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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title (down) Direct measurements of energy relaxation time of electrons in AlGaAs/GaAs heterostructures under quasi-equilibrium conditions Type Journal Article
Year 1996 Publication Surface Science Abbreviated Journal Surface Science
Volume 361-362 Issue Pages 569-573
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract For the first time, results are presented of a direct measurement of the energy relaxation time τε of 2D electrons in an AlGaAs/GaAs heterojunction at T = 1 and 5–20 K. A weak temperature dependence of τε for the T > 4K range and a linear temperature dependence of the reciprocal of τε for T < 4K have been observed. The linear dependence τε−1 ≈ T in the Bloch-Gruneisen regime is direct evidence of the predominance of the piezo-electric mechanism of electron-phonon interaction in non-elastic electron scattering processes. The values of τε in this regime are in very good agreement with the results of the Karpus theory. At higher temperatures, where the deformation-potential scattering becomes noticeable, a substantial disagreement between the experimental data and the theoretical results is observed.
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0039-6028 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1609
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Author Karasik, B. S.; Il'in, K. S.; Pechen, E. V.; Krasnosvobodtsev, S. I.
Title (down) Diffusion cooling mechanism in a hot-electron NbC microbolometer mixer Type Journal Article
Year 1996 Publication Applied Physics Letters Abbreviated Journal Appl. Phys. Lett.
Volume 68 Issue 16 Pages 2285-2287
Keywords HEB mixer, diffusion cooling channel, diffusion channel
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ISSN 0003-6951 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 262
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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title (down) Determination of the limiting mobility of a two-dimensional electron gas in AlxGa1-xAs/GaAs heterostructures and direct measurement of the energy relaxation time Type Journal Article
Year 1996 Publication Phys. Rev. B Condens. Matter. Abbreviated Journal Phys. Rev. B Condens. Matter.
Volume 53 Issue 12 Pages R7592-R7595
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829 ISBN Medium
Area Expedition Conference
Notes PMID:9982274 Approved no
Call Number Serial 1612
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Author Tong, C. Y. E.; Blundell, R.; Paine, S.; Papa, D. C.; Kawamura, J.; Stern, J.; LeDuc, H. G.
Title (down) Design and characterization of a 250-350 GHz fixed-tuned superconductor-insulator-insulator receiver Type Journal Article
Year 1996 Publication IEEE Trans. Microw. Theory Techn. Abbreviated Journal
Volume 44 Issue 9 Pages 1548-1556
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Notes Approved no
Call Number Serial 273
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Author Gousev, Yu. P.; Semenov, A. D.; Pechen, E. V.; Varlashkin, A. V.; Nebosis, R. S.; Renk K. F
Title (down) Coupling of terahertz radiation to a high-Т(с) superconducting hot electron bolometer mixer Type Journal Article
Year 1996 Publication Abbreviated Journal Appl. Phys. Lett.,
Volume 69 Issue Pages 691-693
Keywords
Abstract We report on efficient coupling of THz radiation to a high-T(c) superconducting hot electron bolometer that is suitable for heterodyne detection. Our quasioptical system consisted of a planar self-complementary spiral antenna on a dielectric substrate clamped to an extended hyperhemispherical lens. The antenna was integrated into a co-planar line for broadband intermediate frequency matching. Measurements in the homodyne regime at a frequency of 2.5 THz showed a radiation pattern with a beam width of 1° and a coupling efficiency of 0.1. We measured, at an intermediate frequency of 1.5 GHz, an output noise temperature of'160 K and estimated for the device, operated in the heterodyne regime, a system noise temperature of 30 000 K. We also discuss possibilities of significant improvement of the sensitivity.
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Notes Approved no
Call Number RPLAB @ atomics90 @ Serial 958
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