams onto cold substrates. The recorded Auger depth profiles unveil capping layer thicknesses from 0.3 to 3 μm, the thicker for depositions using the As 2 dimer source. The As 3+ surface oxide, formed immediately upon exposure of the passivated wafers to air, remains on the order of 10Åthick, even after storage in atmosphere for several months. Core level photoemission shows selective desorption of this oxide upon annealing in UHV at 250°C. Further heating at 350°C evaporates the protective arsenic cap, and clean, As-terminated Al xGa 1- xAs(001) surfaces with a regular arrayof chemisorbed excess As sbnd As dimers prevail. The recorded LEED and RHEED patterns show a c(4 × 4) surface reconstruction for GaAs(001) and Al 0.5Ga 0.5As(001), whereas this structural phase was observed with RHEED only for the highly reactive AlAs(001) surface. Subsequently annealing in UHV at 450°C causes desorption of the chemisorbed surface arsenic and a concurrent transition from c(4 × 4) to the (2 × 4)/c(2 × 8) surface of As stabilized MBE-grown Al xGa 1- xAs(001). With AlAs(001), surface Al oxidation was observed immediately after annealing at 450°C, in spite of carefully controlled UHV environments

  5. Defects and stresses in MBE-grown GaN and Al{sub 0.3}Ga{sub 0.7}N layers doped by silicon using silane

    SciTech Connect

    Ratnikov, V. V. Kyutt, R. N.; Smirnov, A. N.; Davydov, V. Yu.; Shcheglov, M. P.; Malin, T. V.; Zhuravlev, K. S.

    2013-12-15

    The electric and structural characteristics of silicon-doped GaN and Al{sub 0.3}Ga{sub 0.7}N layers grown by molecular beam epitaxy (MBE) using silane have been analyzed by the Hall effect, Raman spectroscopy, and high-resolution X-ray diffractometry. It is established that the electron concentration linearly increases up to n = 4 × 10{sup 20} cm{sup −3} with an increase in the silane flow rate for GaN:Si, whereas the corresponding dependence for Al{sub 0.3}Ga{sub 0.7}N:Si is sublinear and the maximum electron concentration is found to be n = 4 × 10{sup 19} cm{sup −3}. X-ray measurements of sample macrobending indicate a decrease in biaxial compressive stress with an increase in the electron concentration in both GaN:Si and Al{sub 0.3}Ga{sub 0.7}N:Si layers. The parameters of the dislocation structure, estimated from the measured broadenings of X-ray reflections, are analyzed.

  6. Adsorption-controlled growth of ferroelectric PbTiO{sub 3} and Bi{sub 4}Ti{sub 3}O{sub 12} films for nonvolatile memory applications by MBE

    SciTech Connect

    Theis, C.D.; Yeh, J.; Schlom, D.G.; Hawley, M.E.; Brown, G.W.

    1997-09-01

    Epitaxial PbTiO{sub 3} and Bi{sub 4}Ti{sub 3}O{sub 12} thin films have been grown on (100) SrTiO{sub 3} and (100) LaAlO{sub 3} substrates by reactive molecular beam epitaxy (MBE). Titanium is supplied to the film in the form of shuttered bursts each containing a one monolayer dose of titanium atoms for the growth of PbTiO{sub 3} and three monolayers for the growth of Bi{sub 4}Ti{sub 3}O{sub 12}. Lead, bismuth, and ozone are continuously supplied to the surface of the depositing film. Growth of phase pure, c-axis oriented epitaxial films with bulk lattice constants is achieved using an overpressure of these volatile species. With the proper choice of substrate temperature (600--650 C) and ozone background pressure (P{sub O{sub 3}} = 2 {times} 10{sup {minus}5} Torr), the excess of the volatile metals and ozone desorb from the surface of the depositing film leaving a phase-pure stoichiometric crystal. The smooth PbTiO{sub 3} surface morphology revealed by atomic force microscopy (AFM) suggests that the PbTiO{sub 3} films grow in a layer-by-layer fashion. In contrast the Bi{sub 4}Ti{sub 3}O{sub 12} films contain islands which evolve either continuously or around screw dislocations via a spiral-type growth mechanism.

  7. Arsenic incorporation in molecular beam epitaxy (MBE) grown (AlGaIn)(AsSb) layers for 2.0-2.5 μm laser structures on GaSb substrates

    NASA Astrophysics Data System (ADS)

    Simanowski, S.; Walther, M.; Schmitz, J.; Kiefer, R.; Herres, N.; Fuchs, F.; Maier, M.; Mermelstein, C.; Wagner, J.; Weimann, G.

    1999-05-01

    The incorporation of As and In during MBE growth in (AlGaIn)/(AsSb) layers used for the fabrication of diode lasers in the 2.0-2.5 μm wavelength range has been investigated. The As content was found to depend linearly on the beam equivalent pressure for As mole fractions between y=0.05 and y=0.20. Broad area AlGaAsSb/GaInAsSb single-quantum well laser diodes with quasi-cw output at room temperature at an emission wavelength of 2.03 μm and a threshold current density of 515 A/cm 2 for 1370 μm long and 70 μm wide devices have been fabricated. In order to shift the emission wavelength of the laser structures to longer wavelengths, the growth of lattice matched AlGaAsSb/GaInAsSb laser core structures with different In and As mole fractions in the quantum wells has been investigated.

  8. Energy.

    ERIC Educational Resources Information Center

    Shanebrook, J. Richard

    This document describes a course designed to acquaint students with the many societal and technological problems facing the United States and the world due to the increasing demand for energy. The course begins with a writing assignment that involves readings on the environmental philosophy of Native Americans and the Chernobyl catastrophe.…

  9. Sb[subscript 2]Te[subscript 3] and Bi[subscript 2]Te[subscript 3] Thin Films Grown by Room-Temperature MBE

    SciTech Connect

    Aabdin, Z.; Peranio, N.; Winkler, M.; Bessas, D.; König, J.; Hermann, R.P.; Böttner, H.; Eibl, O.

    2012-10-23

    Sb{sub 2}Te3 and Bi{sub 2}Te3 thin films were grown on SiO{sub 2} and BaF{sub 2} substrates at room temperature using molecular beam epitaxy. Metallic layers with thicknesses of 0.2 nm were alternately deposited at room temperature, and the films were subsequently annealed at 250 C for 2 h. x-Ray diffraction and energy-filtered transmission electron microscopy (TEM) combined with high-accuracy energy-dispersive x-ray spectrometry revealed stoichiometric films, grain sizes of less than 500 nm, and a texture. High-quality in-plane thermoelectric properties were obtained for Sb{sub 2}Te3 films at room temperature, i.e., low charge carrier density (2.6 x 10{sup 19} cm{sup -3}, large thermopower (130 {micro}V K{sup -1}), large charge carrier mobility (402 cm{sup 2} V{sup -1} s{sup -1}), and resulting large power factor (29 {micro}W cm{sup -1} K{sup -2}). Bi{sub 2}Te3 films also showed low charge carrier density (2.7 x 10{sup 19} cm{sup -3}), moderate thermopower (-153 {micro}V K{sup -1}), but very low charge carrier mobility (80 cm{sup 2} V{sup -1} s{sup -1}), yielding low power factor (8 {micro}W cm{sup -1} K{sup -2}). The low mobilities were attributed to Bi-rich grain boundary phases identified by analytical energy-filtered TEM.

  10. Energy

    SciTech Connect

    Crowley, M.

    1980-01-01

    Nearly 800 organizations are described as sources of information and publications relating to any aspect of energy. The descriptions enable the user to identify organizations by their concerns, goals, and backers as well as their information services. The majority of entries are US organizations, with some international, Canadian, and United Kingdom. Source organizations are arranged alphabetically in eight major categories: Government agencies and quasi-governmental organizations; Activist/civic/public education organizations; Professional/labor/trade asociations; University-affiliated research centers and programs; Independent research organizations; Corporations and other businesses; Publishers, distributors, and information services; and International, foreign agencies, research institutes, corporations, and other associations. The appendices list other grass-roots organizations and sources, title, and subject indices. (DCK)

  11. Compositions and chemical bonding in ceramics by quantitative electron energy-loss spectrometry

    SciTech Connect

    Bentley, J.; Horton, L.L.; McHargue, C.J.; McKernan, S.; Carter, C.B.; Revcolevschi, A.; Tanaka, S.; Davis, R.F.

    1993-12-31

    Quantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L{sub 23} white lines indicated a low-spin state with a charge transfer of {approximately}1.5 electrons/atom onto the Fe atoms implanted into (amorphized) silicon carbide. Gradients of 2 to 5% in the Co:O stoichiometry were measured across 100-nm-thick Co{sub 3}O{sub 4} layers in an oxidized directionally solidified CoO-ZrO{sub 2} eutectic, with the highest O levels near the ZrO{sub 2}. The energy-loss near-edge structures were dramatically different for the two cobalt oxides; those for CO{sub 3}O{sub 4} have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AlN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on {alpha}(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AlN on SiC following annealing at up to 1750C. In diffusion couples of polycrystalline AlN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si{sub 3}N{sub 4}-rich {beta}{prime} sialon in the SiC were detected.

  12. Detailed structural analysis of epitaxial MBE-grown Fe/Cr superlattices by x-ray diffraction and transmission-electron spectroscopy

    SciTech Connect

    Gomez, M.E.; Santamaria, J.; Kim, S.; Schuller, Ivan K.; Krishnan, Kannan M.

    2005-03-15

    We have performed a detailed quantitative structural analysis of epitaxial [Fe(3 nm)/Cr(1.2 nm)]{sub 20} superlattices by low- and high-angle x-ray diffraction, and energy-filtered transmission electron microscopy on cross-section samples. The interface roughness was changed systematically by varying the substrate temperature (150-250 deg. C) maintaining all other growth parameters fixed. Direct imaging of the interfaces allows examining the roughness of the individual interfaces and its evolution with thickness. A statistical analysis of the local interface width for the individual layers supplies the roughness static and dynamic exponents. High-temperature samples (250 deg. C) show roughness decreasing with thickness as a result of surface-diffusion-dominated growth. Low-temperature samples (150 deg. C) show anomalous non-self-affine roughness characterized by a time-dependent local interface width.

  13. Initial stage growth of GexSi1−x layers and Ge quantum dot formation on GexSi1−x surface by MBE

    PubMed Central

    2012-01-01

    Critical thicknesses of two-dimensional to three-dimensional growth in GexSi1−x layers were measured as a function of composition for different growth temperatures. In addition to the (2 × 1) superstructure for a Ge film grown on Si(100), the GexSi1−x layers are characterized by the formation of (2 × n) reconstruction. We measured n for all layers of Ge/GexSi1−x/Ge heterosystem using our software with respect to the video recording of reflection high-energy electron diffraction (RHEED) pattern during growth. The n reaches a minimum value of about 8 for clear Ge layer, whereas for GexSi1−x films, n is increased from 8 to 14. The presence of a thin strained film of the GexSi1−x caused not only the changes in critical thicknesses of the transitions, but also affected the properties of the germanium nanocluster array for the top Ge layer. Based on the RHEED data, the hut-like island form, which has not been previously observed by us between the hut and dome islands, has been detected. Data on the growth of Ge/GexSi1−x/Ge heterostructures with the uniform array of islands in the second layer of the Ge film have been received. PMID:23043796

  14. Phase transition on the Si(001) clean surface prepared in UHV MBE chamber: a study by high-resolution STM and in situ RHEED

    PubMed Central

    2011-01-01

    The Si(001) surface deoxidized by short annealing at T ~ 925°C in the ultrahigh vacuum molecuar beam epitaxy chamber has been in situ investigated using high-resolution scanning tunneling microscopy (STM)and redegreesected high-energy electron diffraction (RHEED. RHEED patterns corresponding to (2 × 1) and (4 × 4) structures were observed during sample treatment. The (4 × 4) reconstruction arose at T ≲ 600°C after annealing. The reconstruction was observed to be reversible: the (4 × 4) structure turned into the (2 × 1) one at T ≳ 600°C, the (4 × 4) structure appeared again at recurring cooling. The c(8 × 8) reconstruction was revealed by STM at room temperature on the same samples. A fraction of the surface area covered by the c(8 × 8) structure decreased, as the sample cooling rate was reduced. The (2 × 1) structure was observed on the surface free of the c(8 × 8) one. The c(8 × 8) structure has been evidenced to manifest itself as the (4 × 4) one in the RHEED patterns. A model of the c(8 × 8) structure formation has been built on the basis of the STM data. Origin of the high-order structure on the Si(001) surface and its connection with the epinucleation phenomenon are discussed. PACS 68.35.B-·68.37.Ef·68.49.Jk·68.47.Fg PMID:21711733

  15. Distinguishing cubic and hexagonal phases within InGaN/GaN microstructures using electron energy loss spectroscopy

    PubMed Central

    CHERNS, D; ALBERT, S.; BENGOECHEA‐ENCABO, A.; ANGEL SANCHEZ, M.; CALLEJA, E.; SCHIMPKE, T.; STRASSBURG, M.

    2015-01-01

    Summary 3D InGaN/GaN microstructures grown by metal organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) have been extensively studied using a range of electron microscopy techniques. The growth of material by MBE has led to the growth of cubic GaN material. The changes in these crystal phases has been investigated by Electron Energy Loss Spectroscopy, where the variations in the fine structure of the N K‐edge shows a clear difference allowing the mapping of the phases to take place. GaN layers grown for light emitting devices sometimes have cubic inclusions in the normally hexagonal wurtzite structures, which can influence the device electronic properties. Differences in the fine structure of the N K‐edge between cubic and hexagonal material in electron energy loss spectra are used to map cubic and hexagonal regions in a GaN/InGaN microcolumnar device. The method of mapping is explained, and the factors limiting spatial resolution are discussed. PMID:26366483

  16. Distinguishing cubic and hexagonal phases within InGaN/GaN microstructures using electron energy loss spectroscopy.

    PubMed

    Griffiths, I J; Cherns, D; Albert, S; Bengoechea-Encabo, A; Angel Sanchez, M; Calleja, E; Schimpke, T; Strassburg, M

    2016-05-01

    3D InGaN/GaN microstructures grown by metal organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) have been extensively studied using a range of electron microscopy techniques. The growth of material by MBE has led to the growth of cubic GaN material. The changes in these crystal phases has been investigated by Electron Energy Loss Spectroscopy, where the variations in the fine structure of the N K-edge shows a clear difference allowing the mapping of the phases to take place. GaN layers grown for light emitting devices sometimes have cubic inclusions in the normally hexagonal wurtzite structures, which can influence the device electronic properties. Differences in the fine structure of the N K-edge between cubic and hexagonal material in electron energy loss spectra are used to map cubic and hexagonal regions in a GaN/InGaN microcolumnar device. The method of mapping is explained, and the factors limiting spatial resolution are discussed. PMID:26366483

  17. Energy Performance Assessment of Radiant Cooling System through Modeling and Calibration at Component Level

    SciTech Connect

    Khan, Yasin; Mathur, Jyotirmay; Bhandari, Mahabir S

    2016-01-01

    The paper describes a case study of an information technology office building with a radiant cooling system and a conventional variable air volume (VAV) system installed side by side so that performancecan be compared. First, a 3D model of the building involving architecture, occupancy, and HVAC operation was developed in EnergyPlus, a simulation tool. Second, a different calibration methodology was applied to develop the base case for assessing the energy saving potential. This paper details the calibration of the whole building energy model to the component level, including lighting, equipment, and HVAC components such as chillers, pumps, cooling towers, fans, etc. Also a new methodology for the systematic selection of influence parameter has been developed for the calibration of a simulated model which requires large time for the execution. The error at the whole building level [measured in mean bias error (MBE)] is 0.2%, and the coefficient of variation of root mean square error (CvRMSE) is 3.2%. The total errors in HVAC at the hourly are MBE = 8.7% and CvRMSE = 23.9%, which meet the criteria of ASHRAE 14 (2002) for hourly calibration. Different suggestions have been pointed out to generalize the energy saving of radiant cooling system through the existing building system. So a base case model was developed by using the calibrated model for quantifying the energy saving potential of the radiant cooling system. It was found that a base case radiant cooling system integrated with DOAS can save 28% energy compared with the conventional VAV system.

  18. Comparison of Four Different Energy Balance Models for Estimating Evapotranspiration in the Midwest United States

    NASA Astrophysics Data System (ADS)

    Singh, R. K.; Senay, G. B.; Verdin, J. P.

    2015-12-01

    Availability of no-cost satellite images helped in development and utilization of remotely sensed images for water use estimation. Remotely sensed images are increasingly used for estimating evapotranspiration (ET) at different temporal and spatial scales. However, selecting any particular model from a plethora of energy balance models for estimating ET is challenging as each different model has its strengths and limitations. We compared four commonly used ET models, namely, Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC) model, Surface Energy Balance Algorithm for Land (SEBAL) model, Surface Energy Balance System (SEBS) model, and Operational Simplified Surface Energy Balance (SSEBop) model using Landsat images for estimating ET in the Midwest United States. We validated our model results using three AmeriFlux cropland sites at Mead, Nebraska. Our results showed that the METRIC and the SSEBop model worked very well at these sites with a root mean square error (RMSE) of less than 1 mm/day and an R2 of 0.96 (N=24). The mean bias error (MBE) was less than 10% for both the METRIC and the SSEBop models. In contrast, the SEBAL and the SEBS models have relatively higher RMSE (> 1.7 mm/day) and MBE (> 27%). However, all four models captured the spatial and temporal variation of ET reasonably well (R2 > 0.80). We found that the model simplification of the SSEBop for operational capability was not at the expense of model accuracy. Since the SSEBop model is relatively less data intensive and independent of user/automatic selection of anchor (hot/dry and cold/wet) pixels, it is more user friendly and operationally efficient. The SSEBop model can be reliably used for estimating water use using Landsat and MODIS images at daily, weekly, monthly, or annual time scale even in data scarce regions for sustainable use of limited water resources.

  19. Heavy Ion Fusion Accelerator Research (HIFAR) half-year report, October 1, 1989--March 31, 1990

    SciTech Connect

    Not Available

    1990-03-01

    This report discusses the following topics: Transverse Emittance Studies on MBE-4; MBE-4 Simulations; Beam Centroid Motion and Misalignments in MBE-4; Survey and Alignment of MBE-4; Energy Analysis of the 5mA MBE-4 Beam; An Improved 10 mA Ion Source for MBE-4; Emittance Degradation via a Wire Grid; Ion Source Development; 2 MV Injector; Electrostatic Quadrupole Prototype Development Activity; Magnetic Induction Core Studies; A Preliminary Consideration of Beam Splitting in Momentum Space; and Status of the Optimization Code HILDA.

  20. Effect of surface topography on reflection electron energy loss plasmon spectra of group III metals

    SciTech Connect

    Strawbridge, B.; Singh, R. K.; Beach, C.; Mahajan, S.; Newman, N.

    2006-09-15

    In situ reflection electron energy loss spectroscopy (REELS) and reflection high energy electron diffraction employing a 20 keV electron beam at a 2 deg. grazing angle were used to characterize the surface properties of molecular beam epitaxy (MBE) grown Al, Ga, and In metals on silicon and sapphire substrates. In our study we found that the surface topography strongly influences the REELS plasmon spectra. Smooth Al films with <1 nm rms roughness exhibited surface plasmon peaks. Both surface and bulk plasmons are seen from an Al film with a rms roughness of 3.5 nm. Aluminum surfaces with >5 nm rms roughness yielded only bulk plasmon peaks. To understand the EELS spectrum for the Ga and In films, the rms roughness alone is not the relevant figure of merit as the electron beam interaction with the surface is influenced most by the shape of the tops of the surface grains and the grain size. Indium films on Si with a rms roughness of 52 nm were found to excite predominantly surface plasmons as the grazing angle electron beam scattered mostly off the flat top surface of each grain and was not strongly influenced by the crevices between the grains. The rounded tops of the Ga topography with 31 nm rms roughness facilitated transmission through the grains and therefore excited a combination of bulk and surface plasmons. This experimental method is very surface sensitive, as a probe depth of 0.8 nm was inferred from the diminishing intensity of the substrate peak with increasing coverage of a flat metal surface. The techniques and methods discussed here can be readily applied to other thin film systems such as MBE-grown III-V semiconductors, sputtered oxides, and other vacuum deposited materials.

  1. Three dimensional simulations of space charge dominated heavy ion beams with applications to inertial fusion energy

    SciTech Connect

    Grote, D.P.

    1994-11-01

    Heavy ion fusion requires injection, transport and acceleration of high current beams. Detailed simulation of such beams requires fully self-consistent space charge fields and three dimensions. WARP3D, developed for this purpose, is a particle-in-cell plasma simulation code optimized to work within the framework of an accelerator`s lattice of accelerating, focusing, and bending elements. The code has been used to study several test problems and for simulations and design of experiments. Two applications are drift compression experiments on the MBE-4 facility at LBL and design of the electrostatic quadrupole injector for the proposed ILSE facility. With aggressive drift compression on MBE-4, anomalous emittance growth was observed. Simulations carried out to examine possible causes showed that essentially all the emittance growth is result of external forces on the beam and not of internal beam space-charge fields. Dominant external forces are the dodecapole component of focusing fields, the image forces on the surrounding pipe and conductors, and the octopole fields that result from the structure of the quadrupole focusing elements. Goal of the design of the electrostatic quadrupole injector is to produce a beam of as low emittance as possible. The simulations show that the dominant effects that increase the emittance are the nonlinear octopole fields and the energy effect (fields in the axial direction that are off-axis). Injectors were designed that minimized the beam envelope in order to reduce the effect of the nonlinear fields. Alterations to the quadrupole structure that reduce the nonlinear fields further were examined. Comparisons were done with a scaled experiment resulted in very good agreement.

  2. Low temperature grown photoconductive antennas for pulsed 1060 nm excitation: Influence of excess energy on the electron relaxation

    NASA Astrophysics Data System (ADS)

    Dietz, R. J. B.; Brahm, A.; Velauthapillai, A.; Wilms, A.; Lammers, C.; Globisch, B.; Koch, M.; Notni, G.; Tünnermann, A.; Göbel, T.; Schell, M.

    2015-01-01

    We investigate properties of MBE grown photoconductive terahertz (THz) antennas based on the InGaAs/InAlAs/InP material system aimed for an excitation wavelength of approx. 1060 nm. Therefore, we analyze several different approaches concerning growth parameters, layer and material compositions as well as doping. The carrier dynamics are probed via transient white-light pump-probe spectroscopy as well as THz Time Domain Spectroscopy (TDS) measurements. We find that the electron capture probability is reduced for higher electron energies. By adjusting the material band gap this can be resolved and lifetimes of 1.3 ps are obtained. These short lifetimes enable the detection of THz TDS spectra with a bandwidth exceeding 4 THz.

  3. A Reflection High Energy Electron Diffraction-Reflectance Anisotropy Spectroscopy Study of Silicon Growth Dynamics During Gas Source Molecular Beam Epitaxy from Silanes

    NASA Astrophysics Data System (ADS)

    Joyce, B. A.; Zhang, J.; Taylor, A. G.; Lees, A. K.

    Molecular beam epitaxy (MBE) provides an ideal experimental vehicle for the in situ study of thin film growth dynamics. By using a combination of reflection high energy electron diffraction (RHEED) and reflectance anisotropy (difference) spectroscopy [RA(D)S], it is possible to separate morphological (long range order) and local electronic structure effects, which we demonstrate with the growth of silicon films from disilane (Si2H6) on Si(001) (2 × 1)+(1 × 2) reconstructed surfaces. The rate-limiting step in Si growth from both monosilane (SiH4) and disilane is the desorption of molecular hydrogen and we have found using RAS that, over a significant range of temperature and coverage, hydrogen desorption follows zeroth order kinetics as the result of a step-mediated process. Finally, we show how this influences the growth rate on substrates of differing degrees of vicinality.

  4. MBE growth, structural and transport properties of alternately-strained ZnSSe/CdSe superlattices with effective band-gap 2.5-2.6 eV

    NASA Astrophysics Data System (ADS)

    Sorokin, S. V.; Gronin, S. V.; Evropeytsev, E. A.; Sedova, I. V.; Toropov, A. A.; Ivanov, S. V.

    2015-09-01

    Short-period ZnSySe1-y/CdSe superlattices (SLs) with an effective energy gap Eg=2.5-2.6 eV (T=300 K) are grown by molecular beam epitaxy pseudomorphically on GaAs (001), and their structural properties are studied by using X-ray diffraction (XRD) and transmission electron microscopy. Both sulfur content and thickness of the ZnSySe1-y SL barriers have been determined via analysis of the XRD curves, taking account of the thickness of the CdSe SL layers estimated independently from the low-temperature (T=77 K) PL spectra of the single CdSe quantum dot (QD) layer (nominal thickness of 2.8 monolayer) embedded into each SL. The evaluated SL parameters are shown to be in good agreement with the intended ones. The efficient non-equilibrium carrier transport in the SLs along the growth direction at 300 K is demonstrated by photoluminescence (PL) spectroscopy through the relative temperature variation of the intensities of the PL peaks originated from the buried CdSe/ZnSe QD layers and the ZnSSe/CdSe SLs.

  5. Room-temperature MBE deposition, thermoelectric properties, and advanced structural characterization of binary Bi[subscript 2]Te[subscript 3] and Sb[subscript 2]Te[subscript 3] thin films

    SciTech Connect

    Peranio, N.; Winkler, M.; Bessas, D.; Aabdin, Z.; König, J.; Böttner, H.; Hermann, R.P.; Eibl, O.

    2012-10-23

    Sb{sub 2}Te{sub 3} and Bi{sub 2}Te{sub 3} thin films were grown at room temperature on SiO{sub 2} and BaF{sub 2} substrates using molecular beam epitaxy. A layer-by-layer growth was achieved such that metallic layers of the elements with 0.2 nm thickness were deposited. The layer structure in the as-deposited films was confirmed by X-ray diffraction and was seen more clearly in Sb{sub 2}Te{sub 3} thin films. Subsequent annealing was done at 250 C for 2 h and produced the Sb{sub 2}Te{sub 3} and Bi{sub 2}Te{sub 3} crystal structure as confirmed by high-energy X-ray diffraction. This preparation process is referred to as nano-alloying and it was demonstrated to yield single-phase thin films of these compounds. In the thin films a significant texture could be identified with the crystal c axis being almost parallel to the growth direction for Sb{sub 2}Te{sub 3} and tilted by about 30{sup o} for Bi{sub 2}Te{sub 3} thin films. In-plane transport properties were measured for the annealed films at room temperature. Both films yielded a charge carrier density of about 2.6 x 10{sup 19} cm{sup -3}. The Sb{sub 2}Te{sub 3} films were p-type, had a thermopower of +130 {micro}V K{sup -1}, and surprisingly high mobilities of 402 cm{sup 2} V{sup -1} s{sup -1}. The Bi{sub 2}Te{sub 3} films were n-type, showed a thermopower of -153 {micro}V K{sup -1}, and yielded significantly smaller mobilities of 80 cm2 V{sup -1} s{sup -1}. The chemical composition and microstructure of the films were investigated by transmission electron microscopy (TEM) on cross sections of the thin films. The grain sizes were about 500 nm for the Sb{sub 2}Te{sub 3} and 250 nm for the Bi{sub 2}Te{sub 3} films. In the Bi{sub 2}Te{sub 3} thin film, energy-filtered TEM allowed to image a Bi-rich grain boundary phase, several nanometers thick. This secondary phase explains the poor mobilities of the Bi{sub 2}Te{sub 3} thin film. With these results the high potential of the nano-alloying deposition technique for

  6. MBE Growth of Graded Structures for Polarized Electron Emitters

    SciTech Connect

    Moy, Aaron; Maruyama, T.; Zhou, F.; Brachmann, A.

    2009-08-04

    SVT Associates, in collaboration with SLAC, has investigated two novel photocathode design concepts in an effort to increase polarization and quantum efficiency. AlGaAsSb/GaAs superlattice photocathodes were fabricated to explore the effect of antimony on device operation. In the second approach, an internal electrical field was created within the superlattice active layer by varying the aluminum composition in AlGaAs/GaAs. A 25% increase in quantum efficiency as a result of the gradient was observed.

  7. MBE Growth of GaAs Whiskers on Si Nanowires

    SciTech Connect

    Maxwell Andrews, Aaron

    2010-01-04

    We present the growth of GaAs nanowhiskers by molecular beam epitaxy on Si (111) nanowires grown by low-pressure chemical vapor deposition. The whiskers grow in the wurtzite phase, along the [0001] direction, on the {l_brace}112{r_brace} facets of the Si nanowire, forming a star-like six-fold radial symmetry. The photoluminescence shows a 30 meV blue shift with respect to bulk GaAs, additionally a GaAs/AlAs core-shell heterostructure shows increased luminescence.

  8. The Cleaning of Indium Phosphide Substrates for Growth by MBE

    NASA Astrophysics Data System (ADS)

    Hofstra, Peter

    1995-11-01

    A novel technique of using an in-situ ECR generated H-plasma to produce high quality surfaces on InP substrates, for growth of n-and p-type InP layers by GSMBE, has been investigated. The initial substrate surface quality determines the quality of the subsequently grown layers and therefore, the cleaning procedure is of critical importance. The standard approach entails a thermal desorption of a passivating oxide; however, this technique leaves carbon on the surface and, because oxides may vary in composition depending on the growth conditions, a consistent temperature for desorption may not be obtained. The desorption process is also dependent on the atmosphere in which it is carried out; i.e. whether an overpressure of P_2 or As _2 is used. Thermal desorption of oxides from InP requires the substrate to reach temperatures higher than normal GSMBE growth temperatures which can lead to substrate decomposition and, for regrowth applications, can alter dopant profiles and layer composition in ternary and quaternary layer growths. As an alternative, H-plasmas in separate vacuum chambers have been used to remove oxides from InP but this typically produces highly defective substrates due to a loss of phosphorus from the substrate. In this work the combination of an in-situ H-plasma with a stabilizing atmosphere of P_2 is used for the removal of oxides at temperatures equal to growth temperature and below. The mechanism involved in the thermal desorption of an oxide is first clarified and this procedure is compared with oxide removal by H-plasma etch in a phosphorus atmosphere. The ECR source can produce various plasma modes which have been thoroughly characterized. The effect of the different plasma conditions on clean InP is determined. These modes have different properties which result in different oxide etch rates. Various modes are compared and the mechanism of oxide removal is documented. As an alternative to oxide growth S-passivation has recently received attention as a surface passivation technique. Application of this surface, with and without H-plasma cleaning, has been investigated. The above treatments and other wet chemical surface treatments are compared to determine the optimal surface cleaning technique. The results indicate that thermal desorptions are driven by reaction with phosphorus from the substrate and therefore require high temperatures to promote significant phosphorus evaporation from the substrate. A H-plasma etch of the oxide is driven by the presence of atomic M in the plasma and results in the formation of water. Oxide removal rates were determine at various temperatures from 250^circC-490^ circC. The plasma etch was found to remove carbon contamination from the surface whereas, thermal desorptions do not. Defect levels in the underlying InP are sensitive to the plasma properties but with careful choice of plasma conditions defect states can be minimized. An optimal surface cleaning procedure has been developed which involves a UV-ozone treatment and H-plasma cleaning, resulting in interfaces free of electrically active defects in n -type material and a defect concentration of 8times10 ^{11} cm^{ -2} in p-type material.

  9. High growth speed of gallium nitride using ENABLE-MBE

    NASA Astrophysics Data System (ADS)

    Williams, J. J.; Fischer, A. M.; Williamson, T. L.; Gangam, S.; Faleev, N. N.; Hoffbauer, M. A.; Honsberg, C. B.

    2015-09-01

    Films of gallium nitride were grown at varying growth speeds, while all other major variables were held constant. Films grown determine the material impact of the high flux capabilities of the unique nitrogen plasma source ENABLE. Growth rates ranged from 13 to near 60 nm/min. X-ray ω scans of GaN (0002) have FWHM in all samples less than 300 arc sec. Cathodoluminescence shows radiative recombination for all samples at the band edge. In general material quality overall is high with slight degradation as growth speeds increase to higher rates.

  10. MBE-grown metamorphic lasers for applications at telecom wavelengths

    NASA Astrophysics Data System (ADS)

    Ledentsov, N. N.; Shchukin, V. A.; Kettler, T.; Posilovic, K.; Bimberg, D.; Karachinsky, L. Ya.; Gladyshev, A. Yu.; Maximov, M. V.; Novikov, I. I.; Shernyakov, Yu. M.; Zhukov, A. E.; Ustinov, V. M.; Kovsh, A. R.

    2007-04-01

    We have studied growth phenomena and structural and optical properties of metamorphic (MM) quantum dots (QDs) and QD lasers emitting in the 1.4-1.5 μm range. InAs/InGaAs QDs were grown on top of (In,Ga)As buffer layers deposited on GaAs (1 0 0) substrates. The wavelength of the QDs could be adjusted in the 1400-1600 nm spectral range by changing the composition of the (In,Ga)As matrix layer and by the amount of InAs deposited to form QDs. An additional wavelength shift can be achieved by strained-layer (In,Ga,Al)As overgrowth of the QDs. It is found that high-performance degradation-robust operation of the devices can be achieved through minimization of the defect density in the matrix material and within the QD sheets. A defect-reduction technique involving steps of strain-sensitive overgrowth and selective evaporation of the material in the defect-related areas was applied, leading to both elimination of dislocated clusters and blocking of propagating defects. MM QD lasers exhibited emission wavelength in the 1.4-1.5 μm range with a differential quantum efficiency of about ˜50% and pulsed power up to 7 W, limited by catastrophic optical mirror damage. The narrow-stripe lasers operate in a single transverse mode withstanding continuous wave current densities above 20 kA cm -2 without irreversible degradation. A maximum single mode continuous-wave output power of 220 mW limited by thermal roll-over is obtained. No beam filamentation was observed up to the highest pumping levels. Single-mode devices with as-cleaved facets are tested for 60 °C (800 h) and 70 °C (200 h) junction temperature. No noticeable degradation has been observed at 50 mW cw single mode output power, clearly manifesting for the first time degradation-free laser diodes on foreign substrates. The technology opens a way for integration of various III-V materials with silicon or germanium substrates for the next generation of microprocessors, optical interconnects and cascaded solar cells.

  11. MBE growth of GaP on a Si substrate

    SciTech Connect

    Sobolev, M. S. Lazarenko, A. A.; Nikitina, E. V.; Pirogov, E. V.; Gudovskikh, A. S.; Egorov, A. Yu.

    2015-04-15

    It is shown that single-crystal GaP buffer layers can be formed on a Si substrate by molecular-beam epitaxy, with the “migration-enhanced epitaxy” procedure applied in the stage in which the nucleating layer is formed. When a GaP layer is produced on a p-type silicon substrate, a p-n junction is created in a natural way between the p-Si substrate and the surface n-Si layer produced by the diffusion of phosphorus into the substrate during the course of the epitaxial growth of GaP. This p-n junction can be used as the first junction of a silicon-based multijunction photovoltaic converter.

  12. Native defects in MBE-grown CdTe

    SciTech Connect

    Olender, Karolina; Wosinski, Tadeusz; Makosa, Andrzej; Tkaczyk, Zbigniew; Kolkovsky, Valery; Karczewski, Grzegorz

    2013-12-04

    Deep-level traps in both n- and p-type CdTe layers, grown by molecular-beam epitaxy on GaAs substrates, have been investigated by means of deep-level transient spectroscopy (DLTS). Four of the traps revealed in the DLTS spectra, which displayed exponential kinetics for capture of charge carriers into the trap states, have been assigned to native point defects: Cd interstitial, Cd vacancy, Te antisite defect and a complex formed of the Te antisite and Cd vacancy. Three further traps, displaying logarithmic capture kinetics, have been ascribed to electron states of treading dislocations generated at the mismatched interface with the substrate and propagated through the CdTe layer.

  13. InP based QCL in MBE production machine

    NASA Astrophysics Data System (ADS)

    Garcia, Michel; Vermersch, Francois Julien; Marcadet, Xavier; Bansropun, Shailendra; Carras, Mathieu; Wilk, Arnaud; Chaix, Christine; Sirtori, Carlo

    2006-02-01

    Quantum Cascade Lasers (QCL), emitting between 5 and 9 μm, have been realised with a view to achieving QCLs fabrication on a production scale. The growth of the structures was carried out in a multi-wafer RIBER 49 system (13 x 2" platen), and the processing sequence involved an Inductively Coupled Plasma (ICP) step for homogeneity and reproducibility purposes. To validate the approach used, a first batch of lasers, emitting around 9μm, based on a design already published [1], has been realised. State of the art performance on these devices (J th = 4.2 kA cm -2, η = 304 mW A -1, P max = 690 mW) has been achieved. A second set of strained balanced structures, emitting around 5.4μm, has been demonstrated, working in pulsed operation at room temperature(J th = 3.9 kA cm -2, η = 362 mW A -1, P max = 420 mW).

  14. MBE Growth of Graded Structures for Polarized Electron Emitters

    SciTech Connect

    Not Available

    2010-08-25

    SVT Associates, in collaboration with SLAC, have investigated two novel photocathode design concepts in an effort to increase polarization and quantum efficiency. AlGaAsSb/GaAs superlattice photocathodes were fabricated to explore the effect of antimony on device operation. In the second approach, an internal electrical field was created within the superlattice active layer by varying the aluminum composition in AlGaAs/GaAs. A 25% increase in quantum efficiency as a result of the gradient was observed.

  15. Program plan for the MBE-4 multiple beam experiment

    SciTech Connect

    Avery, R.T.

    1985-02-01

    The technical description treats the arrangement of the Injector System (made up of an existing High Voltage Marx Generator, a new Four-beam Source array and a Beam Conditioning Unit for matching and steering) and the Accelerator Apparatus which contains the 24 shaped-pulsed accelerating units. Flexibility in diagnostic capability and physics experiments has been maintained insofar as possible.

  16. Progress in MBE grown type-II superlattice photodiodes

    NASA Technical Reports Server (NTRS)

    Hill, Cory J.; Li, Jian V.; Mumolo, Jason M.; Gunapala, Sarath D.

    2006-01-01

    We report on the status of GaSb/InAs type-II superlattice diodes grown and fabricated at the Jet Propulsion Laboratory designed for infrared absorption in the 8-12(mu)m range. Recent devices have produced detectivities as high as 8x10 to the tenth power Jones with a differential resistance-area product greater than 6 Ohmcm(sup 2) at 80K with a long wavelength cutoff of approximately 12(mu)m. The measured quantum efficiency of these front-side illuminated devices is close to 30% in the 10-11(mu)m range without antireflection coatings.

  17. Feasibility study to develop a marketing plan and strategy for increasing the participation of minority business enterprises and black colleges and universities in energy-related industries

    SciTech Connect

    Not Available

    1983-01-31

    This study was designed to identify and test an alternative method for more effective means of involving Minority Business Enterprises (MBEs) and historically Black colleges and universities (HBCUs) in energy-related business opportunities. Based upon the analysis of MBE and HBCU technical assistance programs, DOD's, DOE's, and TVA's procurement processes and the results of the test used to validate the adaptability of a performance tested alternative marketing system to energy-related industries. Based on the findings and conclusions of this study and in order to meet the objectives of: (1) increasing participation of MBEs and HBCUs in TVA and energy-related industries; (2) ensuring that the statutory objectives of Title VI of the Civil Rights Act of 1964 and Public Law 95-507 are achieved in the public and private energy market sectors; and (3) meeting President Reagan's goal of realizing $22 billion in minority contracts within the next three years, BTW recommends that the Portfolio System be adapted, demonstrated, installed and deployed in large-scale, complex, energy-related research and development facilities and power utilities' procurement programs.

  18. Solar energy resources at South region of Brazil

    NASA Astrophysics Data System (ADS)

    Vinicius Fiorin, Daniel; Schuch, Nelson Jorge; Ramos Martins, Fernando; Bueno Pereira, Enio; Ceconi, Marcio; Brackmann, Rodrigo; Guarnieri, Ricardo André

    The Center for Weather Forecast and Climate Studies at the Brazilian National Institute for Space Research, Ministry of Science and Technology - CPTEC/INP-MCT, have installed throughout Brazilian territory several sites to acquired solar irradiation data used to assess the renewable energy potential of Brazil as part of SONDA project (www.cptec.inpe.br/sonda/). One of ground sites is located at the Southern Space Observatory-SSO/CRS/CIE/INPE-MCT, (29o S; 53o W), in São Martinho da Serra, RS, South of Brazil, where diffuse and global solar a irradiation are measured by CM 22 and CM21 Pyrhanometers), direct solar radiation are measured by Pyrheliometer NIP and opaque and thin cloudiness fractions were esteemed by a Total Sky Imager TSI-440 (YES, Inc). Our concern is with the fact that the current world energy scenery, characterized by petroleum sources exhaustion and environmental concerns, point out to the use of clean and renewable energy sources such as the solar energy. This work aims to the evaluation of the solar energy resource by using stochastic models relating the cloud cover fraction and solar radiation parameters such as diffuse-to-direct-beam ratio (DDB), diffuse-toglobal solar irradiation ratio (K), diffuse-to-TOA irradiation ratio (KD ), and global-to-TOA irradiation ratio (KT ), measured with the SONDA Project, where TOA is the total irradiation that reach the atmosphere. Only data collected for zenithal solar angle (SZA) lesser than 75 deg for the period between September/2005 to September/2007 were used. The ground data were averaged for fifteen minutes intervals in order to reduce the influence of high frequency variability of cloud cover. It was observed low correlation (around 0.55) among the diffuse to TOA irradiation ratio and cloud cover. Better correlation (about 0.94) were obtained for K parameter. The statistic deviations RMSE (23-28%) and MBE (0.3-5%) were calculated to validate and compare the models performance. The results showed more

  19. Energy 101: Geothermal Energy

    SciTech Connect

    2014-05-27

    See how we can generate clean, renewable energy from hot water sources deep beneath the Earth's surface. The video highlights the basic principles at work in geothermal energy production, and illustrates three different ways the Earth's heat can be converted into electricity.

  20. Energy 101: Geothermal Energy

    ScienceCinema

    None

    2014-06-23

    See how we can generate clean, renewable energy from hot water sources deep beneath the Earth's surface. The video highlights the basic principles at work in geothermal energy production, and illustrates three different ways the Earth's heat can be converted into electricity.

  1. Feasibility study to develop a marketing plan and strategy for increasing the participation of minority business enterprises and black colleges and universities in energy-related industries. Final report

    SciTech Connect

    Not Available

    1983-01-31

    This study was designed to identify and test an alternative method for more effective means of involving Minority Business Enterprises (MBEs) and historically Black colleges and universities (HBUs) in energy-related business opportunities. Based upon the analysis of MBE and HBCU technical assistance programs, DOD's DOE's, and TVA's procurement processes and the results of the test used to validate the adaptability of a performance tested alternative marketing system to energy-related industries. Based on the findings and conclusions of this study and in order to meet the objectives of: (1) increasing participation of MBEs and HBCUs in TVA and energy-related industries; (2) ensuring that the statutory objectives of Title VI of the Civil Rights Act of 1964 and Public Law 95-507 are achieved in the public and private energy market sectors; and (3) meeting President Reagan's goal of realizing $22 billion in minority contracts within the next three years, BTW recommends that the Portfolio System be adapted, demonstrated, installed and deployed in large-scale, complex, energy-related research and development facilities and power utilities' procurement programs.

  2. Heavy Ion Fusion Accelerator Research (HIFAR) year-end report, April 1, 1986-September 30, 1986

    SciTech Connect

    Not Available

    1986-10-01

    Activities are reported on MBE-4, the four-beam proof-of-principle ion induction linear accelerator with the capability of beam-current amplification. Mechanical aspects of MBE-4, quadrupole insulator performance, and pulsers are discussed. The computer code, SLID, has been used to help understand the longitudinal beam dynamics in MBE-4. A computer-controlled emittance scanning system is in use in MBE-4. A systematic effort is under way to discover and correct all the defects peculiar to the low energy part of the linac design code. (LEW)

  3. Energy: Conservation, Energy Briefs

    ERIC Educational Resources Information Center

    Nation's Schools and Colleges, 1975

    1975-01-01

    A comprehensive energy conservation program at College of the Holy Cross has saved nearly one-third of the fuel oil and one-fifth of the electricity used at the college; briefs on boilers, lights, design. (Author/MLF)

  4. Energy Technology.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Reviewed are technological problems faced in energy production including locating, recovering, developing, storing, and distributing energy in clean, convenient, economical, and environmentally satisfactory manners. The energy resources of coal, oil, natural gas, hydroelectric power, nuclear energy, solar energy, geothermal energy, winds, tides,…

  5. Correlation between the quantized energies and the photovoltaic spectra for a GaAs/AlGaAs quantum well structure

    SciTech Connect

    Russo, O.L.; Rehn, V.; Nee, T.W.; Dumas, K.A.

    1996-12-31

    The authors have measured the photovoltaic spectra at 300K for a PIN GaAs/AlGaAs structure containing five coupled wells (50A/28A) grown by molecular beam epitaxy (MBE). The spectra were obtained in the energy range from 1.40 eV to 1.60 eV. This is the region in which optical transitions between the sub-band valence and conduction states are possible. Five direct optical transitions are allowed for this structure. These transitions are normally difficult to measure at room temperature because of broadening, nevertheless, some of the allowed transitions were observed from the photovoltaic spectra and agreed with calculations. The authors have previously shown that measurements made using electroreflectance (ER) agree with these results. However, with ER, three possible transitions were observed but only one with certainty, possibly because of interference caused by adjacent line spectra interaction. This interference appears to be less pronounced in the photovoltaic spectra, which aids in the identification of transitions.

  6. Energy Auditing.

    ERIC Educational Resources Information Center

    Association of Energy Engineers, Atlanta, GA.

    Presented is a discussion of various aspects of policy and implementation of energy auditing at various levels of government. Included are 11 chapters dealing with: (1) a national energy plan, (2) state certification for energy auditors, (3) survey instrumentation, (4) energy management economics, (5) Maine school energy auditing, (6) energy…

  7. Solar Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  8. Energy Drinks

    MedlinePlus

    ... R S T U V W X Y Z Energy Drinks Share: © Thinkstock Energy drinks are widely promoted as products that increase ... people has been quite effective. Next to multivitamins, energy drinks are the most popular dietary supplement consumed ...

  9. Energy overview

    NASA Technical Reports Server (NTRS)

    Slone, H. O.

    1980-01-01

    The experience, capabilities, and facilities being utilized at NASA Lewis in support of energy programs conducted by the Department of Energy and other agencies are discussed. Background information is given regarding NASA's involvement in solving energy problems.

  10. Energy Models

    EPA Science Inventory

    Energy models characterize the energy system, its evolution, and its interactions with the broader economy. The energy system consists of primary resources, including both fossil fuels and renewables; power plants, refineries, and other technologies to process and convert these r...

  11. Energy resources

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A statistical analysis of the availability of fossil fuels for energy and non-energy production is presented. The cumulative requirements for petroleum, natural gas, and coal are discussed. Alternate forms of energy are described and the advantages and limitations are analyzed. Emphasis is placed on solar energy availability and methods for conversion. The Federal energy research and development funding for energy sources is tabulated.

  12. Energy Theater

    NASA Astrophysics Data System (ADS)

    Daane, Abigail R.; Wells, Lindsay; Scherr, Rachel E.

    2014-05-01

    Energy Theater is a dynamic, full-body activity that engages all students in representing the flow of energy in various phenomena, such as a light bulb burning steadily or a refrigerator cooling food. In Energy Theater, each participant acts as a unit of energy that has one form at a time. Regions on the floor correspond to objects in a physical scenario, and participants move from one region to another to demonstrate the flow of energy among objects. (See Figs. 1, 3, and 4.) The goal of Energy Theater is for students to track energy transfers and transformations in real-world energy scenarios while employing the principle of energy conservation and disambiguating matter and energy. Unlike most representations of energy, which are static before-and-after accounting schemes for energy changes, Energy Theater is a dynamic representation that provides a natural stepping stone toward the more advanced ideas of energy density, energy current, and a continuity equation relating them. The fact that conservation of energy is embedded in the representation encourages students to "find the energy" in situations where it may be imperceptible. The rules of Energy Theater are listed in Fig. 2.

  13. The Study of Energy Band Gap of Al{sub x}In{sub y}Ga{sub 1-x-y}N Quaternary Alloys Using UV-VIS Spectroscopy

    SciTech Connect

    Abid, M. A.; Hassan, H. Abu; Hassan, Z.; Ng, S. S.; Raof, N. H. Abd.; Bakhori, S. K. Mohd

    2010-07-07

    Optical characterizations have been performed on high-quality quaternary Al{sub x}In{sub y}Ga{sub 1-x-y}N thin films using UV-VIS spectroscopy at room temperature. The Al{sub x}In{sub y}Ga{sub 1-x-y}N films were grown on c-plane (0001) sapphire substrates with AlN as buffer layers using molecular beam epitaxy (MBE) technique with aluminum (Al) mole fraction x ranging from 0.0 to 0.2 and constant indium (In) mole fraction y = 0.1. The UV-VIS measurements indicated that the energy band gap of the quaternary films increases with increasing Al composition from 0.05 to 0.2. This trend is expected since the incorporation of Al increases the energy band gap of ternary In0.1Ga0.90N (3.004eV). We have also investigated the bowing parameter of the variation of energy band gaps and found it to be very sensitive on Al content. A value of b=7 eV has been obtained for our quaternary Al{sub x}In{sub y}Ga{sub 1-x-y}N alloys.

  14. Geothermal Energy.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    An introduction to geothermal energy is provided in this discussion of: (1) how a geothermal reservoir works; (2) how to find geothermal energy; (3) where it is located; (4) electric power generation using geothermal energy; (5) use of geothermal energy as a direct source of heat; (6) geopressured reservoirs; (7) environmental effects; (8)…

  15. Geothermal Energy.

    ERIC Educational Resources Information Center

    Nemzer, Marilyn; Page, Deborah

    This curriculum unit describes geothermal energy in the context of the world's energy needs. It addresses renewable and nonrenewable energy sources with an in-depth study of geothermal energy--its geology, its history, and its many uses. Included are integrated activities involving science, as well as math, social studies, and language arts.…

  16. Energy Theater

    ERIC Educational Resources Information Center

    Daane, Abigail R.; Wells, Lindsay; Scherr, Rachel E.

    2014-01-01

    Energy Theater is a dynamic, full-body activity that engages all students in representing the flow of energy in various phenomena, such as a light bulb burning steadily or a refrigerator cooling food. In Energy Theater, each participant acts as a unit of energy that has one form at a time. Regions on the floor correspond to objects in a physical…

  17. Energy Consumption vs. Energy Requirement

    ERIC Educational Resources Information Center

    Fan, L. T.; Zhang, Tengyan; Schlup, John R.

    2006-01-01

    Energy is necessary for any phenomenon to occur or any process to proceed. Nevertheless, energy is never consumed; instead, it is conserved. What is consumed is available energy, or exergy, accompanied by an increase in entropy. Obviously, the terminology, "energy consumption" is indeed a misnomer although it is ubiquitous in the…

  18. Energy Conservation vs. Energy Efficiency

    SciTech Connect

    Somasundaram, Sriram

    2010-09-30

    Energy conservation is considered by some as synonymous with energy efficiency, but to others, it has a meaning of getting fewer or lower quality energy services. The degree of confusion between these meanings varies widely by individual, culture, historic period and language spoken. In the context of this document, energy conservation means to keep from being lost or wasted; saved, and energy efficiency means the ability to produce a desired effect or product with a minimum of effort, expense or waste.

  19. Energy Analysis.

    ERIC Educational Resources Information Center

    Bazjanac, Vladimir

    1981-01-01

    The Aquatic Center at Corvallis (Oregon) is analyzed for energy use. Energy conservation in the building would be accomplished best through heavy insulation of exterior surfaces and the maximization of passive solar gain. (Author/MLF)

  20. Save Energy $.

    ERIC Educational Resources Information Center

    Hirsch, Thomas E., III; Shapiro, Robert F.

    1986-01-01

    Large institutional energy users can reduce energy costs by constructing and operating steam and electricity cogeneration facilities and purchasing their own gas at lower prices rather than relying on local distributors. (MSE)

  1. Geothermal Energy

    SciTech Connect

    Steele, B.C.; Harman, G.; Pitsenbarger, J.

    1996-02-01

    Geothermal Energy Technology (GET) announces on a bimonthly basis the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production.

  2. Geothermal Energy.

    ERIC Educational Resources Information Center

    Reed, Marshall J.

    1979-01-01

    During 1978, exploration for geothermal energy continued at the same moderately low level of the past few years in most countries. The U.S. is the only country where the development of geothermal energy depends on private industry. (BB)

  3. Hydrogen energy.

    PubMed

    Edwards, P P; Kuznetsov, V L; David, W I F

    2007-04-15

    The problem of anthropogenically driven climate change and its inextricable link to our global society's present and future energy needs are arguably the greatest challenge facing our planet. Hydrogen is now widely regarded as one key element of a potential energy solution for the twenty-first century, capable of assisting in issues of environmental emissions, sustainability and energy security. Hydrogen has the potential to provide for energy in transportation, distributed heat and power generation and energy storage systems with little or no impact on the environment, both locally and globally. However, any transition from a carbon-based (fossil fuel) energy system to a hydrogen-based economy involves significant scientific, technological and socio-economic barriers. This brief report aims to outline the basis of the growing worldwide interest in hydrogen energy and examines some of the important issues relating to the future development of hydrogen as an energy vector. PMID:17272235

  4. Energy Storage.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Described are technological considerations affecting storage of energy, particularly electrical energy. The background and present status of energy storage by batteries, water storage, compressed air storage, flywheels, magnetic storage, hydrogen storage, and thermal storage are discussed followed by a review of development trends. Included are…

  5. Dark energy

    NASA Astrophysics Data System (ADS)

    Linder, Eric

    2008-02-01

    Dark energy is the name given to the unknown physics causing the current acceleration of the cosmic expansion. Whether dark energy is truly a new component of energy density or an extension of gravitational physics beyond general relativity is not yet known. From: Mattia Galiazzo Address: mattia.galiazzo@univie.ac.at Database: ast

  6. Geothermal Energy

    SciTech Connect

    Steele, B.C.; Pichiarella, L.S.; Kane, L.S.; Henline, D.M.

    1995-01-01

    Geothermal Energy (GET) announces on a bimonthly basis the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past two months.

  7. ENERGY-10

    Energy Science and Technology Software Center (ESTSC)

    1996-06-30

    ENERGY-10 is a software tool that helps architects, builders, and engineers quickly identify the most cost-effective, energy-saving measures to take in designing a low-energy building. The simulation software is suitable for examining small commercial and residential buildings that are characterized by one, or two thermal zones (generally less than 10,000 ft2.)

  8. Geothermal Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Described are the origin and nature of geothermal energy. Included is the history of its development as an energy source, technological considerations affecting its development as an energy source, its environmental effects, economic considerations, and future prospects of development in this field. Basic system diagrams of the operation of a…

  9. Energy Builders.

    ERIC Educational Resources Information Center

    Instructor, 1982

    1982-01-01

    Due to increasing energy demands and decreasing supplies, it is important for teachers to provide students with a solid foundation for energy decision making. Activities are presented which offer hands-on experiences with four sources of energy: wind, water, sun, and fossil fuels. (JN)

  10. Energy Digest.

    ERIC Educational Resources Information Center

    Gaddy, Carol T., Ed.; Wells, Kathy, Ed.

    This collection of reprints offers practical solutions, not readily available elsewhere, to everyday energy problems, such as high utility bills, insulating windows, getting more gas mileage, or buying a more efficient washer or refrigerator. The Arkansas Energy Office provides a weekly column of energy news and conservation tips to newspapers,…

  11. Biomass energy

    SciTech Connect

    Smil, V.

    1983-01-01

    This book offers a broad, interdisciplinary approach to assessing the factors that are key determinants to the use of biomass energies, stressing their limitations, complexities, uncertainties, links, and consequences. Considers photosynthesis, energy costs of nutrients, problems with monoculture, and the energy analysis of intensive tree plantations. Subjects are examined in terms of environmental and economic impact. Emphasizes the use and abuse of biomass energies in China, India, and Brazil. Topics include forests, trees for energy, crop residues, fuel crops, aquatic plants, and animal and human wastes. Recommended for environmental engineers and planners, and those involved in ecology, systematics, and forestry.

  12. Energy catastrophes and energy consumption

    SciTech Connect

    Davis, G. )

    1991-01-01

    The possibility of energy catastrophes in the production of energy serves to make estimation of the true social costs of energy production difficult. As a result, there is a distinct possibility that the private marginal cost curve of energy producers lies to the left or right of the true cost curve. If so, social welfare will not be maximized, and underconsumption or overconsumption of fuels will exist. The occurrence of energy catastrophes and observance of the market reaction to these occurrences indicates that overconsumption of energy has been the case in the past. Postulations as to market reactions to further energy catastrophes lead to the presumption that energy consumption levels remain above those that are socially optimal.

  13. Energy 101: Home Energy Assessment

    ScienceCinema

    None

    2013-05-29

    A home energy checkup helps owners determine where their house is losing energy and money - and how such problems can be corrected to make the home more energy efficient. A professional technician - often called an energy auditor - can give your home a checkup. You can also do some of the steps yourself. Items shown here include checking for leaks, examining insulation, inspecting the furnace and ductwork, performing a blower door test and using an infrared camera.

  14. Energy 101: Home Energy Assessment

    SciTech Connect

    2010-01-01

    A home energy checkup helps owners determine where their house is losing energy and money - and how such problems can be corrected to make the home more energy efficient. A professional technician - often called an energy auditor - can give your home a checkup. You can also do some of the steps yourself. Items shown here include checking for leaks, examining insulation, inspecting the furnace and ductwork, performing a blower door test and using an infrared camera.

  15. Energy Audits. Energy Technology Series.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This course in energy audits is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in company-sponsored training…

  16. Wind energy.

    PubMed

    Leithead, W E

    2007-04-15

    From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented. PMID:17272245

  17. Energy storage

    NASA Astrophysics Data System (ADS)

    Kaier, U.

    1981-04-01

    Developments in the area of energy storage are characterized, with respect to theory and laboratory, by an emergence of novel concepts and technologies for storing electric energy and heat. However, there are no new commercial devices on the market. New storage batteries as basis for a wider introduction of electric cars, and latent heat storage devices, as an aid for solar technology applications, with satisfactory performance standards are not yet commercially available. Devices for the intermediate storage of electric energy for solar electric-energy systems, and for satisfying peak-load current demands in the case of public utility companies are considered. In spite of many promising novel developments, there is yet no practical alternative to the lead-acid storage battery. Attention is given to central heat storage for systems transporting heat energy, small-scale heat storage installations, and large-scale technical energy-storage systems.

  18. Transporation Energy

    SciTech Connect

    Clifford Mirman; Promod Vohra

    2012-06-30

    This Transportation Energy Project is comprised of four unique tasks which work within the railroad industry to provide solutions in various areas of energy conservation. These tasks addressed: energy reducing yard related decision issues; alternate fuels; energy education, and energy storage for railroad applications. The NIU Engineering and Technology research team examined these areas and provided current solutions which can be used to both provide important reduction in energy usage and system efficiency in the given industry. This project also sought a mode in which rural and long-distance education could be provided. The information developed in each of the project tasks can be applied to all of the rail companies to assist in developing efficiencies.

  19. Nuclear energy.

    PubMed

    Grandin, Karl; Jagers, Peter; Kullander, Sven

    2010-01-01

    Nuclear energy can play a role in carbon free production of electrical energy, thus making it interesting for tomorrow's energy mix. However, several issues have to be addressed. In fission technology, the design of so-called fourth generation reactors show great promise, in particular in addressing materials efficiency and safety issues. If successfully developed, such reactors may have an important and sustainable part in future energy production. Working fusion reactors may be even more materials efficient and environmental friendly, but also need more development and research. The roadmap for development of fourth generation fission and fusion reactors, therefore, asks for attention and research in these fields must be strengthened. PMID:20873683

  20. Solar energy

    NASA Technical Reports Server (NTRS)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  1. Magma energy

    SciTech Connect

    Dunn, J.C.

    1987-01-01

    The thermal energy contained in magmatic systems represents a huge potential resource. In the US, useful energy contained in molten and partially-molten magma within the upper 10 km of the crust has been estimated at 5 to 50 x 10/sup 22/ J (50,000 to 500,000 Quads). The objective of the Magma Energy Extraction Program is to determine the engineering feasibility of locating, accessing, and utilizing magma as a viable energy resource. This program follows the DOE/OBES-funded Magma Energy Research Project that concluded scientific feasibility of the magma energy concept. A primary long-range goal of this program is to conduct an energy extraction experiment directly in a molten, crustal magma body. Critical to determining engineering feasibility are several key technology tasks: (1) Geophysics - to obtain detailed definition of potential magma targets, (2) Geochemistry/Materials - to characterize the magma environment and select compatible engineering materials, (3) Drilling - to develop drilling and completion techniques for entry into a magma body, and (4) Energy Extraction - to develop heat extraction technology.

  2. Energy Solutions

    ERIC Educational Resources Information Center

    Sobieski, Jeff

    2010-01-01

    Education facilities managers are faced with a daunting set of challenges: They must find new ways to reduce energy consumption and carry out greener energy policies. HVAC typically accounts for more than 30% of a building's electricity costs, so there is a clear incentive to eliminate unnecessary heating and cooling of unoccupied rooms. With more…

  3. Energy Underground.

    ERIC Educational Resources Information Center

    Wiley, Catherina L.

    2003-01-01

    Describes a unit to study the cycling of matter and energy through speleology using cooperative learning groups. Integrates the topic with zoology, biogeochemistry, paleontology, and meteorology. Includes a sample rubric for a salt block cave presentation, unit outline, and processes for studying matter and energy processes in caves. (Author/KHR)

  4. Geothermal Energy.

    ERIC Educational Resources Information Center

    Bufe, Charles Glenn

    1983-01-01

    Major activities, programs, and conferences in geothermal energy during 1982 are highlighted. These include first comprehensive national assessment of U.S. low-temperature geothermal resources (conducted by U.S. Geological Survey and Department of Energy), map production by U.S. Geological Survey, geothermal plant production, and others. (JN)

  5. Energy Adventure.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Designed as an interdisciplinary, supplemental teaching guide, this document provides fundamental information about energy supply, use, and conservation and related learning activities for secondary students. Eight units address the following topics: energy history, petroleum, natural gas, coal, electricity, alternative sources, energy…

  6. Energy Demands

    ERIC Educational Resources Information Center

    Wilkinson, Ron

    2010-01-01

    When construction slows and campus operating expenses are under the microscope, it is more important than ever to save energy dollars with the equipment and staff on hand. For the facilities manager who thinks out of the box, significant savings can be found on most school and college campuses. This article provides energy-conservation tips that…

  7. Energy - 1977.

    ERIC Educational Resources Information Center

    Kansas State Board of Regents, Topeka.

    A checklist of energy consumption reduction measures for universities is provided with the intent of achieving rapid and significant energy savings at minimal cost. Measures described should be within the scope of accomplishment by regular university operating and maintenance personnel. The measures involve non-technical actions such as adjusting…

  8. Renewable Energy

    NASA Astrophysics Data System (ADS)

    Boyle, Godfrey

    2004-05-01

    Stimulated by recent technological developments and increasing concern over the sustainability and environmental impact of conventional fuel usage, the prospect of producing clean, sustainable power in substantial quantities from renewable energy sources arouses interest around the world. This book provides a comprehensive overview of the principal types of renewable energy--including solar, thermal, photovoltaics, bioenergy, hydro, tidal, wind, wave, and geothermal. In addition, it explains the underlying physical and technological principles of renewable energy and examines the environmental impact and prospects of different energy sources. With more than 350 detailed illustrations, more than 50 tables of data, and a wide range of case studies, Renewable Energy, 2/e is an ideal choice for undergraduate courses in energy, sustainable development, and environmental science. New to the Second Edition ·Full-color design ·Updated to reflect developments in technology, policy, attitides ·Complemented by Energy Systems and Sustainability edited by Godfrey Boyle, Bob Everett and Janet Ramage, all of the Open University, U.K.

  9. Energy Control Systems: Energy Savings.

    ERIC Educational Resources Information Center

    School Business Affairs, 1980

    1980-01-01

    The installation of proper control systems is estimated as saving up to 25 percent of the energy used in schools. Other potential energy-saving areas are transmission (heat loss or gain through walls, especially ceilings); internal load (heat from students, lights, and machinery); ventilation; and equipment maintenance. (Author/MLF)

  10. Energy generator

    SciTech Connect

    Krisko, P.

    1989-08-01

    The patent describes a power booster. It comprises: at least one pendulum means suspended at one end to oscillate about the point of suspension; power generating means; mass means connected to one end of the pendulum means; spring means disposed in operative cooperation with the mass means to impart energy into the pendulum means and assist the pendulum means in oscillating about the point of suspension; and energy transfer linkage means between the pendulum means and the power generating means for transferring energy between the pendulum means and the power generating means.

  11. Solar Energy

    ERIC Educational Resources Information Center

    Building Design and Construction, 1977

    1977-01-01

    Describes 21 completed projects now using solar energy for heating, cooling, or electricity. Included are elementary schools in Atlanta and San Diego, a technical school in Detroit, and Trinity University in San Antonio, Texas. (MLF)

  12. Energy conversion

    SciTech Connect

    Woodall, J.M.

    1982-02-16

    Energy conversion capable of receiving input energy in thermal or radiant form at a variable rate and releasing energy in thermal, radiant or electrical form independent of rate is accomplished by providing a buffer member of a material that has three criteria: a melting temperature above 1300/sup degree/ K, a thermal conductance greater than 0.1 in calories per square centimeter per centimeter per degree per second and a latent heat of fusion of the order of 1 kilocalorie per mole. The converter can absorb energy of multiple types, store it and then release it in a form compatible with the prospective use. Sunlight of daylight duration and varying intensity is converted to steady 24 hour a day electrical output.

  13. Salinity Energy.

    ERIC Educational Resources Information Center

    Schmitt, Walter R.

    1987-01-01

    Discussed are the costs of deriving energy from the earth's natural reserves of salt. Argues that, as fossil fuel supplies become more depleted in the future, the environmental advantages of salinity power may prove to warrant its exploitation. (TW)

  14. Tidal Energy.

    ERIC Educational Resources Information Center

    Impact of Science on Society, 1987

    1987-01-01

    States that tidal power projects are feasible in a relatively limited number of locations around the world. Claims that together they could theoretically produce the energy equivalent to more than one million barrels of oil per year. (TW)

  15. Energy Bingo.

    ERIC Educational Resources Information Center

    Canipe, Stephen

    Rules are provided for this bingo game focusing on terms related to solar, coal, nuclear, hydro, and wind energy. Playing cards and calling cards (to be cut out by the teacher) are also provided. (JN)

  16. Energy Storage

    SciTech Connect

    Mukundan, Rangachary

    2014-09-30

    Energy storage technology is critical if the U.S. is to achieve more than 25% penetration of renewable electrical energy, given the intermittency of wind and solar. Energy density is a critical parameter in the economic viability of any energy storage system with liquid fuels being 10 to 100 times better than batteries. However, the economical conversion of electricity to fuel still presents significant technical challenges. This project addressed these challenges by focusing on a specific approach: efficient processes to convert electricity, water and nitrogen to ammonia. Ammonia has many attributes that make it the ideal energy storage compound. The feed stocks are plentiful, ammonia is easily liquefied and routinely stored in large volumes in cheap containers, and it has exceptional energy density for grid scale electrical energy storage. Ammonia can be oxidized efficiently in fuel cells or advanced Carnot cycle engines yielding water and nitrogen as end products. Because of the high energy density and low reactivity of ammonia, the capital cost for grid storage will be lower than any other storage application. This project developed the theoretical foundations of N2 catalysis on specific catalysts and provided for the first time experimental evidence for activation of Mo 2N based catalysts. Theory also revealed that the N atom adsorbed in the bridging position between two metal atoms is the critical step for catalysis. Simple electrochemical ammonia production reactors were designed and built in this project using two novel electrolyte systems. The first one demonstrated the use of ionic liquid electrolytes at room temperature and the second the use of pyrophosphate based electrolytes at intermediate temperatures (200 – 300 ºC). The mechanism of high proton conduction in the pyrophosphate materials was found to be associated with a polyphosphate second phase contrary to literature claims and ammonia production rates as high as 5X 10

  17. Energy dissipator

    NASA Technical Reports Server (NTRS)

    Delafuente, Horacio M. (Inventor); Nagy, Kornel (Inventor); Wesselski, Clarence J. (Inventor)

    1993-01-01

    An all metal energy dissipator construction is disclosed for dissipating kinetic energy force (F) by rolling balls which are forced by a tapered surface on an expandable sleeve to frictionally load a force rod. The balls are maintained in an initial position by a plate member which is biased by a spring member. A spring member returns the force rod to its initial position after a loading force is removed.

  18. Energy 101: Clean Energy Manufacturing

    SciTech Connect

    2015-07-09

    Most of us have a basic understanding of manufacturing. It's how we convert raw materials, components, and parts into finished goods that meet our essential needs and make our lives easier. But what about clean energy manufacturing? Clean energy and advanced manufacturing have the potential to rejuvenate the U.S. manufacturing industry and open pathways to increased American competitiveness. Watch this video to learn more about this exciting movement and to see some of these innovations in action.

  19. Geothermal energy

    NASA Astrophysics Data System (ADS)

    Manzella, A.

    2015-08-01

    Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG) emissions. Geothermal energy is stored in rocks and in fluids circulating in the underground. Electricity generation usually requires geothermal resources temperatures of over 100°C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology), spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Geothermal technology, which has focused so far on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth's crust.

  20. Energy Deskbook

    SciTech Connect

    Glasstone, S

    1982-06-01

    The purpose of the Energy Deskbook is to serve as a convenient reference to definitions of energy-related terms and descriptions of current and potential energy sources and their utilization. The material is presented at a low technical level with emphasis on general principles, which are not difficult to understand, rather than technology. The entries vary in length from a few lines to several pages, according to circumstances. As a general rule, each topic is defined and outlined in the first paragraph; this may be followed by a more detailed treatment, as required. An important feature of the Deskbook is the use of boldface (heavy) type for cross references. Words in the text set in boldface are the titles of articles where the particular subjects are described.

  1. Moving Energy

    SciTech Connect

    Rameau, Jon; Crabtree, George; Greene, Laura; Kwok, Wai; Johnson, Peter; Tsvelik, Alexei

    2013-07-18

    Representing the Center for Emergent Superconductivity (CES), this document is one of the entries in the Ten Hundred and One Word Challenge. As part of the challenge, the 46 Energy Frontier Research Centers were invited to represent their science in images, cartoons, photos, words and original paintings, but any descriptions or words could only use the 1000 most commonly used words in the English language, with the addition of one word important to each of the EFRCs and the mission of DOE: energy. The mission of the CES is to discover new high-temperature superconductors and improve the performance of known superconductors by understanding the fundamental physics of superconductivity.

  2. The Energy Crisis and Solar Energy

    ERIC Educational Resources Information Center

    Bockris, J. O'M.

    1974-01-01

    Examines the status of the energy crisis in Australia. Outlines energy alternatives for the 1990's and describes the present status of solar energy research and the economics of solar energy systems. (GS)

  3. Heavy ion fusion half year report, October 1, 1984-March 30, 1985

    SciTech Connect

    Not Available

    1985-06-01

    Summaries of research are given for each of the following experiments: (1) MBE-4: a four-beam induction linac experiment, (2) performance of the MBE-4 injector, (3) design procedure for acceleration and bunching in an induction linac, (4) longitudinal dynamics of MBE-4, (5) transverse beam dynamics, (6) envelope functions of high-current beam, (7) electrostatic energy analyzer, (8) longitudinal beam control, (9) a capacitive beam-charge monitor for SBTE, (10) materials R and D, (11) simulations of Robertson's lens, and (12) SBTE high sigma/sub 0/ high-current stability limits. (MOW)

  4. Creating Energy.

    ERIC Educational Resources Information Center

    Wilson, David A.

    The author of this booklet is an engineer who conducts experiments in solar energy. Here he has described basic principles of the field. He also details methods of constructing a variety of solar implements, including solar panels, solar cells, a concentrating collector and a solar furnace. The book is intended for the layman and contains…

  5. Creative Energy

    ERIC Educational Resources Information Center

    Dexter, Stephen F., Jr.

    2008-01-01

    In this article, the author shares four strategies that will keep school leaders involved in their schools, connected to their peers, and enthusiastic about it all. Here, the author describes how he has managed to balance the "impossible" with things that give him the energy to face the Mondays and start each new year. So, whether it's finding…

  6. Energy politics

    NASA Astrophysics Data System (ADS)

    McEvoy, Augustin

    2012-07-01

    In his review of Tyler Hamilton's book Mad Like Tesla (May pp44-45), Roger Bridgman writes that "in energy supply, obviously, companies cannot simply junk huge infrastructure investments in favour of something new, however good it might be". But that is exactly what Angela Merkel's administration has done in Germany with its anti-nuclear policy.

  7. Energy Materials.

    ERIC Educational Resources Information Center

    Iowa State Dept. of Public Instruction, Des Moines.

    These resource materials, developed for use by teachers in the elementary and secondary schools, are designed to provide the teacher with a bibliography, questions and answeres, and suggested classroom activities all relating to the energy problem. The materials are designed to develop a conservation ethic and greater understanding of our energy…

  8. Energy Research

    ERIC Educational Resources Information Center

    Group of Eight (NJ1), 2010

    2010-01-01

    The Group of Eight (Go8) is a coalition of leading Australian universities, intensive in research and comprehensive in general and professional education. The Go8 member universities recognise that the issue of energy usage and transformation is one of vital importance not only to Australia but to the world as a whole. The universities aim to make…

  9. Energy Theme.

    ERIC Educational Resources Information Center

    Garrahy, Dennis J.

    One of a series of social studies units designed to develop the reading and writing skills of low achievers, this student activity book focuses on the theme of energy. The unit can be used for high school classes, individual study in alternative and continuing high schools, and adult education classes. Separate sections cover early sources of…

  10. Mental Energy

    ERIC Educational Resources Information Center

    Lykken, D.T.

    2005-01-01

    Biographies of great achievers, in science as well as other disciplines, suggest that those of genius caliber possess, in addition to their intellectual gift or gifts, an extraordinary abundance of mental energy. They can focus their attention on some task for long periods without tiring or becoming distracted from the problem at hand. It is…

  11. Annual Energy Review, 2008

    SciTech Connect

    2009-06-01

    The Annual Energy Review (AER) is the Energy Information Administration's (EIA) primary report of annual historical energy statistics. For many series, data begin with the year 1949. Included are statistics on total energy production, consumption, trade, and energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, and international energy; financial and environment indicators; and data unit conversions.

  12. Energy Recovery

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The United States and other countries face the problem of waste disposal in an economical, environmentally safe manner. A widely applied solution adopted by Americans is "waste to energy," incinerating the refuse and using the steam produced by trash burning to drive an electricity producing generator. NASA's computer program PRESTO II, (Performance of Regenerative Superheated Steam Turbine Cycles), provides power engineering companies, including Blount Energy Resources Corporation of Alabama, with the ability to model such features as process steam extraction, induction and feedwater heating by external sources, peaking and high back pressure. Expansion line efficiency, exhaust loss, leakage, mechanical losses and generator losses are used to calculate the cycle heat rate. The generator output program is sufficiently precise that it can be used to verify performance quoted in turbine generator supplier's proposals.

  13. Cold energy

    SciTech Connect

    Wallace, John P.

    2015-12-04

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  14. Cold energy

    NASA Astrophysics Data System (ADS)

    Wallace, John P.

    2015-12-01

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  15. Energy management

    SciTech Connect

    Glenn, J.

    1991-10-01

    This paper is a review of the Department of Energy's (DOE) Contractor Purchasing System Review (CPSR) Program, which oversees the extensive subcontracting activities of the Department's management and operating (M and O) contractors. This review is part of a special GAO audit effort to help ensure that areas vulnerable to fraud, waste, abuse, and mismanagement are identified and that adequate corrective actions are taken. This effort focuses on 16 areas, one of which is DOE contractor oversight. This report describes the subcontracting deficiencies occurring at DOE, identifies shortcomings in DOE's CPSR Program, and discusses the corrective actions that DOE has committed to take in its CPSR Program in response to these findings.

  16. Monthly Energy Review

    EIA Publications

    2016-01-01

    The Monthly Energy Review (MER) is the U.S. Energy Information Administration's primary report of recent energy statistics. Included are total energy production, consumption, and trade; energy prices; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, and international petroleum; carbon dioxide emissions; and data unit conversions.

  17. Energy awareness luncheon and energy seminar

    SciTech Connect

    1980-07-23

    A separate abstract was prepared for each of the following: the luncheon address, energy-growth-freedom by Kenneth A. Randall; the keynote commentary, by F.S. Patton, program chairman; and four current-awareness papers on the future of oil and gas, coal, nuclear energy, and solar energy. In addition, in a section, Speaking of Energy, very brief statements by eight professional engineers on the energy challenge are included. Also, the NSPE position paper on energy policy is included.

  18. Fabrication of precision high quality facets on molecular beam epitaxy material

    DOEpatents

    Petersen, Holly E.; Goward, William D.; Dijaili, Sol P.

    2001-01-01

    Fabricating mirrored vertical surfaces on semiconductor layered material grown by molecular beam epitaxy (MBE). Low energy chemically assisted ion beam etching (CAIBE) is employed to prepare mirrored vertical surfaces on MBE-grown III-V materials under unusually low concentrations of oxygen in evacuated etching atmospheres of chlorine and xenon ion beams. UV-stabilized smooth-surfaced photoresist materials contribute to highly vertical, high quality mirrored surfaces during the etching.

  19. Energy management

    SciTech Connect

    Dingell, J.D.

    1991-10-01

    In January 1990 GAO began implementing a special audit effort to help ensure that areas vulnerable to fraud, waste, abuse, and mismanagement are identified and that appropriate corrective actions are taken. This effort focuses on 16 areas, one of which is the Department of Energy's (DOE) contracting practices. As part of this effort, the authors determined if contract audits for monitoring and overseeing DOE's contracting process were being performed and that we identify the impact or potential impact to the government when contract audits were not performed. Specifically, this paper discusses audit coverage of DOE's management and operating (M and O) contractors and DOE contracts, the problems that may occur when contract audit activity is not performed, and factors that have impeded contract audit coverage.

  20. Energy efficiency, renewable energy and sustainable development

    SciTech Connect

    Ervin, C.A.

    1994-12-31

    The Office of Energy Efficiency and Renewable Energy (EE) is part of the U.S. Department of Energy that is specifically charged with encouraging the more efficient use of energy resources, and the use of renewable energy resources - such as solar power, wind power, biomass energy and geothermal energy. In the past several years, EE has increased its emphasis on technology deployment through partnerships with states, local governments and private companies. Partnerships move new discoveries more quickly into the marketplace, where they can create jobs, prevent pollution, save resources, and produce many other benefits. The author then emphasizes the importance of this effort in a number of different sections of the paper: energy consumption pervades everything we do; U.S. energy imports are rising to record levels; transportation energy demand is increasing; U.S. energy use is increasing; population growth increases world energy demand; total costs of energy consumption aren`t always counted; world energy markets offer incredible potential; cost of renewables is decreasing; clean energy is essential to sustainable development; sustainable energy policy; sustainable energy initiatives: utilities, buildings, and transportation.

  1. Development of MBE II-VI Epilayers on GaAs(211)B

    NASA Astrophysics Data System (ADS)

    Jacobs, R. N.; Nozaki, C.; Almeida, L. A.; Jaime-Vasquez, M.; Lennon, C.; Markunas, J. K.; Benson, D.; Smith, P.; Zhao, W. F.; Smith, D. J.; Billman, C.; Arias, J.; Pellegrino, J.

    2012-10-01

    Large-area, low-cost substrates are envisioned for next-generation HgCdTe infrared focal-plane arrays (IRFPA). Si, GaAs, Ge, and InSb have been previously examined as potential candidates. Fabrication of IRFPAs based on these substrates is limited by fundamental materials properties that potentially lead to lower detector performance and operability. Lattice and thermal mismatch between the substrate and epilayer are just two of several material factors that must be considered. We have reviewed these factors in the context of more recent data, and determined it worthwhile to revisit the use of GaAs substrates for epitaxial growth of HgCdTe. Our study starts with an evaluation of the surface quality (epireadiness) of commercially available (211) B-oriented GaAs substrates. Molecular beam epitaxial growth of CdTe buffer layers and subsequent HgCdTe absorber layers are performed in separate vacuum-interconnected chambers. The importance of optimization of the CdTe buffer layer growth for high-quality HgCdTe is detailed through surface morphology and x-ray studies. x-Ray diffraction rocking-curve full-width at half-maximum values as low as 52 arcsec have been obtained. Long-wave infrared Hg1- x Cd x Te ( x = 0.23) has been grown on these buffer layers, producing cross-hatch-dominated surface morphologies, with dislocation densities as low as ˜3 × 106 cm-2. We have also obtained (for optimized layers), 80-K Hall-effect n-type carrier concentration and electron mobility of approximately ~1.5 × 1015 cm-3 and 1 × 105 cm2 V-1 s-1, respectively. Finally, we briefly compare GaAs and Si in light of our preliminary investigation.

  2. Defect reduction in MBE-grown AlN by multicycle rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Greenlee, Jordan D.; Gunning, Brendan; Feigelson, Boris N.; Anderson, Travis J.; Koehler, Andrew D.; Hobart, Karl D.; Kub, Francis J.; Doolittle, W. Alan

    2016-01-01

    Multicycle rapid thermal annealing (MRTA) is shown to reduce the defect density of molecular beam epitaxially grown AlN films. No damage to the AlN surface occurred after performing the MRTA process at 1520°C. However, the individual grain structure was altered, with the emergence of step edges. This change in grain structure and diffusion of AlN resulted in an improvement in the crystalline structure. The Raman E2 linewidth decreased, confirming an improvement in crystal quality. The optical band edge of the AlN maintained the expected value of 6.2 eV throughout MRTA annealing, and the band edge sharpened after MRTA annealing at increased temperatures, providing further evidence of crystalline improvement. X-ray diffraction shows a substantial improvement in the (002) and (102) rocking curve FWHM for both the 1400 and 1520°C MRTA annealing conditions compared to the as-grown films, indicating that the screw and edge type dislocation densities decreased. Overall, the MRTA post-growth annealing of AlN lowers defect density, and thus will be a key step to improving optoelectronic and power electronic devices. [Figure not available: see fulltext.

  3. Device Fabrication using Crystalline CdTe and CdTe Ternary Alloys Grown by MBE

    SciTech Connect

    Zaunbrecher, Katherine; Burst, James; Seyedmohammadi, Shahram; Malik, Roger; Li, Jian V.; Gessert, Timothy A.; Barnes, Teresa

    2015-06-14

    We fabricated epitaxial CdTe:In/CdTe:As homojunction and CdZnTe/CdTe and CdMgTe/CdTe heterojunction devices grown on bulk CdTe substrates in order to study the fundamental device physics of CdTe solar cells. Selection of emitter-layer alloys was based on passivation studies using double heterostructures as well as band alignment. Initial results show significant device integration challenges, including low dopant activation, high resistivity substrates and the development of low-resistance contacts. To date, the highest open-circuit voltage is 715 mV in a CdZnTe/CdTe heterojunction following anneal, while the highest fill factor of 52% was attained in an annealed CdTe homojunction. In general, all currentvoltage measurements show high series resistance, capacitancevoltages measurements show variable doping, and quantum efficiency measurements show low collection. Ongoing work includes overcoming the high resistance in these devices and addressing other possible device limitations such as non-optimum junction depth, interface recombination, and reduced bulk lifetime due to structural defects.

  4. MBE growth technology for high quality strained III-V layers

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

    1992-01-01

    III-V films are grown on large automatically perfect terraces of III-V substrates which have a different lattice constant, with temperature and Group II and V arrival rates chosen to give a Group III element stable surface. The growth is pulsed to inhibit Group III metal accumulation to low temperature, and to permit the film to relax to equilibrium. The method of the invention 1) minimizes starting step density on sample surface; 2) deposits InAs and GaAs using an interrupted growth mode (0.25 to 2 mono-layers at a time); 3) maintains the instantaneous surface stoichiometry during growth (As-stable for GaAs, In-stable for InAs); and 4) uses time-resolved RHEED to achieve aspects (1)-14 (3).

  5. Simple self-gettering differential-pump for minimizing source oxidation in oxide-MBE environment

    SciTech Connect

    Kim, Yong-Seung; Bansal, Namrata; Oh, Seongshik

    2011-07-15

    Source oxidation of easily oxidizing elements such as Ca, Sr, Ba, and Ti in an oxidizing ambient leads to their flux instability and is one of the biggest problems in the multielemental oxide molecular beam epitaxy technique. Here, the authors report a new scheme that can completely eliminate the source oxidation problem: a self-gettering differential pump using the source itself as the pumping medium. The pump simply comprises a long collimator mounted in front of the source in extended port geometry. With this arrangement, the oxygen partial pressure near the source was easily maintained well below the source oxidation regime, resulting in a stabilized flux, comparable to that of an ultrahigh-vacuum environment. Moreover, this pump has a self-feedback mechanism that allows a stronger pumping effectiveness for more easily oxidizing elements, which is a desired property for eliminating the source oxidation problem.

  6. Formation of pyramid-like nanostructures in MBE grown Si films on Si(001)

    SciTech Connect

    Galiana, Natalia; Martin, Pedro-Pablo; Garzon, L.; Rodriguez-Cañas, E.; Munuera, Carmen; Esteban-Betegon, F.; Varela del Arco, Maria; Ocal, Carmen; Alonso, Maria; Ruiz, Ana

    2010-01-01

    The growth of Si homoepitaxial layers on Si(001) substrates by molecular beam epitaxy is analyzed for a set of growth conditions in which diverse nanometric scale features develop. Using Si substrates prepared by exposure to HF vapor and annealing in ultra high vacuum, a rich variety of surface morphologies is found for different deposited layer thicknesses and substrate temperatures in a reproducible way, showing a critical dependence on both. Arrays of 3D islands (truncated pyramids), percolated ridge networks and square pit (inverted pyramids) distributions are observed. We analyze the obtained arrangements and find remarkable similarities to other semiconductor though heteroepitaxial systems. The nano-scale entities (islands or pits) display certain self assembly and ordering, concerning size, shape and spacing. Film growth sequence follows the islands-coalescence-2D growth pathway, eventually leading to optimum flat morphologies for high enough thickness and temperature.

  7. MBE grown Ga2O3 and its power device applications

    NASA Astrophysics Data System (ADS)

    Sasaki, Kohei; Higashiwaki, Masataka; Kuramata, Akito; Masui, Takekazu; Yamakoshi, Shigenobu

    2013-09-01

    N-type gallium oxide (Ga2O3) homoepitaxial thick films were grown on β-Ga2O3 (010) substrates by molecular beam epitaxy. The epitaxial growth rate was increased by more than 10 times by changing from the (100) plane to the (010) plane. The carrier concentration of the epitaxial layers could be varied within the range of 1016-1019 cm-3 by changing the Sn doping concentration. Schottky barrier diodes (SBDs) and metal-semiconductor field-effect transistors (MESFETs) on β-Ga2O3 homoepitaxial layers were demonstrated for the first time. The SBDs exhibited good device characteristics such as an ideality factor of 1.13, and high breakdown voltage about 125 V. The MESFETs also exhibited excellent characteristics such as a perfect pinch-off of the drain current, off-state breakdown voltage over 250 V, high on/off drain current ratio of around 104, and small gate leakage current. These device characteristics clearly indicate the great potential of Ga2O3 as a high-power device material.

  8. Space-charge behavior of 'Thin-MOS' diodes with MBE-grown silicon films

    NASA Technical Reports Server (NTRS)

    Lieneweg, U.; Bean, J. C.

    1984-01-01

    Basic theoretical and experimental characteristics of a novel 'Thin-MOS' technology, which has promising aspects for integrated high-frequency devices up to several hundred gigahertz are presented. The operation of such devices depends on charge injection into undoped silicon layers of about 1000-A thickness, grown by molecular beam epitaxy on heavily doped substrates, and isolation by thermally grown oxides of about 100-A thickness. Capacitance-voltage characteristics measured at high and low frequencies agree well with theoretical ones derived from uni and ambipolar space-charge models. It is concluded that after oxidation the residual doping in the epilayer is less than approximately 10 to the 16th/cu cm and rises by 3 orders of magnitude at the substrate interface within less than 100 A and that interface states at the oxide interface can be kept low.

  9. Surface defects induced by impurities in MBE-grown HgCdTe

    NASA Astrophysics Data System (ADS)

    Fu, Xiangliang; Wang, Weiqiang; Wei, Qingzhu; Wu, Jun; Chen, Lu; Wu, Yan; He, Li

    2008-03-01

    Surface defects of molecular beam epitaxially grown HgCdTe are the major concern in developing large format infrared focal plane arrays. Voids were usually observed on the HgCdTe surfaces as previously reported, they were originated either from the improper substrates preparation or from the growth condition. However, the defects formation with impurities has not been addressed. This paper presents our recent observation on defects induced by the impurities involved in the mercury beam fluxes. These defects can be craters or bumps, having a spatially clustering feature. To identify the origin of these kinds of defects, experiments were performed on HgCdTe as well as CdTe with mercury flux, and the defects were observed and analyzed by using SEM and EDAX. The result, for the first time, confirmed that impurities in the mercury beam were responsible to the formation of surface defects.

  10. MBE growth technology for high quality strained III-V layers

    NASA Technical Reports Server (NTRS)

    Grunthaner, Frank J. (Inventor); Liu, John K. (Inventor); Hancock, Bruce R. (Inventor)

    1990-01-01

    The III-V films are grown on large automatically perfect terraces of III-V substrates which have a different lattice constant, with temperature and Group III and V arrival rates chosen to give a Group III element stable surface. The growth is pulsed to inhibit Group III metal accumulation of low temperature, and to permit the film to relax to equilibrium. The method of the invention: (1) minimizes starting step density on sample surface; (2) deposits InAs and GaAs using an interrupted growth mode (0.25 to 2 monolayers at a time); (3) maintains the instantaneous surface stoichiometry during growth (As-stable for GaAs, In-stable for InAs); and (4) uses time-resolved RHEED to achieve aspects (1) through (3).

  11. Features of SOI substrates heating in MBE growth process obtained by low-coherence tandem interferometry

    NASA Astrophysics Data System (ADS)

    Volkov, P. V.; Goryunov, A.. V.; Lobanov, D. N.; Luk'yanov, A. Yu.; Novikov, A. V.; Tertyshnik, A. D.; Shaleev, M. V.; Yurasov, D. V.

    2016-08-01

    Differences in heating of silicon and silicon-on-insulator (SOI) substrates in molecular beam epitaxy were revealed by low-coherence tandem interferometry. Using this technique the interference effects which impede the correct evaluation of SOI substrate temperature by infrared pyrometers can be eliminated and so the reliable temperature readout can be achieved. It was shown that at the same thermocouple and heater power settings the real temperature of SOI substrates is higher than of silicon ones and the difference may be as high as 40-50 °C at temperatures close to 600 °C. It is supposed that such effect is caused by the additional absorption of heater radiation by the buried oxide layer in the mid-infrared range. Independent proof of this effect was obtained by growing on both types of substrates a series of structures with self-assembled Ge nanoislands whose parameters are known to be very temperature sensitive. The proposed low-coherence interferometry technique provides precise real-time control of the growth temperature and so allows formation of SiGe nanostructures with desired parameters.

  12. Investigation of the terahertz emission characteristics of MBE-grown GaAs-based nanostructures

    NASA Astrophysics Data System (ADS)

    Takatori, Satoru; Minh, Pham Hong; Estacio, Elmer; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Bailon-Somintac, Michelle; Somintac, Armando; Defensor, Michael; Gabayno, Jacqueline; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Garcia, Alipio; Ponseca, Carlito, Jr.; Salvador, Arnel; Sarukura, Nobuhiko

    2010-05-01

    We report experimental work on the terahertz emission characteristics of InAs/GaAs quantum dot (QD) structures and GaAs/AlGaAs modulation-doped heterojunctions (MDH's), excited by femtosecond laser. Results showed that the terahertz emission from MDH's can provide information on the GaAs/AlGaAs interface quality while the QD structures have the potential for being intense terahertz emitters; rivaling the emission intensity of p-type bulk InAs.

  13. MBE grown GaAsBi/GaAs multiple quantum well structures: Structural and optical characterization

    NASA Astrophysics Data System (ADS)

    Richards, Robert D.; Bastiman, Faebian; Roberts, John S.; Beanland, Richard; Walker, David; David, John P. R.

    2015-09-01

    A series of GaAsBi/GaAs multiple quantum well p-i-n diodes were grown by molecular beam epitaxy. Nomarski images showed evidence of sub-surface damage in each diode, with an increase in the cross-hatching associated with strain relaxation for the diodes containing more than 40 quantum wells. X-ray diffraction ω-2θ scans of the (004) reflections showed that multiple quantum well regions with clearly defined well periodicities were grown. The superlattice peaks of the diodes containing more than 40 wells were much broader than those of the other diodes. The photoluminescence spectra showed a redshift of 56 meV and an attenuation of nearly two orders of magnitude for the 54 and 63 well diodes. Calculations of the quantum confinement and strain induced band gap modifications suggest that the wells in all diodes are thinner than their intended widths and that both loss of quantum confinement and strain probably contributed to the observed redshift and attenuation in the 54 and 63 well diodes. Comparison of this data with that gathered for InGaAs/GaAs multiple quantum wells, suggests that the onset of relaxation occurs at a similar average strain-thickness product for both systems. Given the rapid band gap reduction of GaAsBi with Bi incorporation, this data suggests that GaAsBi is a promising photovoltaic material candidate.

  14. MBE growth and interfaces characterizations of strained HgTe/CdTe topological insulators

    NASA Astrophysics Data System (ADS)

    Thomas, C.; Baudry, X.; Barnes, J. P.; Veillerot, M.; Jouneau, P. H.; Pouget, S.; Crauste, O.; Meunier, T.; Lévy, L. P.; Ballet, P.

    2015-09-01

    Topological insulator materials like HgTe exhibit unique electronic properties at their interfaces and so peculiar attention has to be paid concerning the growth optimization. Molecular beam epitaxy of tensile-strained HgTe/CdTe is investigated as a function of the growth temperature. Crystal quality is checked by using high resolution X-rays diffraction. By combining several material characterization techniques such as scanning transmission electronic microscopy, time-of-flight secondary ion mass spectroscopy and X-rays reflectivity, we report sharp interface morphology with nanometer-scale Hg/Cd diffusion lengths.

  15. MBE Growth of AlN Nanowires on Si Substrates by Aluminizing Nucleation.

    PubMed

    E, Yanxiong; Hao, Zhibiao; Yu, Jiadong; Wu, Chao; Liu, Runze; Wang, Lai; Xiong, Bing; Wang, Jian; Han, Yanjun; Sun, Changzheng; Luo, Yi

    2015-12-01

    By introducing an aluminization process to achieve nucleation of nanowires (NWs), spontaneous growth of AlN NWs on Si substrates has been realized by plasma-assisted molecular beam epitaxy. The AlN NWs are grown from the nuclei formed by the aluminization process, and the NW density and diameter can be controlled by the aluminization parameters. The influence of growth conditions on the morphologies of AlN NWs is carefully investigated. Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms. The films are proved to be Al-polar different from the N-polar AlN NWs, which can explain the absence of newly formed NWs. Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films. PMID:26437653

  16. GaInAs-AlInAs heterostructures for optical devices grown by MBE

    NASA Technical Reports Server (NTRS)

    Welch, D. F.; Wicks, G. W.; Woodard, D. W.; Eastman, L. F.

    1983-01-01

    The band gap of Ga(0.47)In(0.53)As corresponds to an emission wavelength of about 1.65 microns. Lasers have been produced with Al(0.48)In(0.52)As as cladding layers operating at room temperature. The peak emission of Ga(0.47)In(0.53)As can be continuously varied from 1.65 to 1.2 microns by the use of the multiquantum well structures. This range of wavelengths covers the minimum loss and dispersion in optical fibers and will be applicable to integrated optics. Double heterostructure broad area lasers have been fabricated using AlInAs as cladding layers to the GaInAs active layer. Room temperature threshold current densities of 4.3 kA/sq cm have been obtained for lasers with a 4500 A active region. The first data on GaInAs/AlInAs quantum well emitters will be presented. Photoluminescence of 4 K from quantum well layers of 100, 150, and 180 A with 150 A AlInAs barrier layers produced emission at 1.27, 1.35, and 1.41 microns, respectively. Ga(0.47)In(0.52)As quantum well LEDs have also been produced which emit at 1.34 microns.

  17. Optically addressed spatial light modulators by MBE-grown nipi MQW structures

    NASA Technical Reports Server (NTRS)

    Maserjian, Joseph; Andersson, P. O.; Hancock, B. R.; Iannelli, J. M.; Eng, S. T.; Grunthaner, F. J.

    1989-01-01

    Promising approaches for achieving optically addressed spatial light modulators (O-SLMs) are investigated based on combining nipi and multiple quantum well structures. Theoretical aspects of photooptic effects achievable in such structures are treated. Test structures are grown by molecular beam epitaxy using two material systems. (In,Ga)As/GaAs and (Al,Ga)As/GaAs. Experiments show large optically controlled modulation of the absorption coefficient in the quantum well layers, a log power dependence on the control signal, millisecond and shorter time response, and generally predictable behavior. The results are encouraging for several different O-SLM device structures proposed.

  18. Passivation of MBE grown InGaSb/InAs superlattice photodiodes

    NASA Technical Reports Server (NTRS)

    Hill, Cory J.; Keo, Sam S.; Mumolo, Jason M.; Gunapala, Sarath D.

    2005-01-01

    We have performed wet chemical passivation tests on InGaSb/InAs superlattice photodiode structures grown molecular beam epitaxy. The details of the devices growth and characterization as well as the results of chemical passivation involving RuCl3 and H2SO4 with SiO2 dielectric depositions are presented.

  19. MBE Growth of AlN Nanowires on Si Substrates by Aluminizing Nucleation

    NASA Astrophysics Data System (ADS)

    E, Yanxiong; Hao, Zhibiao; Yu, Jiadong; Wu, Chao; Liu, Runze; Wang, Lai; Xiong, Bing; Wang, Jian; Han, Yanjun; Sun, Changzheng; Luo, Yi

    2015-10-01

    By introducing an aluminization process to achieve nucleation of nanowires (NWs), spontaneous growth of AlN NWs on Si substrates has been realized by plasma-assisted molecular beam epitaxy. The AlN NWs are grown from the nuclei formed by the aluminization process, and the NW density and diameter can be controlled by the aluminization parameters. The influence of growth conditions on the morphologies of AlN NWs is carefully investigated. Island-like films are found to grow between the NWs due to poor migration ability of Al adatoms. The films are proved to be Al-polar different from the N-polar AlN NWs, which can explain the absence of newly formed NWs. Increasing the V/III ratio can efficiently suppress the growth of Al-polar AlN films.

  20. MBE growth of mid-IR type-II interband laser diodes

    NASA Astrophysics Data System (ADS)

    Schmitz, J.; Mermelstein, C.; Kiefer, R.; Walther, M.; Wagner, J.

    2005-05-01

    We report on molecular beam epitaxial growth and characterization of InAs/GaInSb/InAs/AlGaAsSb type-II miniband-to-bound state W-lasers. Laser core structures were characterized using photoluminescence, high resolution X-ray diffraction and Raman spectroscopy to reveal the best growth conditions. The growth temperature for the laser core was varied in the range between 380 °C and 460 °C and found to be optimal at 420 °C. Optimized laser active regions were embedded between 600 nm AlGaAsSb separate confinement layers which in turn were sandwiched between 1.5 μm thick n- and p-doped Al 0.85Ga 0.15As 0.07Sb 0.93 cladding layers. The upper cladding was capped with a 100 nm p +-GaSb contact layer. The growth temperature of the upper separate confinement and cladding layer was varied between 470 °C and 530 °C to reveal the influence on laser performance. Laser emission is observed near 3.2 μm. Devices with uncoated facets, mounted substrate side down could be operated up to a temperature of 185 K in continuous-wave (cw) mode. Single ended output powers of 144 mW in cw mode and 330 mW in pulsed operation were obtained for a 5-period diode laser structure with HR/AR coated mirror facets at an operation temperature of 110 K.

  1. Save Energy Now

    SciTech Connect

    Not Available

    2006-01-01

    This DOE Industrial Technologies Program brochure informs industrial audiences about Save Energy Now, part of ''Easy Ways to Save Energy'', a national campaign to save energy and ensure energy security.

  2. Cutting Energy Costs.

    ERIC Educational Resources Information Center

    Rittner-Heir, Robbin M.

    2003-01-01

    Describes school-district energy-conservation efforts including teaching students to save energy, retrofitting schools, hiring energy consulting companies, and activating the sleep function on computer monitors. Also describes the federal Energy Star program (www.energystar.gov). (PKP)

  3. Energy and Resources

    ERIC Educational Resources Information Center

    Sorensen, Bent

    1975-01-01

    Discusses the feasibility of utilizing continuous sources of of energy, particularly solar and wind energy. Outlines an energy plan for Denmark, which would supply all of Denmark's energy needs by the year 2050. (MLH)

  4. Wind energy systems

    NASA Technical Reports Server (NTRS)

    Stewart, H. J.

    1978-01-01

    A discussion on wind energy systems involved with the DOE wind energy program is presented. Some of the problems associated with wind energy systems are discussed. The cost, efficiency, and structural design of wind energy systems are analyzed.

  5. Seasonal thermal energy storage

    SciTech Connect

    Allen, R.D.; Kannberg, L.D.; Raymond, J.R.

    1984-05-01

    This report describes the following: (1) the US Department of Energy Seasonal Thermal Energy Storage Program, (2) aquifer thermal energy storage technology, (3) alternative STES technology, (4) foreign studies in seasonal thermal energy storage, and (5) economic assessment.

  6. Annual energy review 1996

    SciTech Connect

    1997-07-01

    This report presents historical energy statistics on all major energy activities. The statistics cover consumption, production, trade, stock, and prices, for all major energy commodities including fossil fuels, electricity, and renewable energy sources.

  7. Integrated rural energy planning

    SciTech Connect

    El Mahgary, Y.; Biswas, A.K.

    1985-01-01

    This book presents papers on integrated community energy systems in developing countries. Topics considered include an integrated rural energy system in Sri Lanka, rural energy systems in Indonesia, integrated rural food-energy systems and technology diffusion in India, bringing energy to the rural sector in the Philippines, the development of a new energy village in China, the Niaga Wolof experimental rural energy center, designing a model rural energy system for Nigeria, the Basaisa village integrated field project, a rural energy project in Tanzania, rural energy development in Columbia, and guidelines for the planning, development and operation of integrated rural energy projects.

  8. Energy 101: Energy Efficient Commercial Buildings

    ScienceCinema

    None

    2014-06-26

    Learn how commercial buildings can incorporate whole-building design to save energy and money while enhancing performance and comfort. This video highlights several energy-saving features of the Research Support Facility at the Energy Department's National Renewable Energy Laboratory-a model for high-performance office building design.

  9. Collecting Solar Energy. Solar Energy Education Project.

    ERIC Educational Resources Information Center

    O'Brien, Alexander

    This solar energy learning module for use with junior high school students offers a list of activities, a pre-post test, job titles, basic solar energy vocabulary, and diagrams of solar energy collectors and installations. The purpose is to familiarize students with applications of solar energy and titles of jobs where this knowledge could be…

  10. Energy. Nebraska Home Economics Energy Management Guide.

    ERIC Educational Resources Information Center

    Nickisch, Marge Hill

    The Nebraska Home Economics Energy Management Guide is composed of 25 individual lessons in 5 units plus a resource section. The introductory unit discusses basic principles in decision-making, the historical development of energy sources and use, and the rationale for energy management. The next four units focus on energy management in housing,…

  11. A Nonlinear Energy Sink with Energy Harvester

    NASA Astrophysics Data System (ADS)

    Kremer, Daniel

    The transfer of energy between systems is a natural process, manifesting in many different ways. In engineering transferable energy can be considered wanted or unwanted. Specifically in mechanical systems, energy transfer can occur as unwanted vibrations, passing from a source to a receiver. In electrical systems, energy transfer can be desirable, where energy from a source may be used elsewhere. This work proposes a method to combine the two, converting unwanted mechanical energy into useable electrical energy. A nonlinear energy sink (NES) is a vibration absorber that passively localizes vibrational energy, removing mechanical energy from a primary system. Consisting of a mass-spring-damper such that the stiffness is essentially nonlinear, a NES can localize vibrational energy from a source and dissipate it through damping. Replacing the NES mass with a series of magnets surrounded by coils fixed to the primary mass, the dissipated energy can be directly converted to electrical energy. A NES with energy harvesting properties is constructed and introduced. The system parameters are identified, with the NES having an essentially cubic nonlinear stiffness. A transduction factor is quantified linking the electrical and mechanical systems. An analytic analysis is carried out studying the transient and harmonically excited response of the system. It is found that the energy harvesting does not reduce the vibrational absorption capabilities of the NES. The performance of the system in both transient and harmonically excited responses is found to be heavily influenced by input energies. The system is tested, with good match to analytic results.

  12. Energy 101: Energy Efficient Commercial Buildings

    SciTech Connect

    2014-03-14

    Learn how commercial buildings can incorporate whole-building design to save energy and money while enhancing performance and comfort. This video highlights several energy-saving features of the Research Support Facility at the Energy Department's National Renewable Energy Laboratory-a model for high-performance office building design.

  13. Energy Informatics Panel (Presentation)

    SciTech Connect

    Brodt-Giles, D.

    2012-06-01

    Designed to be the world's most comprehensive, open, and collaborative energy information network, Open Energy Information (OpenEI - openei.org) supplies essential energy data to decision makers and supports a global energy transformation. The platform, sponsored by the U.S. Department of Energy (DOE) and developed by the National Renewable Energy Laboratory (NREL), is intended for global contribution and collaboration.

  14. Energy: The Surprising Decade.

    ERIC Educational Resources Information Center

    Fowler, John M.

    1983-01-01

    Stresses the importance of energy education and discusses various aspects of and trends related to energy in the United States. These include energy costs, recession and energy conservation, the nuclear debate, environmental concerns (including acid rain), solar energy, technological developments, energy policy/politics, and projection of energy…

  15. ENERGY REQUIREMENTS OF INFANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To estimate the energy requirements of infants from total energy expenditure and energy deposition during growth. Design: Energy requirements during infancy were estimated from total energy expenditure measured by the doubly labeled water method and energy deposition based on measured pr...

  16. Energy technology glossary

    SciTech Connect

    Bishop, C.T.

    1986-06-23

    This glossary covers six topics: Energy Concepts; Nuclear Energy; Fossil Fuels; Solar Energy; Earth Energies; and Energy Technologies in one alphabetical listing of all energy related terms. Two tables at the end of the glossary define the relationships between the more commonly used units are given.

  17. The ABC's of Energy.

    ERIC Educational Resources Information Center

    Barrow, Lloyd H., Ed.; Bitner, Betty L., Ed.

    This resource guide consists of activities related to 26 separate energy topics (one for each letter of the alphabet). Topic areas are: approaches to problems related to energy shortages; biomass; conserving energy; demand for energy in the year 2000; economics and energy; fossil fuels; geothermal energy; hydroelectric power; insulation; energy…

  18. Tribal Energy Program, Assisting Tribes to Realize Their Energy Visions (Brochure), Energy Efficiency & Renewable Energy (EERE)

    SciTech Connect

    Not Available

    2013-06-01

    This 12-page brochure provides an overview of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy's Tribal Energy Program and describes the financial, technical, and educational assistance it provides to help tribes develop their renewable energy resources and reduce their energy consumption.

  19. Arctic Energy Resources: Energy Research

    NASA Astrophysics Data System (ADS)

    Gryc, George

    1984-04-01

    Arctic Energy Resources is a volume of 26 papers recording the proceedings of the Comite' Arctique International Conference, held at the Veritas Centre, Oslo, Norway, September 22-24, 1982. This was the fourth of a series of meetings on the Arctic organized by the Comite', an organization established in the Principality of Monaco with the active support of H.S.H. Prince Rainer III. The fourth Conference was opened by H.R.H. Crown Prins Harald of Norway, a noble beginning for a noble objective.The North Polar Region has drawn world attention recently because of several large hydrocarbon and other mineral discoveries and because of major political and environmental actions in the North American Arctic. Since 1923 when Naval Petroleum Reserve number 4 (NPR-4) was established, northern Alaska has been considered a major petroleum province. It was first explored systematically with modern techniques from 1943 to 1953. In 1958, Alaska became a state, and both federal and state lands in northern Alaska were available for private exploration. Building on the knowledge base provided by the Pet-4 program and its spinoff research laboratory at Barrow, industry explored the area east of NPR-4 and discovered the largest hydrocarbon accumulation (9.6 bbl crude oil and 26 Tcf (trillion cubic feet) gas) in North America at Prudhoe Bay. Concerns for environmental impacts, including oil spills, led to the passing of the National Environmental Policy Act in 1969. In 1970, over 9 million acres were set aside, now known as the Arctic National Wildlife Range, and in 1971 the Alaska Native Claims Settlement Act was passed by the U.S. Congress. The Arab oil embargo of 1973 heightened the energy crisis and changed the economic basis for further exploration in the Arctic. The convergence of these events dramatically changed the balance of power and the pace of activity in the North American Arctic.

  20. GaSb thermophotovoltaics: current challenges and solutions

    NASA Astrophysics Data System (ADS)

    Rahimi, N.; Herrera, D. J.; Aragon, A.; Shima, D. M.; Romero, O. S.; Rotter, T. J.; Busani, T.; Lavrova, O.; Balakrishnan, G.; Lester, L. F.

    2015-03-01

    GaSb thermophotovoltaic cells fabricated using Molecular Beam Epitaxy (MBE) and ion implantation techniques are studied. Challenges including different defect formation mechanisms using MBE and ion-induced defects using ion implantation were investigated by cross-sectional Transmission Electron Microscopy (XTEM), X-Ray Diffraction spectroscopy (XRD) and Scanning Electron Microscopy (SEM). For MBE grown TPVs, several approaches were used to suppress defects, including substrate preparation and using different MBE reactors. For ion-implanted TPVs, different implant doses and energies were tested to minimize the crystal damage and various Rapid Thermal Anneal (RTA) process recipes were studied to maximize the crystal recovery. Large area TPV cells with 1 × 1 cm dimensions were fabricated using these techniques, then electrically and optically characterized. Ideality factors and dark saturation currents were measured and compared for various TPVs.

  1. Fusion energy

    NASA Astrophysics Data System (ADS)

    1990-09-01

    The main purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor through the united efforts of many technologically advanced countries. The ITER terms of reference, issued jointly by the European Community, Japan, the USSR, and the United States, call for an integrated international design activity and constitute the basis of current activities. Joint work on ITER is carried out under the auspices of the International Atomic Energy Agency (IAEA), according to the terms of quadripartite agreement reached between the European Community, Japan, the USSR, and the United States. The site for joint technical work sessions is at the Max Planck Institute of Plasma Physics. Garching, Federal Republic of Germany. The ITER activities have two phases: a definition phase performed in 1988 and the present design phase (1989 to 1990). During the definition phase, a set of ITER technical characteristics and supporting research and development (R and D) activities were developed and reported. The present conceptual design phase of ITER lasts until the end of 1990. The objectives of this phase are to develop the design of ITER, perform a safety and environmental analysis, develop site requirements, define future R and D needs, and estimate cost, manpower, and schedule for construction and operation. A final report will be submitted at the end of 1990. This paper summarizes progress in the ITER program during the 1989 design phase.

  2. Fusion energy

    SciTech Connect

    Not Available

    1990-09-01

    The main purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor through the united efforts of many technologically advanced countries. The ITER terms of reference, issued jointly by the European Community, Japan, the USSR, and the United States, call for an integrated international design activity and constitute the basis of current activities. Joint work on ITER is carried out under the auspices of the International Atomic Energy Agency (IAEA), according to the terms of quadripartite agreement reached between the European Community, Japan, the USSR, and the United States. The site for joint technical work sessions is at the MaxPlanck Institute of Plasma Physics. Garching, Federal Republic of Germany. The ITER activities have two phases: a definition phase performed in 1988 and the present design phase (1989--1990). During the definition phase, a set of ITER technical characteristics and supporting research and development (R D) activities were developed and reported. The present conceptual design phase of ITER lasts until the end of 1990. The objectives of this phase are to develop the design of ITER, perform a safety and environmental analysis, develop site requirements, define future R D needs, and estimate cost, manpower, and schedule for construction and operation. A final report will be submitted at the end of 1990. This paper summarizes progress in the ITER program during the 1989 design phase.

  3. Photovoltaic energy

    NASA Astrophysics Data System (ADS)

    1990-01-01

    In 1989, the U.S. photovoltaic industry enjoyed a growth rate of 30 percent in sales for the second year in a row. This sends a message that the way we think about electricity is changing. Instead of big energy projects that perpetuate environmental and economic damage, there is a growing trend toward small renewable technologies that are well matched to end-user needs and operating conditions. As demand grows and markets expand, investment capital will be drawn to the industry and new growth trends will emerge. The photovoltaic industry around the world achieved record shipments also. Worldwide shipments of photovoltaic (PV) modules for 1989 totaled more than 40 megawatts (MW), nearly a 20 percent increase over last year's shipments. The previous two years showed increases in worldwide shipments of 23 and 25 percent, respectively. If this growth rate continues through the 1990s, as industry back orders would indicate, 300 to 1000 MW of PV-supplied power could be on line by 2000. Photovoltaic systems have low environmental impact and they are inexpensive to operate and maintain. Using solid-state technology, PV systems directly convert sunlight to electricity without high-temperature fluids or moving parts that could cause mechanical failure. This makes the technology very reliable.

  4. Renewable Energy: Energy Security and Sustainability

    NASA Astrophysics Data System (ADS)

    Turner, John

    2002-03-01

    Renewable energy offers the possibility of providing a complete, sustainable energy infrastructure without anthropogenic emission of CO2. Large-scale implementation of renewable technologies would eliminate the need to develop and implement sequestration systems, by reducing the use of, and ultimately eliminating fossil based energy production. Renewable energy also offers energy security because indigenous resources are sufficient. The major renewable energy systems include phovoltaics (solar cells), solar thermal (electric and thermal), wind, biomass (plants and trees), hydroelectric, ocean, and geothermal. Given the intermittent nature of solar energy, only those energy systems that are coupled to an energy storage technology will be viable. Among the energy storage technologies are hydrogen, batteries, flywheels, superconductivity, ultracapacitors, pumped hydro, molten salts (for thermal storage), and compressed gas. One of the most versatile energy storage systems and the best energy carrier for transportation is hydrogen. This talk will review some of the basic renewable energy systems, present possible pathways for the implementation of hydrogen into the energy infrastructure and offer research areas that need to be addressed to increase the viability of these renewable energy technologies.

  5. Monthly Energy Review, July 1992

    SciTech Connect

    1992-07-27

    The Monthly Energy Review is prepared by the Energy Information Administration. Topics discussed include: Energy Overview, Energy Consumption, Petroleum, Natural Gas, Oil and Gas Resource Development, Coal, Electricity, Nuclear Energy, Energy Prices, International Energy. (VC)

  6. 75 FR 30014 - Office of Energy Efficiency and Renewable Energy; Energy Efficiency and Conservation Block Grant...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-28

    ... of Energy Efficiency and Renewable Energy; Energy Efficiency and Conservation Block Grant Program AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Notice. SUMMARY... Efficiency and Renewable Energy (EERE), has experienced historic growth and unprecedented workload...

  7. Global view of energy

    SciTech Connect

    Kursunoglu, B.N.; Millunzi, A.C.; Perlmutter, A.

    1982-01-01

    This book contains selected papers presented at the fourth interdisciplinary international forum on the Geopolitics of Energy. Topics included: energy demand; energy modeling; urgency of world energy problems; nuclear fission; progress in nuclear fusion; financing energy investments; conservation of energy in developed countries; public safety - risks and benefits; and atmospheric carbon dioxide. A separate abstract was prepared for each of the 25 papers for inclusion in the Energy Data Base; all will appear in Energy Abstracts for Policy Analysis and five in Energy Research Abstracts (ERA). (RJC)

  8. Guam Strategic Energy Plan

    SciTech Connect

    Conrad, M. D.

    2013-07-01

    Describes various energy strategies available to Guam to meet the territory's goal of diversifying fuel sources and reducing fossil energy consumption 20% by 2020.The information presented in this strategic energy plan will be used by the Guam Energy Task Force to develop an energy action plan. Available energy strategies include policy changes, education and outreach, reducing energy consumption at federal facilities, and expanding the use of a range of energy technologies, including buildings energy efficiency and conservation, renewable electricity production, and alternative transportation. The strategies are categorized based on the time required to implement them.

  9. Direct Conversion of Energy.

    ERIC Educational Resources Information Center

    Corliss, William R.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Direct energy conversion involves energy transformation without moving parts. The concepts of direct and dynamic energy conversion plus the laws governing energy conversion are investigated. Among the topics…

  10. Insight: An Energy Curriculum.

    ERIC Educational Resources Information Center

    Kohl, Herb

    1979-01-01

    The author explains some of the activities he uses in his upper elementary energy curriculum when dealing with these topics: the definition of energy; gasoline consumption; energy conversion; solar energy; and the politics of energy. Resource agencies to which students may write for information are listed. (SJL)

  11. Energy Conservation Simplified

    ERIC Educational Resources Information Center

    Hecht, Eugene

    2008-01-01

    The standard formulation of energy conservation involves the subsidiary ideas of kinetic energy ("KE"), work ("W"), thermal energy, internal energy, and a half-dozen different kinds of potential energy ("PE"): elastic, chemical, nuclear, gravitational, and so forth. These quantities came to be recognized during the centuries over which the…

  12. The Science of Energy.

    ERIC Educational Resources Information Center

    National Energy Education Development Project, Reston, VA.

    This unit of study for secondary students focuses on energy uses, energy sources, energy forms, and energy conversion. The unit is designed to take five 45-minute class sessions. In the first class session, the teacher conducts several energy conversion experiments. In subsequent sessions, students are divided into seven groups and each is…

  13. Monthly Energy Review

    SciTech Connect

    1996-05-28

    This publication presents an overview of the Energy information Administration`s recent monthly energy statistics. The statistics cover the major activities of US production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors. Two brief ``energy plugs`` (reviews of EIA publications) are included, as well.

  14. The Energy Book.

    ERIC Educational Resources Information Center

    Krockover, Gerald

    1978-01-01

    Presents an eight-page teaching guide on energy education for use in elementary school classrooms. Included are information on what energy is and where it comes from, ideas on how to mount a schoolwide energy awareness campaign, activities for teaching energy conservation, ideas on how to organize an energy fair, and a resource bibliography. (JMB)

  15. Winning the Energy Game.

    ERIC Educational Resources Information Center

    Zielinski, Edward J.; Bethel, Lowell J.

    1983-01-01

    Describes the use of an Energy-Environment Simulator in environmental/energy education programs. The simulator is a specially designed analog computer that simulates real-world conditions of energy production and use. Energy resources, demands, and the environmental effects of energy use are programmed into the computer. (Author/JN)

  16. Solar energy collector

    DOEpatents

    Brin, Raymond L.; Pace, Thomas L.

    1978-01-01

    The invention relates to a solar energy collector comprising solar energy absorbing material within chamber having a transparent wall, solar energy being transmitted through the transparent wall, and efficiently absorbed by the absorbing material, for transfer to a heat transfer fluid. The solar energy absorbing material, of generally foraminous nature, absorbs and transmits the solar energy with improved efficiency.

  17. Fission Energy and Other Sources of Energy

    ERIC Educational Resources Information Center

    Alfven, Hannes

    1974-01-01

    Discusses different forms of energy sources and basic reasons for the opposition to the use of atomic energy. Suggests that research efforts should also be aimed toward the fission technology to make it acceptable besides major research studies conducted in the development of alternative energy sources. (CC)

  18. Science Activities in Energy: Chemical Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 15 activities relating to chemical energy. Activities are simple, concrete experiments for fourth, fifth and sixth grades which illustrate principles and problems relating to energy. Each activity is outlined on a single card which is introduced by a question. A teacher's…

  19. Science Activities in Energy: Electrical Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 16 activities relating to electrical energy. Activities are simple, concrete experiments for fourth, fifth and sixth grades which illustrate principles and problems relating to energy. Each activity is outlined in a single card which is introduced by a question. A teacher's…

  20. Science Activities in Energy: Solar Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 12 activities relating to solar energy. Activities are simple, concrete experiments for fourth, fifth, and sixth grades, which illustrate principles and problems relating to energy. Each activity is outlined on a single card which is introduced by a question. A teacher's supplement…

  1. Energy Production Systems. Energy Technology Series.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This course in energy production systems is one of 15 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in…

  2. Representing Energy. II. Energy Tracking Representations

    ERIC Educational Resources Information Center

    Scherr, Rachel E.; Close, Hunter G.; Close, Eleanor W.; Vokos, Stamatis

    2012-01-01

    The Energy Project at Seattle Pacific University has developed representations that embody the substance metaphor and support learners in conserving and tracking energy as it flows from object to object and changes form. Such representations enable detailed modeling of energy dynamics in complex physical processes. We assess student learning by…

  3. Energy for Mankind

    ERIC Educational Resources Information Center

    Pincherle, L.; Rice-Evans, P.

    1977-01-01

    Discusses statistics concerning world energy requirements and supplies of different types of fuels. Also discusses the storage and transmission of energy and pollution problems related to energy utilization. (MLH)

  4. The Energy Crisis

    ERIC Educational Resources Information Center

    Sandercock, Ted

    1973-01-01

    Discusses the nature of energy, the ways in which it is used in our society, non-polluting sources of energy, and means by which energy can be conserved to alleviate the shortage and minimize environmental degradation. (JR)

  5. Alcohol Energy Drinks

    MedlinePlus

    ... Home / About Addiction / Alcohol / Alcohol Energy Drinks Alcohol Energy Drinks Read 14635 times font size decrease font size increase font size Print Email Alcohol energy drinks (AEDs) or Caffeinated alcoholic beverages (CABs) are ...

  6. Energy Use in Manufacturing

    EIA Publications

    2006-01-01

    This report addresses both manufacturing energy consumption and characteristics of the manufacturing economy related to energy consumption. In addition, special sections on fuel switching capacity and energy-management activities between 1998 and 2002 are also featured in this report.

  7. Alcohol Energy Drinks

    MedlinePlus

    ... Home / About Addiction / Alcohol / Alcohol Energy Drinks Alcohol Energy Drinks Read 17728 times font size decrease font size increase font size Print Email Alcohol energy drinks (AEDs) or Caffeinated alcoholic beverages (CABs) are ...

  8. Save Energy Now Resources

    SciTech Connect

    2008-03-01

    The U.S. Department of Energy (DOE) provides information resources to industrial energy users and partnering organizations to help the nation’s industrial sector save energy and improve productivity.

  9. Some Myths Surrounding Energy.

    ERIC Educational Resources Information Center

    Beynon, John

    1990-01-01

    Energy as an abstract concept is discussed, and the effect of using inappropriate language in the teaching of energy is considered. The storage of energy is illustrated using gravitation and the combustion of coal as examples. (CW)

  10. One Energy Miser's Plan.

    ERIC Educational Resources Information Center

    American School and University, 1981

    1981-01-01

    A Kansas school district uses computers, an energy management consultant, retrofitting, and school cleaning scheduling to reduce energy use. Documented results of energy use were part of successful applications by nine school administrators for retrofitting grants. (MLF)

  11. Oneida Tribe Energy Audits

    SciTech Connect

    Olson, Ray; Schubert, Eugene

    2014-08-15

    Project funding energy audits of 44 Tribally owned buildings operated by the Oneida Tribe of Indians of WI. Buildings were selected for their size, age, or known energy concerns and total over 1 million square feet. Audits include feasibility studies, lists of energy improvement opportunities, and a strategic energy plan to address cost effective ways to save energy via energy efficiency upgrades over the short and long term.

  12. Nation's energy dilemma

    SciTech Connect

    Krenz, J.H.

    1981-05-01

    Because we understand production patterns better than energy-use patterns, Americans find it difficult to grasp the significance of resource scarcity and depletion and the need to continue energy inputs to sustain a developed society. Arguments against more-efficient energy use cite cost and life-style disruptions, but these must be weighed against the socio-economic impacts of traditional energy expansion. A new energy consciousness should be applied to investment decisions involving energy to eliminate waste. This will require changes in products, habits, and attitudes. Policies that will develop data and expertise in the thermodynamic principles of energy usage will help to change the way energy is valued. (DCK)

  13. Energy Choices for Consumers

    ERIC Educational Resources Information Center

    Nolan, William T.

    1977-01-01

    Sample problems concerning energy consumption and conservation with air conditioners, electric ranges, refrigerators and televisions are provided. The energy efficiency ratio (EER) is also discussed. (CP)

  14. Three Forms of Energy.

    ERIC Educational Resources Information Center

    Petursson, Sigthor

    2003-01-01

    Identifies practical ways to introduce students to thermodynamic concepts, such as heat and mechanical energy. Introduces three different energy transformations that everyone should be able to envisage. (SOE)

  15. Western Energy Corridor -- Energy Resource Report

    SciTech Connect

    Leslie Roberts; Michael Hagood

    2011-06-01

    The world is facing significant growth in energy demand over the next several decades. Strategic in meeting this demand are the world-class energy resources concentrated along the Rocky Mountains and northern plains in Canada and the U.S., informally referred to as the Western Energy Corridor (WEC). The fossil energy resources in this region are rivaled only in a very few places in the world, and the proven uranium reserves are among the world's largest. Also concentrated in this region are renewable resources contributing to wind power, hydro power, bioenergy, geothermal energy, and solar energy. Substantial existing and planned energy infrastructure, including refineries, pipelines, electrical transmission lines, and rail lines provide access to these resources.

  16. Energy planning and energy efficiency assistance

    SciTech Connect

    Markel, L.

    1995-12-31

    Electrotek is an engineering services company specializing in energy-related programs. Clients are most utilities, large energy users, and the U.S. Electric Power Research Institute. Electrotek has directed energy projects for the U.S. Agency for International Development and the U.S. Department of Energy in Poland and other countries of Central Europe. The objective is to assist the host country organizations to identify and implement appropriate energy efficiency and pollution reduction technologies, to transfer technical and organizational knowledge, so that further implementations are market-driven, without needed continuing foreign investment. Electrotek has worked with the Silesian Power Distribution Company to design an energy efficiency program for industrial customers that has proven to be profitable for the company and for its customers. The program has both saved energy and costs, and reduced pollution. The program is expanding to include additional customers, without needing more funding from the U.S. government.

  17. Monthly energy review, July 1993

    SciTech Connect

    Not Available

    1993-07-27

    This publication presents information and compiled data on energy sources. The following information is presented: energy overview; energy consumption; petroleum; natural gas; oil and gas resource development; coal; electricity; nuclear energy; energy prices; and international energy.

  18. Energy transition in developing countries

    SciTech Connect

    Not Available

    1984-01-01

    Contents cover: The energy outlook; Energy demand management; Energy supply prospects and issues; Management of the energy sector; Financing energy investments; The role of the World Bank; Assumptions used for natural gas netback studies; and World energy indicators.

  19. Geothermal Energy Program overview

    SciTech Connect

    Not Available

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained with the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost- effective heat and electricity for our nation's energy needs. Geothermal energy -- the heat of the Earth -- is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40% of the total US energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The US Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma ( the four types of geothermal energy) still depends on the technical advancements sought by DOE's Geothermal Energy Program.

  20. Geothermal energy program overview

    NASA Astrophysics Data System (ADS)

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained within the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost-effective heat and electricity for our nation's energy needs. Geothermal energy - the heat of the Earth - is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40 percent of the total U.S. energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The U.S. Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma (the four types of geothermal energy), still depends on the technical advancements sought by DOE's Geothermal Energy Program.

  1. Monthly energy review June 1996

    SciTech Connect

    1996-06-01

    This report presents data on energy consumption, fossil fuels imports, supply and disposition, energy prices, electricity, nuclear energy electricity production, and international energy production and consumption.

  2. Alternative Energy Development and China's Energy Future

    SciTech Connect

    Zheng, Nina; Fridley, David

    2011-06-15

    In addition to promoting energy efficiency, China has actively pursued alternative energy development as a strategy to reduce its energy demand and carbon emissions. One area of particular focus has been to raise the share of alternative energy in China’s rapidly growing electricity generation with a 2020 target of 15% share of total primary energy. Over the last ten years, China has established several major renewable energy regulations along with programs and subsidies to encourage the growth of non-fossil alternative energy including solar, wind, nuclear, hydro, geothermal and biomass power as well as biofuels and coal alternatives. This study thus seeks to examine China’s alternative energy in terms of what has and will continue to drive alternative energy development in China as well as analyze in depth the growth potential and challenges facing each specific technology. This study found that despite recent policies enabling extraordinary capacity and investment growth, alternative energy technologies face constraints and barriers to growth. For relatively new technologies that have not achieved commercialization such as concentrated solar thermal, geothermal and biomass power, China faces technological limitations to expanding the scale of installed capacity. While some alternative technologies such as hydropower and coal alternatives have been slowed by uneven and often changing market and policy support, others such as wind and solar PV have encountered physical and institutional barriers to grid integration. Lastly, all alternative energy technologies face constraints in human resources and raw material resources including land and water, with some facing supply limitations in critical elements such as uranium for nuclear, neodymium for wind and rare earth metals for advanced solar PV. In light of China’s potential for and barriers to growth, the resource and energy requirement for alternative energy technologies were modeled and scenario analysis

  3. Campus Energy Modeling Platform

    Energy Science and Technology Software Center (ESTSC)

    2014-09-19

    NREL's Campus Energy Modeling project provides a suite of simulation tools for integrated, data driven energy modeling of commercial buildings and campuses using Simulink. The tools enable development of fully interconnected models for commercial campus energy infrastructure, including electrical distribution systems, district heating and cooling, onsite generation (both conventional and renewable), building loads, energy storage, and control systems.

  4. Saving Energy Dollars.

    ERIC Educational Resources Information Center

    Cray, Douglas W.

    1993-01-01

    The Comprehensive National Energy Policy Act of 1992 encourages energy-conservation measures and proposes matching federal energy-conservation funds with state programs to achieve energy conservation in public buildings. Presents a sampler of conservation projects in Massachusetts, Connecticut, Florida, and Minnesota. (MLF)

  5. Home Energy Score

    SciTech Connect

    2011-12-16

    The Home Energy Score allows a homeowner to compare her or his home's energy consumption to that of other homes, similar to a vehicle's mile-per-gallon rating. A home energy assessor will collect energy information during a brief home walk-through and then score that home on a scale of 1 to 10.

  6. Energy Balance and Obesity

    PubMed Central

    Hill, James O.; Wyatt, Holly R.; Peters, John C.

    2012-01-01

    This paper describes the interplay among energy intake, energy expenditure and body energy stores and illustrates how an understanding of energy balance can help develop strategies to reduce obesity. First, reducing obesity will require modifying both energy intake and energy expenditure and not simply focusing on either alone. Food restriction alone will not be effective in reducing obesity if human physiology is biased toward achieving energy balance at a high energy flux (i.e. at a high level of energy intake and expenditure). In previous environments a high energy flux was achieved with a high level of physical activity but in today's sedentary environment it is increasingly achieved through weight gain. Matching energy intake to a high level of energy expenditure will likely be more a more feasible strategy for most people to maintain a healthy weight than restricting food intake to meet a low level of energy expenditure. Second, from an energy balance point of view we are likely to be more successful in preventing excessive weight gain than in treating obesity. This is because the energy balance system shows much stronger opposition to weight loss than to weight gain. While large behavior changes are needed to produce and maintain reductions in body weight, small behavior changes may be sufficient to prevent excessive weight gain. In conclusion, the concept of energy balance combined with an understanding of how the body achieves balance may be a useful framework in helping develop strategies to reduce obesity rates. PMID:22753534

  7. Alternatives in solar energy

    NASA Technical Reports Server (NTRS)

    Schueler, D. G.

    1978-01-01

    Although solar energy has the potential of providing a significant source of clean and renewable energy for a variety of applications, it is expected to penetrate the nation's energy economy very slowly. The alternative solar energy technologies which employ direct collection and conversion of solar radiation as briefly described.

  8. Energy and Education Handbook.

    ERIC Educational Resources Information Center

    Campbell, Bruce, Comp.

    Background papers are supplied that outline the energy education needs for New Jersey schools and show the dimensions of the energy crisis in terms of the availability of fuel sources. A curriculum model for Introduction to Energy and Energy Conservation is supplied with background information written for all teachers from kindergarten through…

  9. Energy Efficiency in Libraries.

    ERIC Educational Resources Information Center

    Lewis, Eleanor J.; And Others

    1993-01-01

    Shows how libraries can save money and energy with energy-efficient technologies, improving maintenance, and encouraging staff efforts to conserve energy. Specific techniques such as life-cycle cost analysis and energy audits focusing on lighting, heating, ventilation, air conditioning, and water efficiency are described. Funding options and…

  10. The Energy To Teach.

    ERIC Educational Resources Information Center

    Graves, Donald H.

    2002-01-01

    Learns from teachers themselves what gave and took away energy from their teaching experiences. Considers what gives teachers energy or takes it away and what is a waste of time. Outlines and discusses eight energy principles. Concludes that most individuals are energy-filled when they are learning themselves. (SG)

  11. Monthly energy review

    SciTech Connect

    1997-12-01

    This document presents an overview of the Energy Information Administration`s (EIA) recent monthly energy statistics. The statistics cover the major activities of U.S. production, consumption, trade, stocks, and prices for petroleum, natural gas, coal, electricity, and nuclear energy. Also included are international energy and thermal and metric conversion factors.

  12. Landscaping for energy efficiency

    SciTech Connect

    1995-04-01

    This publication by the National Renewable Energy Laboratory addresses the use of landscaping for energy efficiency. The topics of the publication include minimizing energy expenses; landscaping for a cleaner environment; climate, site, and design considerations; planning landscape; and selecting and planting trees and shrubs. A source list for more information on landscaping for energy efficiency and a reading list are included.

  13. Energy 101: Electric Vehicles

    SciTech Connect

    2012-01-01

    This edition of Energy 101 highlights the benefits of electric vehicles, including improved fuel efficiency, reduced emissions, and lower maintenance costs. For more information on electric vehicles from the Office of Energy Efficiency and Renewable Energy, visit the Vehicle Technologies Program website: http://www1.eere.energy.gov/vehiclesandfuels/

  14. Profiles in Energy.

    ERIC Educational Resources Information Center

    National Council for Resource Development, Washington, DC.

    In order to assist two-year college educators in increasing their participation in energy-related activities, this publication provides guidelines for planning energy projects and descriptions of model energy programs. The steps outlined for program planning include the assessment of area energy resources, the identification of local…

  15. Solar Energy: Heat Transfer.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on heat transfer is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The…

  16. The Household Energy Game.

    ERIC Educational Resources Information Center

    Smith, Thomas W.; Jenkins, John

    The Household Energy Game has been developed to provide some indication of energy use and individual management. The game is divided into two sections. In the first section, one is to devise one's own energy budget. Energy use is calculated in the areas of transportation, heating, hot water, air conditioning, and appliances. In each of these major…

  17. Home energy saver's handbook

    NASA Astrophysics Data System (ADS)

    Koga, N. N.

    1980-09-01

    Energy is described and how much energy a household consumes is discussed. The saving of energy is recommended and measures to save energy when operating hot water heaters, air conditioners, lighting systems refrigerators, freezers, stoves, microwave ovens, washing machines, clothes dryers, dishwashers, television sets, and portable appliances are summarized.

  18. The Carter Energy Plan

    ERIC Educational Resources Information Center

    Coan, Gene

    1977-01-01

    Plans for the implementation of a national energy policy are outlined. Proposed measures in the following areas are discussed: energy conservation; energy systems and rates; energy pricing and equity; coal, oil and gas production; nuclear and solar power; and industry structure and competition. Concerns of environmentalists are expressed. (AJ)

  19. Evaluating Energy Conversion Efficiency

    NASA Technical Reports Server (NTRS)

    Byvik, C. E.; Smith, B. T.; Buoncristiani, A. M.

    1983-01-01

    Devices that convert solar radiation directly into storable chemical or electrical energy, have characteristic energy absorption spectrum; specifically, each of these devices has energy threshold. The conversion efficiency of generalized system that emcompasses all threshold devices is analyzed, resulting in family of curves for devices of various threshold energies operating at different temperatures.

  20. Energy: Options and Issues.

    ERIC Educational Resources Information Center

    Walker, Harry O.

    This book is intended to provide basic information about energy. The first three chapters describe energy supply and demand, uses and sources, and common energy terms. The next two chapters explain environmental and biological effects of energy systems. Twelve chapters that follow outline past history and technological knowledge of the following…

  1. Energy Facts 1988.

    ERIC Educational Resources Information Center

    Energy Information Administration (DOE), Washington, DC.

    This booklet is a compilation of energy data providing a reference to a much broader range of domestic and international energy data. It is designed especially as a quick reference to major facts about energy. The data includes information for 1976 through 1988, except for international energy data, which is for 1977 through 1987. Graphs, charts,…

  2. Zero Energy Use School.

    ERIC Educational Resources Information Center

    Nelson, Brian, Ed.; And Others

    The economic and physical realities of an energy shortage have caused many educators to consider alternative sources of energy when constructing their schools. This book contains studies and designs by fifth-year architecture students concerning the proposed construction of a zero energy-use elementary school in Albany, Oregon. "Zero energy use"…

  3. Energy Options for Man.

    ERIC Educational Resources Information Center

    Tratner, Karen Lee

    Produced for public interest, the Environmental Education Group has prepared this two-part review of the current state of energy utilization, the nature of the energy crisis, and approaches to energy production. The major section is a presentation of alternative sources of energy that are neglected, are of possible aid in the near future, or are…

  4. Energy 101: Electric Vehicles

    ScienceCinema

    None

    2013-05-29

    This edition of Energy 101 highlights the benefits of electric vehicles, including improved fuel efficiency, reduced emissions, and lower maintenance costs. For more information on electric vehicles from the Office of Energy Efficiency and Renewable Energy, visit the Vehicle Technologies Program website: http://www1.eere.energy.gov/vehiclesandfuels/

  5. Solar Energy: Heat Storage.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on heat storage is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  6. Solar Energy: Home Heating.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on home heating is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  7. Radiant energy collector

    DOEpatents

    Winston, Roland

    1977-01-11

    An electromagnetic energy collection device is provided which does not require a solar tracking capability. It includes an energy receiver positioned between two side walls which reflect substantially all incident energy received over a predetermined included angle directly onto the energy receiver.

  8. Energy 101: Energy Efficient Data Centers

    SciTech Connect

    2011-01-01

    Data centers provide mission-critical computing functions vital to the daily operation of top U.S. economic, scientific, and technological organizations. These data centers consume large amounts of energy to run and maintain their computer systems, servers, and associated high-performance components—up to 3% of all U.S. electricity powers data centers. And as more information comes online, data centers will consume even more energy. Data centers can become more energy efficient by incorporating features like power-saving "stand-by" modes, energy monitoring software, and efficient cooling systems instead of energy-intensive air conditioners. These and other efficiency improvements to data centers can produce significant energy savings, reduce the load on the electric grid, and help protect the nation by increasing the reliability of critical computer operations.

  9. National Energy Act statutes and solar energy

    SciTech Connect

    Howard, J.

    1980-02-01

    The National Energy Act of 1978 contains many provisions that will significantly affect solar technology commercialization and solar energy users. Four of the five statutes that comprise the National Energy Act deserve close attention. The National Energy Conservation Policy Act will promote residential solar installations. The Energy Tax Act will accelerate both residential and commercial solar system applications. The Public Utilities Regulatory Policies Act promotes efficient use of utility resources as well as decentralized power production. And, the Power Plan and Industrial Fuel Use Act places severe restrictions on future burning of petroleum and natural gas, which should lead some operators to build or convert to solar energy systems. Each of the preceding acts are considered in separate sections of this report. Federal regulations issued pursuant to the various provisions are also identified and discussed, and some of the problems with the provisions and regulations are noted.

  10. Energy 101: Energy Efficient Data Centers

    ScienceCinema

    None

    2013-05-29

    Data centers provide mission-critical computing functions vital to the daily operation of top U.S. economic, scientific, and technological organizations. These data centers consume large amounts of energy to run and maintain their computer systems, servers, and associated high-performance components?up to 3% of all U.S. electricity powers data centers. And as more information comes online, data centers will consume even more energy. Data centers can become more energy efficient by incorporating features like power-saving "stand-by" modes, energy monitoring software, and efficient cooling systems instead of energy-intensive air conditioners. These and other efficiency improvements to data centers can produce significant energy savings, reduce the load on the electric grid, and help protect the nation by increasing the reliability of critical computer operations.

  11. Energy Efficiency and Renewable Energy Program

    NASA Astrophysics Data System (ADS)

    Vaughan, K. H.

    1993-06-01

    The bibliography contains listings of publicly available reports, journal articles, and published conference papers sponsored by the DOE Office of Energy Efficiency and Renewable Energy and published between 1987 and mid-1993. The topics of the bibliography include: analysis and evaluation; building equipment research; building thermal envelope systems and materials; district heating; residential and commercial conservation program; weatherization assistance program; existing buildings research program; ceramic technology project; alternative fuels and propulsion technology; microemulsion fuels; industrial chemical heat pumps; materials for advanced industrial heat exchangers; advanced industrial materials; tribology; energy-related inventions program; electric energy systems; superconducting technology program for electric energy systems; thermal energy storage; biofuels feedstock development; biotechnology; continuous chromatography in multicomponent separations; sensors for electrolytic cells; hydropower environmental mitigation; environmental control technology; and continuous fiber ceramic composite technology.

  12. Energy Week presentations

    SciTech Connect

    2006-07-01

    Topics covered include: energy security; clean energy and low carbon; energy for growth and poverty reduction in Africa; financing of energy efficiency; SMEs for decentralised energy service provision; potential for biofuels in developing countries; clean energy and sustainable development; clean energy finance and private equity funds; power generation and low carbon technologies; beyond traditional finance; rehabilitation and emission control in thermal power plants; and carbon finance. The presentations are mainly in ppt (Power Point) or pdf (Acrobat) format. Some videos of the conference are also available on the website.

  13. Annual Energy Review 2010

    SciTech Connect

    2011-10-01

    This twenty-ninth edition of the Annual Energy Review (AER) presents the U.S. Energy Information Administration’s (EIA) most comprehensive look at integrated energy statistics. The summary statistics on the Nation’s energy production, consumption, trade, stocks, and prices cover all major energy commodities and all energy-consuming sectors of the U.S. economy from 1949 through 2010. The AER is EIA’s historical record of energy statistics and, because the coverage spans six decades, the statistics in this report are well-suited to long-term trend analysis.

  14. China Energy Primer

    SciTech Connect

    Ni, Chun Chun

    2009-11-16

    Based on extensive analysis of the 'China Energy Databook Version 7' (October 2008) this Primer for China's Energy Industry draws a broad picture of China's energy industry with the two goals of helping users read and interpret the data presented in the 'China Energy Databook' and understand the historical evolution of China's energy inustry. Primer provides comprehensive historical reviews of China's energy industry including its supply and demand, exports and imports, investments, environment, and most importantly, its complicated pricing system, a key element in the analysis of China's energy sector.

  15. World energy resources

    NASA Astrophysics Data System (ADS)

    Clerici, A.; Alimonti, G.

    2015-08-01

    As energy is the main "fuel" for social and economic development and since energy-related activities have significant environmental impacts, it is important for decision-makers to have access to reliable and accurate data in an user-friendly format. The World Energy Council (WEC) has for decades been a pioneer in the field of energy resources and every three years publishes its flagship report Survey of Energy Resources. A commented analysis in the light of latest data summarized in such a report, World Energy Resources (WER) 2013, is presented together with the evolution of the world energy resources over the last twenty years.

  16. Renewable energy annual 1996

    SciTech Connect

    1997-03-01

    This report presents summary data on renewable energy consumption, the status of each of the primary renewable technologies, a profile of each of the associated industries, an analysis of topical issues related to renewable energy, and information on renewable energy projects worldwide. It is the second in a series of annual reports on renewable energy. The renewable energy resources included in the report are biomass (wood and ethanol); municipal solid waste, including waste-to-energy and landfill gas; geothermal; wind; and solar energy, including solar thermal and photovoltaic. The report also includes various appendices and a glossary.

  17. Energy Conservation Simplified

    NASA Astrophysics Data System (ADS)

    Hecht, Eugene

    2008-02-01

    The standard formulation of energy conservation involves the subsidiary ideas of kinetic energy (KE), work (W), thermal energy, internal energy, and a half-dozen different kinds of potential energy (PE): elastic, chemical, nuclear, gravitational, and so forth. These quantities came to be recognized during the centuries over which the principle developed. The final conservation law, although rich in specificity, is fairly involved. More significantly, it obscures a fundamental underlying simplicity, which could only be appreciated post-relativity (1905). Energy is the scalar measure of physical change. Using the special theory it will be shown that there are only two all-encompassing classifications of energy—energy of rest and energy of motion—and that we can apply the idea of conservation of energy to all physical processes using only these two energy types as quantified by mass and KE.

  18. Energy Tracking Software Platform

    SciTech Connect

    Ryan Davis; Nathan Bird; Rebecca Birx; Hal Knowles

    2011-04-04

    Acceleration has created an interactive energy tracking and visualization platform that supports decreasing electric, water, and gas usage. Homeowners have access to tools that allow them to gauge their use and track progress toward a smaller energy footprint. Real estate agents have access to consumption data, allowing for sharing a comparison with potential home buyers. Home builders have the opportunity to compare their neighborhood's energy efficiency with competitors. Home energy raters have a tool for gauging the progress of their clients after efficiency changes. And, social groups are able to help encourage members to reduce their energy bills and help their environment. EnergyIT.com is the business umbrella for all energy tracking solutions and is designed to provide information about our energy tracking software and promote sales. CompareAndConserve.com (Gainesville-Green.com) helps homeowners conserve energy through education and competition. ToolsForTenants.com helps renters factor energy usage into their housing decisions.

  19. Great Lakes Energy Institute

    SciTech Connect

    Alexander, J. Iwan

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  20. Solar energy emplacement developer

    NASA Technical Reports Server (NTRS)

    Mortensen, Michael; Sauls, Bob

    1991-01-01

    A preliminary design was developed for a Lunar Power System (LPS) composed of photovoltaic arrays and microwave reflectors fabricated from lunar materials. The LPS will collect solar energy on the surface of the Moon, transform it into microwave energy, and beam it back to Earth where it will be converted into usable energy. The Solar Energy Emplacement Developer (SEED) proposed will use a similar sort of solar energy collection and dispersement to power the systems that will construct the LPS.

  1. International energy outlook 2006

    SciTech Connect

    2006-06-15

    This report presents international energy projections through 2030, prepared by the Energy Information Administration. After a chapter entitled 'Highlights', the report begins with a review of world energy and economic outlook, followed by energy consumption by end-use sector. The next chapter is on world oil markets. Natural gas, world coal market and electricity consumption and supply are then discussed. The final chapter covers energy-related carbon dioxide emissions.

  2. Module two: energy utilization

    SciTech Connect

    Not Available

    1980-01-01

    This report contains a teaching module for presentation at the junior college level. A shortened version can also be presented to civic groups or high school vocational classes. Energy use in the past is contrasted with present energy use in 3 sectors: business, industry and the home. The module explains specifically the changes in energy sources and outlines energy use, the need for, and methods of conservation of energy in these 3 sections. 29 references, 7 figures. (DMC)

  3. Programs in Renewable Energy

    NASA Astrophysics Data System (ADS)

    1990-01-01

    Our nation faces significant challenges as we enter the 1990s: securing a reliable supply of competitively priced energy, improving the quality of our environment, and increasing our share of foreign markets for goods and services. The U.S. Department of Energy's (DOE) Programs in Renewable Energy are working toward meeting these challenges by developing the technologies that make use of our nation's largest energy resource: renewable energy. The sunlight, wind biomass, flowing water, ocean energy, and geothermal energy that make up the renewable energy resource can be found throughout our nation. These resources can provide all the forms of energy our nation needs: liquid fuels, electricity, and heating and cooling. Renewable energy meets about 10 percent of our need for these forms of energy today, yet the potential contribution is many times greater. DOE's Programs in Renewable Energy are working side-by-side with American industry to develop the technologies that convert renewable energy resources into practical, cost-competitive energy. After a decade of progress in research, several of these technologies are poised to make large contributions during the 1990s and beyond. This booklet provides an overview of the renewable energy programs and their plans for FY 1990. Sources of additional information are listed at the back of the booklet.

  4. Energy Tracking Diagrams

    NASA Astrophysics Data System (ADS)

    Scherr, Rachel E.; Harrer, Benedikt W.; Close, Hunter G.; Daane, Abigail R.; DeWater, Lezlie S.; Robertson, Amy D.; Seeley, Lane; Vokos, Stamatis

    2016-02-01

    Energy is a crosscutting concept in science and features prominently in national science education documents. In the Next Generation Science Standards, the primary conceptual learning goal is for learners to conserve energy as they track the transfers and transformations of energy within, into, or out of the system of interest in complex physical processes. As part of tracking energy transfers among objects, learners should (i) distinguish energy from matter, including recognizing that energy flow does not uniformly align with the movement of matter, and should (ii) identify specific mechanisms by which energy is transferred among objects, such as mechanical work and thermal conduction. As part of tracking energy transformations within objects, learners should (iii) associate specific forms with specific models and indicators (e.g., kinetic energy with speed and/or coordinated motion of molecules, thermal energy with random molecular motion and/or temperature) and (iv) identify specific mechanisms by which energy is converted from one form to another, such as incandescence and metabolism. Eventually, we may hope for learners to be able to optimize systems to maximize some energy transfers and transformations and minimize others, subject to constraints based in both imputed mechanism (e.g., objects must have motion energy in order for gravitational energy to change) and the second law of thermodynamics (e.g., heating is irreversible). We hypothesize that a subsequent goal of energy learning—innovating to meet socially relevant needs—depends crucially on the extent to which these goals have been met.

  5. Programs in Renewable Energy

    SciTech Connect

    Not Available

    1990-01-01

    Our nation faces significant challenges as we enter the 1990s: securing a reliable supply of competitively priced energy, improving the quality of our environment, and increasing our share of foreign markets for goods and services. The US Department of Energy's (DOE) Programs in Renewable Energy are working toward meeting these challenges by developing the technologies that make use of our nation's largest energy resource: renewable energy. The sunlight, wind biomass, flowing water, ocean energy, and geothermal energy that make up the renewable energy resource can be found throughout our nation. These resources can provide all the forms of energy our nation needs: liquid fuels, electricity, and heating and cooling. Renewable energy meets about 10% of our need for these forms of energy today, yet the potential contribution is many times greater. DOE's Programs in Renewable Energy are working side-by-side with American industry to develop the technologies that convert renewable energy resources into practical, cost-competitive energy. After a decade of progress in research, several of these technologies are poised to make large contributions during the 1990s and beyond. This booklet provides an overview of the renewable energy programs and their plans for FY 1990. Sources of additional information are listed at the back of the booklet. 48 figs., 4 tabs.

  6. NANA Strategic Energy Plan & Energy Options Analysis

    SciTech Connect

    Jay Hermanson; Brian Yanity

    2008-12-31

    NANA Strategic Energy Plan summary NRC, as an Alaska Native Corporation, has committed to addressing the energy needs for its shareholders. The project framework calls for implicit involvement of the IRA Councils in the Steering Committee. Tribal Members, from the NRC to individual communities, will be involved in development of the NANA Energy Plan. NRC, as the lead tribal entity, will serve as the project director of the proposed effort. The NRC team has communicated with various governmental and policy stakeholders via meetings and discussions, including Denali Commission, Alaska Energy Authority, and other governmental stakeholders. Work sessions have been initiated with the Alaska Village Electric Cooperative, the NW Arctic Borough, and Kotzebue Electric Association. The NRC Strategic Energy Plan (SEP) Steering committee met monthly through April and May and weekly starting in June 2008 in preparation of the energy summit that was held from July 29-31, 2008. During preparations for the energy summit and afterwards, there was follow through and development of project concepts for consideration. The NANA regional energy summit was held from July 29-31, 2008, and brought together people from all communities of the Northwest Arctic Borough. The effort was planned in conjunction with the Alaska Energy Authority’s state-wide energy planning efforts. Over $80,000 in cash contributions was collected from various donors to assist with travel from communities and to develop the summit project. Available funding resources have been identified and requirements reviewed, including the Denali Commission, U.S. Dept. of Agriculture, and the Alaska Energy Authority. A component of the overall plan will be a discussion of energy funding and financing. There are current project concepts submitted, or are ready for submittal, in the region for the following areas: • Wind-diesel in Deering, Buckland, Noorik, and Kiana areas; potential development around Red Dog mine.

  7. 75 FR 70214 - Renewable Energy and Energy Efficiency Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... International Trade Administration Renewable Energy and Energy Efficiency Advisory Committee AGENCY... Renewable Energy and Energy Efficiency Advisory Committee (RE&EEAC) will hold its inaugural meeting to..., Office of Energy and Environmental Technologies Industries (OEEI), International Trade Administration,...

  8. 78 FR 48855 - Renewable Energy and Energy Efficiency Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-12

    ...; ] DEPARTMENT OF COMMERCE International Trade Administration Renewable Energy and Energy Efficiency Advisory... Meeting. SUMMARY: The Renewable Energy and Energy Efficiency Advisory Committee (RE&EEAC) will hold a...: Ryan Mulholland, Office of Energy and Environmental Industries (OEEI), International...

  9. Science Activities in Energy: Wind Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Included in this science activities energy package are 12 activities related to wind energy for elementary students. Each activity is outlined on a single card and is introduced by a question. Topics include: (1) At what time of day is there enough wind to make electricity where you live?; (2) Where is the windiest spot on your schoolground?; and…

  10. Energy Conservation. CORD Energy Technology Series.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This course in energy conservation is one of 16 courses in the Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in company-sponsored training programs. Comprised of seven modules,…

  11. Annual Energy Review 2007

    SciTech Connect

    Seiferlein, Katherine E.

    2008-06-01

    The Annual Energy Review (AER) is the Energy Information Administration's (EIA) primary report of annual historical energy statistics. For many series, data begin with the year 1949. Included are data on total energy production, consumption, and trade; overviews of petroleum, natural gas, coal, electricity, nuclear energy, renewable energy, international energy, as well as financial and environment indicators; and data unit conversion tables. Publication of this report is required under Public Law 95–91 (Department of Energy Organization Act), Section 205(c), and is in keeping with responsibilities given to the EIA under Section 205(a)(2), which states: “The Administrator shall be responsible for carrying out a central, comprehensive, and unified energy data and information program which will collect, evaluate, assemble, analyze, and disseminate data and information....”

  12. Prospects for Sustainable Energy

    NASA Astrophysics Data System (ADS)

    Cassedy, Edward S., Jr.

    2000-04-01

    Fossil fuels are a finite resource, and their continued use as the world's dominant energy supply is damaging the environment. Future use of alternative methods of energy supply is inescapable. This book offers a critical assessment of all possible sustainable energy technologies and energy storage. Coverage explores the historical origins, technical features, marketability, and environmental impacts of the complete range of sustainable energy technologies: solar, biomass, wind, hydropower, geothermal power, ocean-energy sources, solar-derived hydrogen fuel, and energy storage. The aim is to inform policy analysts and decision makers of the options available for sustainable energy production. This accessible volume will be a valuable resource for a broad group of academics and researchers with a wide range of backgrounds and scientific training. It will also be an ideal supplementary next for advanced courses in environmental studies, energy economics and policy, and engineering.

  13. Nonimaging radiant energy device

    DOEpatents

    Winston, Roland; Ning, Xiaohui

    1993-01-01

    A nonimaging radiant energy device may include a hyperbolically shaped reflective element with a radiant energy inlet and a radiant energy outlet. A convex lens is provided at the radiant energy inlet and a concave lens is provided at the radiant energy outlet. Due to the provision of the lenses and the shape of the walls of the reflective element, the radiant energy incident at the radiant energy inlet within a predetermined angle of acceptance is emitted from the radiant energy outlet exclusively within an acute exit angle. In another embodiment, the radiant energy device may include two interconnected hyperbolically shaped reflective elements with a respective convex lens being provided at each aperture of the device.

  14. Nonimaging radiant energy device

    DOEpatents

    Winston, Roland; Ning, Xiaohui

    1996-01-01

    A nonimaging radiant energy device may include a hyperbolically shaped reflective element with a radiant energy inlet and a radiant energy outlet. A convex lens is provided at the radiant energy inlet and a concave lens is provided at the radiant energy outlet. Due to the provision of the lenses and the shape of the walls of the reflective element, the radiant energy incident at the radiant energy inlet within a predetermined angle of acceptance is emitted from the radiant energy outlet exclusively within an acute exit angle. In another embodiment, the radiant energy device may include two interconnected hyperbolically shaped reflective elements with a respective convex lens being provided at each aperture of the device.

  15. Energy rays tracking device

    SciTech Connect

    Monk, R.J.

    1981-05-12

    An energy rays tracking device includes a receiver for fixing a position relative to the direction of maximum energy rays, a prime mover for maintaining the alignment of the receiver and an energy rays user, an energy rays tracker for controlling the power to the prime mover in response to the receiver, a timed tracker for controlling the prime mover when the energy rays tracker is not functioning due to energy rays being too diffused, an energy sensitive element for detecting the presence or absence of energy rays, and a power controller responsive to the energy sensitive element for repositioning the receiver and the energy rays user for the following period of tracking is disclosed. The receiver includes an enclosure which only allows a selected pattern of direct rays to penetrate into the enclosure. A razor sharp edge at the opening of the enclosure maintains the outermost direct energy rays undiffused. A differential sensor sensitive to direct energy rays is installed inside the enclosure for determining the direction of the direct energy rays. In an application for tracking the sun, the time tracker uses a piecewise linear method of tracking. In the return cycle during the night, the return is interspersed with a wash cycle for cleaning the energy rays user.

  16. Monthly energy review, February 1997

    SciTech Connect

    1997-02-01

    This is an overview of the February energy statistics by the Energy Information Administration. The contents of the report include an energy overview, US energy production, energy consumption, trade stocks and prices for petroleum, natural gas, oil and gas resource development, coal, electricity, nuclear energy, energy prices, and international energy. 37 figs., 73 tabs.

  17. Energy for America's Third Century

    ERIC Educational Resources Information Center

    MOSAIC, 1974

    1974-01-01

    Six articles concerned with energy use, energy research and sources of energy are included in this issue. Articles are titled (1) Energy Systems; (2) Energy-Related Research; (3) Solar Energy; (4) Geothermal Energy; (5) Coal; and (6) Utilization of Energy. (RH)

  18. Monthly energy review, January 1997

    SciTech Connect

    1997-01-01

    This is an overview of the January energy statistics by the Energy Information Administration. The contents of the report include an energy overview, US energy production, energy consumption, trade stocks and prices for petroleum, natural gas, oil and gas resource development, coal, electricity, nuclear energy, energy prices, and international energy. 47 figs., 71 tabs.

  19. Radiant energy to electric energy converter

    NASA Technical Reports Server (NTRS)

    Sher, Arden (Inventor)

    1980-01-01

    Radiant energy is converted into electric energy by irradiating a capacitor including an ionic dielectric. The dielectric is a sintered crystal superionic conductor, e.g., lanthanum trifluoride, lanthanum trichloride, or silver bromide, so that a multiplicity of crystallites exist between electrodes of the capacitor. The radiant energy cyclically irradiates the dielectric so that the dielectric exhibits a cyclic photocapacitive like effect. Adjacent crystallites have abutting surfaces that enable the crystallites to effectively form a multiplicity of series capacitor elements between the electrodes. Each of the capacitor elements has a dipole layer only on or near its surface. The capacitor is initially charged to a voltage just below the dielectric breakdown voltage by connecting it across a DC source causing a current to flow through a charging resistor to the dielectric. The device can be utilized as a radiant energy detector or as a solar energy cell.

  20. Home Energy Assessments

    SciTech Connect

    Dispenza, Jason

    2010-01-01

    A home energy assessment, also known as a home energy audit, is the first step to assess how much energy your home consumes and to evaluate what measures you can take to make your home more energy efficient. An assessment will show you problems that may, when corrected, save you significant amounts of money over time. This video shows some of the ways that a contractor may test your home during an assessment, and helps you understand how an assessment can help you move toward energy savings. Find out more at: http://www.energysavers.gov/your_home/energy_audits/index.cfm/mytopic=11160

  1. Home Energy Assessments

    ScienceCinema

    Dispenza, Jason

    2013-05-29

    A home energy assessment, also known as a home energy audit, is the first step to assess how much energy your home consumes and to evaluate what measures you can take to make your home more energy efficient. An assessment will show you problems that may, when corrected, save you significant amounts of money over time. This video shows some of the ways that a contractor may test your home during an assessment, and helps you understand how an assessment can help you move toward energy savings. Find out more at: http://www.energysavers.gov/your_home/energy_audits/index.cfm/mytopic=11160

  2. The Global Energy Challenge

    ScienceCinema

    Crabtree, George

    2010-01-08

    The expected doubling of global energy demand by 2050 challenges our traditional patterns of energy production, distribution and use.   The continued use of fossil fuels raises concerns about supply, security, environment and climate.  New routes are needed for the efficient conversion of energy from chemical fuel, sunlight, and heat to electricity or hydrogen as an energy carrier and finally to end uses like transportation, lighting, and heating. Opportunities for efficient new energy conversion routes based on nanoscale materials will be presented, with emphasis on the sustainable energy technologies they enable.

  3. Alaska's renewable energy potential.

    SciTech Connect

    Not Available

    2009-02-01

    This paper delivers a brief survey of renewable energy technologies applicable to Alaska's climate, latitude, geography, and geology. We first identify Alaska's natural renewable energy resources and which renewable energy technologies would be most productive. e survey the current state of renewable energy technologies and research efforts within the U.S. and, where appropriate, internationally. We also present information on the current state of Alaska's renewable energy assets, incentives, and commercial enterprises. Finally, we escribe places where research efforts at Sandia National Laboratories could assist the state of Alaska with its renewable energy technology investment efforts.

  4. Thermal energy storage

    SciTech Connect

    Tomlinson, J.J. ); Kannberg, L.D. )

    1990-09-01

    This paper discusses how thermal energy storage (TES) can aid in the efficient use and provision of thermal energy, wherever there is a mismatch between energy generation and use. Three fundamental types of thermal energy storage processes (sensible, latent, and thermochemical) can be used, and many different media are available within each type. Various subsets of these processes are being researched and developed to accelerate TES implementation, focusing on applications in building heating and cooling, industrial energy efficiency, and utility and space power systems. TES can contribute significantly to meeting society's needs for more efficient, environmentally benign energy use in these and other sectors.

  5. International energy annual 1996

    SciTech Connect

    1998-02-01

    The International Energy Annual presents an overview of key international energy trends for production, consumption, imports, and exports of primary energy commodities in over 220 countries, dependencies, and areas of special sovereignty. Also included are population and gross domestic product data, as well as prices for crude oil and petroleum products in selected countries. Renewable energy reported in the International Energy Annual includes hydroelectric power, geothermal, solar, and wind electric power, biofuels energy for the US, and biofuels electric power for Brazil. New in the 1996 edition are estimates of carbon dioxide emissions from the consumption of petroleum and coal, and the consumption and flaring of natural gas. 72 tabs.

  6. Energy consumption in manufacturing

    NASA Astrophysics Data System (ADS)

    Schmid, S. R.

    2012-04-01

    Energy sources, in the form of coal, oil, natural gas, solar or nuclear power, are global commodities, and as demand is projected to rise in the coming decades, so will costs. As such, an understanding of the energy needs of manufacturing processes and the ability to reduce the energy and carbon footprints are essential for sustainability reasons. Energy source effects are quantified in a number of measures. Models of energy needs by manufacturing processes are then examined, along with models incorporating the use of ancillary equipment such as pumps, filters, blowers, lighting, etc. Finally, the successful application of the tribological principles to influence energy consumption is discussed.

  7. Wind energy bibliography

    SciTech Connect

    1995-05-01

    This bibliography is designed to help the reader search for information on wind energy. The bibliography is intended to help several audiences, including engineers and scientists who may be unfamiliar with a particular aspect of wind energy, university researchers who are interested in this field, manufacturers who want to learn more about specific wind topics, and librarians who provide information to their clients. Topics covered range from the history of wind energy use to advanced wind turbine design. References for wind energy economics, the wind energy resource, and environmental and institutional issues related to wind energy are also included.

  8. Energy and resource consumption

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The present and projected energy requirements for the United States are discussed. The energy consumption and demand sectors are divided into the categories: residential and commercial, transportation, and industrial and electrical generation (utilities). All sectors except electrical generation use varying amounts of fossile fuel resources for non-energy purposes. The highest percentage of non-energy use by sector is industrial with 71.3 percent. The household and commercial sector uses 28.4 percent, and transportation about 0.3 percent. Graphs are developed to project fossil fuel demands for non-energy purposes and the perdentage of the total fossil fuel used for non-energy needs.

  9. The Global Energy Challenge

    SciTech Connect

    Crabtree, George

    2007-09-12

    The expected doubling of global energy demand by 2050 challenges our traditional patterns of energy production, distribution and use.   The continued use of fossil fuels raises concerns about supply, security, environment and climate.  New routes are needed for the efficient conversion of energy from chemical fuel, sunlight, and heat to electricity or hydrogen as an energy carrier and finally to end uses like transportation, lighting, and heating. Opportunities for efficient new energy conversion routes based on nanoscale materials will be presented, with emphasis on the sustainable energy technologies they enable.

  10. State Energy Program in Kentucky

    SciTech Connect

    Not Available

    2003-04-01

    The State Energy Program in Kentucky summarizes the important renewable energy and energy efficiency projects and recent successes of the Kentucky Division of Energy, which is the state energy office in the Kentucky.

  11. Monthly energy review, August 1993

    SciTech Connect

    Not Available

    1993-08-26

    This publication presents information for the month of August, 1993 on the following: Energy overview; energy consumption; petroleum; natural gas; oil and gas resource development; coal; electricity; nuclear energy; energy prices, and international energy.

  12. Special Report: Energy

    ERIC Educational Resources Information Center

    Cuscaden, Rob

    1976-01-01

    Presently available design techniques, technologies, and management practices can significantly reduce the energy requirements of new buildings. A two-part section discusses solutions to the energy problem in the commercial, institutional, and industrial fields. (Author/MLF)

  13. Plugging the Energy Sieve

    ERIC Educational Resources Information Center

    Rubin, Milton D.

    1974-01-01

    Attempts to show the feasibility of an energy conservation policy based on a greatly improved efficiency of use of energy. Considers efficiency in the industrial, residential, commercial, and transporation sectors. (GS)

  14. Introduction to Energy

    NASA Astrophysics Data System (ADS)

    Cassedy, Edward S.; Grossman, Peter Z.

    1999-01-01

    Energy issues such as pollution, resource depletion, global warming, nuclear power and waste are problems demanding timely solutions. This book provides a critical examination of the resources, market forces, and social impacts of modern energy production. The book addresses the dilemmas that have arisen due to society's crucial dependence on energy, particularly fossil fuels, and explores the available alternative energy producing technologies. The second edition has increased emphasis on those issues at the forefront of the current energy debate: energy sustainability, climate change, and the radical restructuring of the power industry due to deregulation. Assuming no prior technical expertise and avoiding complex mathematical formulation. The second edition, like the first, will be especially useful as a textbook for undergraduate programs in Science, Technology and Society (STS), and as a supplementary text in a variety of courses that touch on energy studies, including environmental and technology policy, environmental, mineral and business law, energy and resource economics.

  15. The goldstone energy project

    NASA Technical Reports Server (NTRS)

    Bartos, K. P.

    1978-01-01

    The Golstone Energy Project was established in 1974 to investigate ways in which the Goldstone Deep Space Complex in California could be made partly or completely energy-sufficient, especially through the use of solar- and wind-derived energy resources. Ways in which energy could be conserved at the Complex were also studied. Findings included data on both wind and solar energy. Obstacles to demonstrating energy self-sufficiency are: (1) operation and maintenance costs of solar energy systems are estimated to be much higher than conventional energy systems, (2) initial capital costs of present-day technology solar collectors are high and are compounded by low collector efficiency, and (3) no significant market force exists to create the necessary industry to reduce costs through mass production and broad open-market competition.

  16. Industrial energy conservation technology

    SciTech Connect

    Schmidt, P.S.; Williams, M.A.

    1980-01-01

    A separate abstract was prepared for each of the 60 papers included in this volume, all of which will appear in Energy Research Abstracts (ERA); 21 were selected for Energy Abstracts for Policy Analysis (EAPA). (MCW)

  17. Energy design for architects

    SciTech Connect

    Shaw, A.

    1989-01-01

    This book contains techniques for energy efficiency in architectural design. Many aspects are covered including: cost; comfort and health; energy use; the design process; and analytical techniques. 202 figs. (JF)

  18. The energy quandary

    SciTech Connect

    LePori, W.A. )

    1991-03-01

    As the war in the Middle East draws attention to energy needs, agricultural engineers will have the opportunity to contribute to a rational energy use policy. Even before the war, changes were occurring that pointed to the need for reviewing energy use in agriculture. A new consciousness of environmental problems is arising in the US. Many changes such as recycling, new pesticide regulations, more stringent air and water quality standards, new food quality standards, and others will directly impact energy use within the food and fiber producing industries. Energy issues should be addressed simultaneously with environmental issues. In the past, agricultural engineers have responded and provided significant contributions to help assure agriculture's energy needs. Their participation and input is again vital to assure availability of adequate energy for agriculture and development of energy resources from agriculture.

  19. Energy for Planet Earth.

    ERIC Educational Resources Information Center

    Davis, Ged R.

    1990-01-01

    Examined is the world society's ability to meet energy needs without destroying the earth. Supply and demand issues are examined. International per capita energy use is compared. Historical trends are described. (CW)

  20. Energy of an Astronaut

    NASA Video Gallery

    Where does the energy of a space explorer come from? Find out about caloric intake, energy needs, and the metabolism inside the human space explorer's body by testing for starch with flour tortilla...

  1. Global space fusion energy

    NASA Astrophysics Data System (ADS)

    Latyshev, L. A.; Semashko, N. N.

    The possibility of meeting future global energy demands by producing energy in space is addressed. Comparisons are made between the parameters of space plants producing solar electric power, nuclear electric power, and thermonuclear electric power.

  2. Tapping The Sun's Energy

    ERIC Educational Resources Information Center

    Lee, David G.

    1974-01-01

    Describes several successful attempts to utilize solar energy for heating and providing electrical energy for homes. Indicates that more research and development are needed, especially in the area of large scale usage. (SLH)

  3. NASA and energy

    NASA Technical Reports Server (NTRS)

    1974-01-01

    NASA technology contributions to create energy sources include direct solar heating and cooling systems, wind generation of electricity, solar thermal energy turbine drives, solar cells, and techniques for locating, producing, and collecting organic materials for conversion into fuel.

  4. Federal Energy Information Systems.

    ERIC Educational Resources Information Center

    Coyne, Joseph G.; Moneyhun, Dora H.

    1979-01-01

    Describes the Energy Information Administration (EIA) and the Technical Information Center (TIC), and lists databases accessible online to the Department of Energy and its contractors through DOE/RECON. (RAA)

  5. Air transportation energy efficiency

    NASA Technical Reports Server (NTRS)

    Williams, L. J.

    1977-01-01

    The energy efficiency of air transportation, results of the recently completed RECAT studies on improvement alternatives, and the NASA Aircraft Energy Efficiency Research Program to develop the technology for significant improvements in future aircraft were reviewed.

  6. Renewable energy technology characterizations

    SciTech Connect

    None, None

    1997-12-01

    The Renewable Energy Technology Characterizations front matter lists the chapters and tables that support this report on the technical and economic status of the major emerging renewable energy options for electricity supply.

  7. Foundry energy conservation workbook

    SciTech Connect

    Not Available

    1990-01-01

    The foundry industry is a significant user of energy, and therefore, a natural candidate for efforts to save energy and improve efficiency by both governmental agencies and technical/trade associations. These efforts are designed to both improve the national energy position and improve the industry's efficiency and profitability. Increased energy cost and the reduced availability of fossil fuels at certain times have provided the incentive to curb waste and to utilize purchased energy wisely. Energy costs now approach and sometimes exceed 10% of the sales dollar of many foundries. Although energy use by foundries has gradually decreased on a per/ton basis in recent years, the foundry industry must continue to find ways to utilize energy more efficiently. This workbook provides ways to achieve this goal.

  8. Teaching about Energy.

    ERIC Educational Resources Information Center

    Schlene, Vickie J.

    1992-01-01

    Provides a partial listing of documents from the ERIC database dealing with energy. Includes information on natural resources, curriculum planning, and energy development. Suggests available educational materials including curriculum plans from Oregon, Maine, and federal agencies. (DK)

  9. Hybrid community energy systems.

    SciTech Connect

    Jody, B. J.; Daniels, E. J.; Karvelas, D. E.; Energy Systems

    2000-01-01

    The availability of efficient, economical, and reliable energy supplies can help attract industry and commercial businesses to a municipality or a region. Efficient use of energy can also improve the air quality and reduce pollution. Therefore, municipalities should explore and encourage the development and implementation of efficient energy systems. Integrated hybrid energy systems can be designed to meet the total energy requirements of large and small communities. These systems can yield significant energy and cost savings when compared with independent systems serving individual units or when compared with the conventional practice of buying power from a utility and producing thermal energy on-site. To maximize energy and cost savings, the design engineer should look beyond the conventional when designing such systems.

  10. GeoEnergy technology

    SciTech Connect

    1980-12-31

    The goal of the GeoEnergy Technology Program is to improve the understanding and efficiency of energy extraction and conversion from geologic resources, hence maintaining domestic production capability of fossil energy resources and expanding the usage of geothermal energy. The GeoEnergy Technology Program conducts projects for the Department of Energy in four resource areas--coal, oil and gas, synthetic fuels and geothermal energy. These projects, which are conducted collaboratively with private industry and DOE`s Energy Technology Centers, draw heavily on expertise derived from the nuclear weapons engineering capabilities of Sandia. The primary technologies utilized in the program are instrumentation development and application, geotechnical engineering, drilling and well completions, and chemical and physical process research. Studies in all four resource areas are described.

  11. An annotated energy bibliography

    NASA Technical Reports Server (NTRS)

    Blow, S. J.

    1979-01-01

    Comprehensive annotated compilation of books, journals, periodicals, and reports on energy and energy related topics, contains approximately 10,0000 tehcnical and nontechnical references from bibliographic and other sources dated January 1975 through May 1977.

  12. Energy information directory 1998

    SciTech Connect

    1998-11-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the general public. The two principal functions related to this task are: (1) operating a general access telephone line, and (2) responding to energy-related correspondence addressed to the Energy Information Administration (EIA). The Energy Information Directory was developed to assist the NEIC staff, as well as other Department of Energy (DOE) staff, in directing inquiries to the proper offices within DOE, other Federal agencies, or energy-related trade associations. The Directory lists most Government offices and trade associations that are involved in energy matters.

  13. Energy information directory 1994

    SciTech Connect

    Not Available

    1994-03-28

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the general public. The two principal functions related to this task are (1) operating a general access telephone line, and (2) responding to energy-related correspondence addressed to the Energy Information Administration (EIA). The Energy Information Directory was developed to assist the NEIC staff, as well as other Department of Energy (DOE) staff, in directing inquiries to the proper offices within DOE, other Federal agencies, or energy-related trade associations. The Directory is a list of most Government offices and trade associations that are involved in energy matters. It does not include those DOE offices which do not deal with the public or public information.

  14. Industrial Energy Conservation Technology

    SciTech Connect

    Not Available

    1980-01-01

    A separate abstract was prepared for each of the 55 papers presented in this volume, all of which will appear in Energy Research Abstracts (ERA); 18 were selected for Energy Abstracts for Policy Analysis (EAPA). (MCW)

  15. Annual Energy Review 1999

    SciTech Connect

    Seiferlein, Katherine E.

    2000-07-01

    A generation ago the Ford Foundation convened a group of experts to explore and assess the Nation’s energy future, and published their conclusions in A Time To Choose: America’s Energy Future (Cambridge, MA: Ballinger, 1974). The Energy Policy Project developed scenarios of U.S. potential energy use in 1985 and 2000. Now, with 1985 well behind us and 2000 nearly on the record books, it may be of interest to take a look back to see what actually happened and consider what it means for our future. The study group sketched three primary scenarios with differing assumptions about the growth of energy use. The Historical Growth scenario assumed that U.S. energy consumption would continue to expand by 3.4 percent per year, the average rate from 1950 to 1970. This scenario assumed no intentional efforts to change the pattern of consumption, only efforts to encourage development of our energy supply. The Technical Fix scenario anticipated a “conscious national effort to use energy more efficiently through engineering know-how." The Zero Energy Growth scenario, while not clamping down on the economy or calling for austerity, incorporated the Technical Fix efficiencies plus additional efficiencies. This third path anticipated that economic growth would depend less on energy-intensive industries and more on those that require less energy, i.e., the service sector. In 2000, total energy consumption was projected to be 187 quadrillion British thermal units (Btu) in the Historical Growth case, 124 quadrillion Btu in the Technical Fix case, and 100 quadrillion Btu in the Zero Energy Growth case. The Annual Energy Review 1999 reports a preliminary total consumption for 1999 of 97 quadrillion Btu (see Table 1.1), and the Energy Information Administration’s Short-Term Energy Outlook (April 2000) forecasts total energy consumption of 98 quadrillion Btu in 2000. What energy consumption path did the United States actually travel to get from 1974, when the scenarios were drawn

  16. Energy Education Incentives: Evaluating the Impact of Consumer Energy Kits

    ERIC Educational Resources Information Center

    Kirby, Sarah D.; Guin, Autumn; Langham, Laura

    2015-01-01

    Measuring the energy and environmental impact of residential energy education efforts is difficult. The E-Conservation residential energy management program uses consumer energy kits to document the impact of energy-efficient improvements. The consumer energy kit provides an incentive for individuals attending energy education workshop, helps…

  17. Energy information sheets

    SciTech Connect

    1995-07-01

    The National Energy Information Center (NEIC), as part of its mission, provides energy information and referral assistance to Federal, State, and local governments, the academic community, business and industrial organizations, and the public. The Energy Information Sheets was developed to provide general information on various aspects of fuel production, prices, consumption, and capability. Additional information on related subject matter can be found in other Energy Information Administration (EIA) publications as referenced at the end of each sheet.

  18. Learning about saving energy

    SciTech Connect

    1995-02-01

    This fact sheet for use in primary and junior high school classes describes what energy is, how people use energy, and how energy can be conserved. This last section lists ways to save energy in heating and cooling, electric appliances, automobiles, and in manufacturing. A list of activities are suggested and resources for further information, both groups and books, are listed. A glossary is also included.

  19. Annual Energy Outlook

    EIA Publications

    2016-01-01

    Projections in the Annual Energy Outlook 2016 (AEO2016) focus on the factors expected to shape U.S. energy markets through 2040. The projections provide a basis for examination and discussion of energy market trends and serve as a starting point for analysis of potential changes in U.S. energy policies, rules, and regulations, as well as the potential role of advanced technologies.

  20. Three Forms of Energy

    NASA Astrophysics Data System (ADS)

    Pétursson, Sigthór.

    2003-07-01

    The paper, which is intended for students and teachers of general and physical chemistry, presents questions relating to thermal, mechanical, and gas expansion processes and works out the energy involved. The examples illustrate the physical meaning of the SI unit for energy, the joule, and draws attention to the comparison between heat and mechanical energy. The energy expenditure involved in our basic bodily functions versus moderate activity is also discussed.

  1. Dark energy crisis

    NASA Astrophysics Data System (ADS)

    Gu, Je-An

    2010-11-01

    In cosmology we are facing the dark energy crisis: How can we survive huge vacuum energy, meanwhile living with tiny dark energy? For the solution to this crisis, we raise several clues and hints, in particular, supersymmetry and the double hierarchy, Mp-MSM-MDE (Planck-Standard Model-dark energy scales). These two clues naturally lead to a solution with a supersymmetry-breaking brane-world. The train of thought from the clues to the solution is elucidated.

  2. National hydrogen energy roadmap

    SciTech Connect

    None, None

    2002-11-01

    This report was unveiled by Energy Secretary Spencer Abraham in November 2002 and provides a blueprint for the coordinated, long-term, public and private efforts required for hydrogen energy development. Based on the results of the government-industry National Hydrogen Energy Roadmap Workshop, held in Washington, DC on April 2-3, 2002, it displays the development of a roadmap for America's clean energy future and outlines the key barriers and needs to achieve the hydrogen vision goals defined in

  3. Solar energy collection system

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K. (Inventor)

    1977-01-01

    An improved solar energy collection system, having enhanced energy collection and conversion capabilities, is delineated. The system is characterized by a plurality of receivers suspended above a heliostat field comprising a multiplicity of reflector surfaces, each being adapted to direct a concentrated beam of solar energy to illuminate a target surface for a given receiver. A magnitude of efficiency, suitable for effectively competing with systems employed in collecting and converting energy extracted from fossil fuels, is indicated.

  4. Energy in history

    SciTech Connect

    Purs, J.

    1984-01-01

    This book presents the papers given at a symposium on the development of energy technologies in Czechoslovakia during the Industrial Revolution. Topics considered at the symposium included steam drive in the epoch of the Industrial Revolution, the energy crisis in the milling industry of late feudalism, the energy base of the food industry during the industrial and scientific revolution, power engineering in agriculture, and new energy in the transportation sector during the automobile revolution.

  5. International energy outlook 1992

    NASA Astrophysics Data System (ADS)

    1992-04-01

    The report presents the current Energy Information Administration (EIA) assessment of the long-term outlook for international energy markets. The report is provided, as are other EIA reports, as a statistical service for use by managers and international energy analysts and not as a government energy plan. Current U.S. Government policies and foreign government policies are assumed to hold over the projection interval, which extends to the year 2010.

  6. Energy storage apparatus

    NASA Technical Reports Server (NTRS)

    Studer, P. A.; Evans, H. E. (Inventor)

    1978-01-01

    A high efficiency, flywheel type energy storage device which comprises an electronically commutated d.c. motor/generator unit having a massive flywheel rotor magnetically suspended around a ring shaped stator is presented. During periods of low energy demand, the storage devices were operated as a motor, and the flywheel motor was brought up to operating speed. Energy was drawn from the device functioning as a generator as the flywheel rotor rotated during high energy demand periods.

  7. Tips for Energy Savers.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC.

    According to 1986 U.S. Department of Energy data, 48% of our residential energy is used to heat and cool our homes, 16% goes for heating water, 12% is used to refrigerators and freezers, and the remaining 24% goes into lighting, cooking, and running appliances. This booklet contains tips for saving energy, including sections on: (1) draft-proof…

  8. Energy monitoring in gins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Energy costs are the second largest source of variable costs for cotton gins, accounting for 27% of variable costs. Energy use has typically not been a major consideration in gin design, and previous studies of energy use have utilized instantaneous readings or aggregated season-long values. In this...

  9. Foundry energy conservation workbook

    SciTech Connect

    1990-10-01

    This report discusses methods for promoting energy conservation in foundries. Use of electric power, natural gas, and coke are evaluated. Waste heat recovery systems are considered. Energy consumption in the specific processes of electric melting, natural gas melting, heat treatments, ladle melting, and coke fuel melting is described. An example energy analysis is included. (GHH)

  10. Foundry energy conservation workbook

    SciTech Connect

    Not Available

    1990-12-31

    This report discusses methods for promoting energy conservation in foundries. Use of electric power, natural gas, and coke are evaluated. Waste heat recovery systems are considered. Energy consumption in the specific processes of electric melting, natural gas melting, heat treatments, ladle melting, and coke fuel melting is described. An example energy analysis is included. (GHH)

  11. The Energy Primer.

    ERIC Educational Resources Information Center

    Tennessee Valley Authority, Chattanooga. Div. of Power Utilization.

    This publication is an information source on energy for teachers. The information in this publication is factual, and designed for courses of study about energy. This book has been divided into separate energy-related sections. Each section ends with a list of student participation discussion activities. The sections present facts about: (1)…

  12. School District Energy Manual.

    ERIC Educational Resources Information Center

    Association of School Business Officials International, Reston, VA.

    This manual serves as an energy conservation reference and management guide for school districts. The School District Energy Program (SDEP) is designed to provide information and/or assistance to school administrators planning to implement a comprehensive energy management program. The manual consists of 15 parts. Part 1 describes the SDEP; Parts…

  13. A Solar Energy Bibliography.

    ERIC Educational Resources Information Center

    Guthrie, David L.; Riley, Robert A.

    This document contains 5,000 references to literature through 1976 dealing with various aspects of solar energy. Categories are established according to area of solar research. These categories include: (1) overview; (2) measurement; (3) low-range solar energy collection (below 120 degrees C); (4) intermediate-range solar energy collection (120…

  14. World Energy Strategies

    ERIC Educational Resources Information Center

    Lovins, Amory B.

    1974-01-01

    Examines possible energy options and outlines assessments and conclusions influencing recent top level energy thinking and planning. Indicates that no nation on earth appears to have either a coherent long-range energy strategy or the institutions needed to devise one. (JR)

  15. Energy Drinks. Prevention Update

    ERIC Educational Resources Information Center

    Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2010

    2010-01-01

    High-caffeine soft drinks have existed in the United States since at least the 1980s beginning with Jolt Cola. Energy drinks, which have caffeine as their primary "energy" component, began being marketed as a separate beverage category in the United States in 1997 with the introduction of the Austrian import Red Bull. Energy drink consumption and…

  16. Annual Energy Review 2002

    SciTech Connect

    Seiferlein, Katherine E.

    2003-10-01

    The Annual Energy Review (AER) presents the Energy Information Administration’s historical energy statistics. For many series, statistics are given for every year from 1949 through 2002. The statistics, expressed in either physical units or British thermal units, cover all major energy activities, including consumption, production, trade, stocks, and prices, for all major energy commodities, including fossil fuels, electricity, and renewable energy sources. Publication of this report is required under Public Law 95–91 (Department of Energy Organization Act), Section 205(c), and is in keeping with responsibilities given to the Energy Information Administration (EIA) under Section 205(a)(2), which states: “The Administrator shall be responsible for carrying out a central, comprehensive, and unified energy data and information program which will collect, evaluate, assemble, analyze, and disseminate data and information....” The AER is intended for use by Members of Congress, Federal and State agencies, energy analysts, and the general public. EIA welcomes suggestions from readers regarding data series in the AER and in other EIA publications. Related Publication: Readers of the AER may also be interested in EIA’s Monthly Energy Review, which presents monthly updates of many of the data in the AER. Contact our National Energy Information Center for more information.

  17. Energy Sources and Development.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with energy sources and development. Its objective is for the student to be able to discuss energy sources and development related to the historical perspective, biological development, current aspects, and future expectations…

  18. Plugging into Energy Savings.

    ERIC Educational Resources Information Center

    Harrigan, Merrilee

    1999-01-01

    The nonprofit Alliance to Save Energy has been helping schools reduce energy consumption through a combination of retrofits, classroom instruction, and behavior. Lists eight small steps to big energy savings, among them: involve the whole school, stop leaks, turn off computers, and recycle. (MLF)

  19. Solar Energy Development Progresses

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1975

    1975-01-01

    Discusses an engineering conference at which participants agreed that solar energy is a feasible energy source, although costs of such technology are presently very high. Also describes recent developments in solar energy research, and estimates the costs of this technology. (MLH)

  20. Solar Energy Usage.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with solar energy use. Its objective is for the student to be able to discuss the broad aspects of solar energy use and to explain the general operation of solar systems. Some topics covered are availability and economics of solar…

  1. Minnesota and Energy.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Natural Resources, St. Paul. Environmental Education Board.

    Eight energy education activities are provided. Each activity includes an overview, a brief summary, lists of objectives and materials needed, teacher's notes, and student materials. The activities focus on: (1) using social studies skills to understand Minnesota energy data and to clarify and understand some Minnesota energy issues; (2) giving…

  2. Energy Systems Laboratory Groundbreaking

    SciTech Connect

    Hill, David; Otter, C.L.; Simpson, Mike; Rogers, J.W.

    2011-01-01

    INL recently broke ground for a research facility that will house research programs for bioenergy, advanced battery systems, and new hybrid energy systems that integrate renewable, fossil and nuclear energy sources. Here's video from the groundbreaking ceremony for INL's new Energy Systems Laboratory. You can learn more about CAES research at http://www.facebook.com/idahonationallaboratory.

  3. Energy for Education

    ERIC Educational Resources Information Center

    Cook, Emma

    2011-01-01

    Increased energy efficiency and reduced reliance on fossil fuels are both essential if people are to have any chance of avoiding escalating energy prices and the grim reality of catastrophic climate change. By increasing the diversity of energy sources people can also achieve increased security, reducing their dependence on imports. As…

  4. Solar Energy and You.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…

  5. Idaho's Energy Options

    SciTech Connect

    Robert M. Neilson

    2006-03-01

    This report, developed by the Idaho National Laboratory, is provided as an introduction to and an update of the status of technologies for the generation and use of energy. Its purpose is to provide information useful for identifying and evaluating Idaho’s energy options, and for developing and implementing Idaho’s energy direction and policies.

  6. Energy: An Overview.

    ERIC Educational Resources Information Center

    Qayoumi, Mohammad H.

    2003-01-01

    Reviews transformations in the field of energy over the last 30 years, including the 1970s energy crisis and the legislative response, the abandonment of nuclear energy, growing dependence on natural gas, growing dependence on electricity rather than oil, and superconducting technologies. (EV)

  7. Energy Matters - Spring 2002

    SciTech Connect

    2002-03-01

    Quarterly newsletter from DOE's Industrial Technologies Program to promote the use of energy-efficient industrial systems. The focus of the Spring 2002 Issue of Energy Matters focuses on premium energy efficiency systems, with articles on new gas technologies, steam efficiency, the Augusta Newsprint Showcase, and more.

  8. Energy Systems Design

    NASA Technical Reports Server (NTRS)

    1986-01-01

    PRESTO, a COSMIC program, handles energy system specifications and predicts design efficiency of cogeneration systems. These systems allow a company to use excess energy produced to generate electricity. PRESTO is utilized by the Energy Systems Division of Thermo Electron Corporation in the custom design of cogeneration systems.

  9. Energy efficient building design

    SciTech Connect

    Not Available

    1992-03-01

    The fundamental concepts of the building design process, energy codes and standards, and energy budgets are introduced. These tools were combined into Energy Design Guidelines and design contract requirements. The Guidelines were repackaged for a national audience and a videotape for selling the concept to government executives. An effort to test transfer of the Guidelines to outside agencies is described.

  10. Strategies for Energy Use.

    ERIC Educational Resources Information Center

    Gibbons, John H.; And Others

    1989-01-01

    Discusses the efficient use of energy. Compares reserves and pollutants generated by natural gas, oil, and coal. Points out some alternative energy sources and ways for improving energy efficiency in buildings, industrial processes, and transportation. Describes some problems in developing and developed countries. (YP)

  11. The Global Energy Budget.

    ERIC Educational Resources Information Center

    Jax, Daniel W.

    1992-01-01

    Presents a lesson plan about greenhouse effect and global warming. Includes diagrams and graphs from which students are asked to make inferences. Provides background information about how energy enters and leaves the earth system, the energy budget, consequences of obstructing the energy balance, and the greenhouse effect. (three references) (MCO)

  12. Renewable Energy Technology

    ERIC Educational Resources Information Center

    Daugherty, Michael K.; Carter, Vinson R.

    2010-01-01

    In many ways the field of renewable energy technology is being introduced to a society that has little knowledge or background with anything beyond traditional exhaustible forms of energy and power. Dotson (2009) noted that the real challenge is to inform and educate the citizenry of the renewable energy potential through the development of…

  13. Energy and National Security

    ERIC Educational Resources Information Center

    Abelson, Philip H.

    1973-01-01

    Discussed in this editorial is the need for a broad and detailed government policy on energy use. Oil companies can not be given complete responsibility to demonstrate usage of different energy sources. The government should construct plants because energy is connected with national security. (PS)

  14. Renewable Energy in Alaska

    SciTech Connect

    Not Available

    2013-03-01

    This report examines the opportunities, challenges, and costs associated with renewable energy implementation in Alaska and provides strategies that position Alaska's accumulating knowledge in renewable energy development for export to the rapidly growing energy/electric markets of the developing world.

  15. Energy and Change

    ERIC Educational Resources Information Center

    Hecht, Eugene

    2007-01-01

    When Feynman wrote, "It is important to realize that in physics today, we have no knowledge of what energy is," he was recognizing that although we have expressions for various forms of energy from kinetic to elastic, we seem to have no idea of what the all-encompassing notion of "energy" "is": This paper addresses that issue offering a definition…

  16. Geothermal energy in Nevada

    SciTech Connect

    Not Available

    1980-01-01

    The nature of goethermal resources in Nevada and resource applications are discussed. The social and economic advantages of utilizing geothermal energy are outlined. Federal and State programs established to foster the development of geothermal energy are discussed. The names, addresses, and phone numbers of various organizations actively involved in research, regulation, and the development of geothermal energy are included. (MHR)

  17. Chapter 3: Energy Security

    SciTech Connect

    Foust, Thomas D.; Arent, Doug; de Carvalho Macedo, Isaias; Goldemberg, Jose; Hoysala, Chanakya; Filho, Rubens Maciel; Nigro, Francisco E. B.; Richard, Tom L.; Saddler, Jack; Samseth, Jon; Somerville, Chris R.

    2015-04-01

    This chapter considers the energy security implications and impacts of bioenergy. We provide an assessment to answer the following questions: What are the implications for bioenergy and energy security within the broader policy environment that includes food and water security, development, economic productivity, and multiple foreign policy aspects? What are the conditions under which bioenergy contributes positively to energy security?

  18. Energy Systems Laboratory Groundbreaking

    ScienceCinema

    Hill, David; Otter, C.L.; Simpson, Mike; Rogers, J.W.;

    2013-05-28

    INL recently broke ground for a research facility that will house research programs for bioenergy, advanced battery systems, and new hybrid energy systems that integrate renewable, fossil and nuclear energy sources. Here's video from the groundbreaking ceremony for INL's new Energy Systems Laboratory. You can learn more about CAES research at http://www.facebook.com/idahonationallaboratory.

  19. Our Energy Options.

    ERIC Educational Resources Information Center

    Meyers, Paul A.; Witt, Frank C.

    Presented is an analysis of alternatives available to the United States in dealing with energy problems. Options explained and evaluated include coal, solar, hydroelectric, nuclear, geothermal, wind, biomass, and energy conservation. The booklet is part of Project APEC (America's Possible Energy Choices), a nationally validated Title IVc project…

  20. Energy-Water Nexus

    SciTech Connect

    Horak, W.

    2010-07-26

    Conclusions of this presentation are: (1) energy and water are interconnected; (2) new energy sources will place increased demands on water supplies; (3) existing energy sources will be subjected to increasing restrictions on their water use; and (4) integrated decision support tools will need to be developed to help policy makers decide which policies and advanced technologies can address these issues.