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Author (down) Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol’tsman, G. N.; Verevkin, A. A.; Toropov, A. I. url  doi
openurl 
  Title Concentration dependence of the intermediate frequency bandwidth of submillimeter heterodyne AlGaAs/GaAs nanostructures Type Journal Article
  Year 2010 Publication Bull. Russ. Acad. Sci. Phys. Abbreviated Journal Bull. Russ. Acad. Sci. Phys.  
  Volume 74 Issue 1 Pages 100-102  
  Keywords 2DEG AlGaAs/GaAs heterostructures, THz heterodyne detectors, IF bandwidth  
  Abstract The concentration dependence of the intermediate frequency bandwidth of heterodyne AlGaAs/GaAs detectors with 2D electron gas is measured using submillimeter spectroscopy with high time resolution at T= 4.2 K. The intermediate frequency bandwidth f3dBfalls from 245 to 145 MHz with increasing concentration of 2D electrons n s = (1.6-6.6) × 10[su11] cm-2. The dependence f3dB ≈ n s – 0.04±is observed in the studied concentration range; this dependence is determined by electron scattering by the deformation potential of acoustic phonons and piezoelectric scattering.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1062-8738 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1217  
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Author (down) Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Goltsman, G. N.; Verevkin, A. A.; Toropov, A. I.; Mauskopf, P. url  doi
openurl 
  Title Concentration dependence of energy relaxation time in AlGaAs/GaAs heterojunctions: direct measurements Type Journal Article
  Year 2011 Publication Semicond. Sci. Technol. Abbreviated Journal Semicond. Sci. Technol.  
  Volume 26 Issue 2 Pages 025013  
  Keywords AlGaAs/GaAs heterojunctions  
  Abstract We present measurements of the energy relaxation time, τε, of electrons in a single heterojunction in a quasi-equilibrium state using microwave time-resolved spectroscopy at 4.2 K. We find the relaxation time has a power-law dependence on the carrier density of the two-dimensional electron gas, τε∝nγs with γ = 0.40 ± 0.02 for values of the carrier density, ns, from 1.6 × 1011 to 6.6 × 1011cm−2. The results are in good agreement with predictions taking into account the scattering of the carriers by both piezoelectric and deformation potential acoustic phonons. We compare these results with indirect measurements of the energy relaxation time from energy loss measurements involving Joule heating of the electron gas.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0268-1242 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1215  
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Author (down) Shaha, Jagdeep; Pinczukb, A.; Gossardb, A. C.; Wiegmannb, W. openurl 
  Title Hot carrier energy loss rates in GaAs quantum wells: large differences between electrons and holes Type Journal Article
  Year 1985 Publication Phys. B+C Abbreviated Journal  
  Volume 134 Issue 1-3 Pages 174-178  
  Keywords 2DEG, GaAs/AlGaAs, heat flow, electron-phonon, hole-phonon, carrier-phonon, interactions  
  Abstract The first direct and separate determination of the hot electron and hot hole energy loss rates to the lattice shows unexpectedly large differences between electrons and holes in GaAs quantum wells. This large difference results from an anomalously low electron energy loss rate, which we attribute to the presence of non-equilibrium optical phonon rather than the effects of reduced dimensionality or dynamic screening. A model calculation of hot phonon effects is presented.  
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  Notes Approved no  
  Call Number Serial 634  
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Author (down) Shah, Nayana; Pekker, David; Goldbart, Paul M. doi  openurl
  Title Inherent stochasticity of superconductor-resistor switching behavior in nanowires Type Journal Article
  Year 2008 Publication Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.  
  Volume 101 Issue Pages 207001(1 to 4)  
  Keywords superconducting nanowires, phase-slip, self-heating effect, temperature profile  
  Abstract We study the stochastic dynamics of superconductive-resistive switching in hysteretic current-biased superconducting nanowires undergoing phase-slip fluctuations. We evaluate the mean switching time using the master-equation formalism, and hence obtain the distribution of switching currents. We find that as the temperature is reduced this distribution initially broadens; only at lower temperatures does it show the narrowing with cooling naively expected for phase slips that are thermally activated. We also find that although several phase-slip events are generally necessary to induce switching, there is an experimentally accessible regime of temperatures and currents for which just one single phase-slip event is sufficient to induce switching, via the local heating it causes.  
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  Notes Approved no  
  Call Number Serial 919  
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Author (down) Shah, Jagdeep; Pinczuk, A.; Gossard, A. C.; Wiegmann, W. openurl 
  Title Energy-loss rates for hot electrons and holes in GaAs quantum wells Type Journal Article
  Year 1985 Publication Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.  
  Volume 54 Issue Pages 2045-2048  
  Keywords 2DEG, GaAs/AlGaAs, heat flow, electron-phonon, hole-phonon, carrier-phonon, interactions  
  Abstract We report the first direct determination of carrier-energy-loss rates in a semiconductor. These measurements provide fundamental insight into carrier-phonon interactions in semiconductors. Unexpectedly large differences are found in the energy-loss rates for electrons and holes in GaAs/AlGaAs quantum wells. This large difference results from an anomalously low electron-energy-loss rate, which we attribute to the presence of nonequilibrium optical phonons rather than the effects of reduced dimensionality or dynamic screening.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 633  
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