6,814 research outputs found
Multijunction cells for concentrators: Technology prospects
Development of high-efficiency multijunction solar cells for concentrator applications is a key step in achieving the goals of the U.S. Department of Energy National Photovoltaics Program. This report summarizes findings of an issue study conducted by the Jet Propulsion Laboratory Photovoltaic Analysis and Integration Center, with the assistance of the Solar Energy Research Institute and Sandia National laboratoies, which surveyed multijunction cell research for concentrators undertaken by federal agencies and by private industry. The team evaluated the potentials of research activities sponsored by DOE and by corporate funding to achieve projected high-efficiency goals and developed summary statements regarding industry expectations. Recommendations are made for the direction of future work to address specific unresolved aspects of multijunction cell technology
Silicon-sheet and thin-film cell and module technology potential: Issue study
The development of high-efficiency low-cost crystalline silicon ribbon and thih-film solar cells for the energy national photovoltaics program was examined. The findings of an issue study conducted are presented. The collected data identified the status of the technology, future research needs, and problems experienced. The potentials of present research activities to meet the Federal/industry long-term technical goal of achieving 15 cents per kilowatt-hour levelized PV energy cost are assessed. Recommendations for future research needs related to crystalline silicon ribbon and thin-film technologies for flat-plate collectors are also included
Pressure, Resistance, and Current Activation of Anisotropic Compressible Hall States
Thermodynamic and electric properties of anisotropic compressible Hall states
at higher Landau levels are studied using a mean field theory on the von
Neumann lattice basis. It is shown that resistances agree with the recent
experiments of anisotropic compressible states and the states have negative
pressure. As implications, the collapse phenomena of the integer quantum Hall
effect are discussed.Comment: 4 pages, 5 figures, to be published in Physica
Indication of Te segregation in laser-irradiated ZnTe observed by in situ coherent-phonon spectroscopy
We irradiate a ZnTe single crystal with 10-fs laser pulses at a repetition
rate of 80 MHz and investigate its resulting gradual modification by means of
coherent-phonon spectroscopy. We observe the emergence of a phonon mode at
about 3.6 THz whose amplitude and lifetime grow monotonously with irradiation
time. The speed of this process depends sensitively on the pump-pulse
duration. Our observations strongly indicate that the emerging phonon mode
arises from a Te phase induced by multiphoton absorption of incident laser
pulses. A potential application of our findings is laser-machining of
microstructures in the bulk of a ZnTe crystal, a highly relevant electrooptic
material
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