| Records |
| Author |
Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Gol’tsman, G. N.; Gershenzon, E. M.; Ingvesson, K. S. |
| Title |
Direct measurements of energy relaxation times on an AlGaAs/GaAs heterointerface in the range 4.2–50 K |
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Journal Article |
| Year |
1996 |
Publication |
JETP Lett. |
Abbreviated Journal |
JETP Lett. |
| Volume |
64 |
Issue |
5 |
Pages |
404-409 |
| Keywords |
2DEG, AlGaAs/GaAs heterostructures |
| Abstract |
The temperature dependence of the energy relaxation time τe (T) of a two-dimensional electron gas at an AlGaAs/GaAs heterointerface is measured under quasiequilibrium conditions in the region of the transition from scattering by acoustic phonons to scattering with the participation of optical phonons. The temperature interval of constant τe, where scattering by the deformation potential predominates, is determined. In the preceding, low-temperature region, where piezoacoustic and deformation-potential-induced scattering processes coexist, τ e decreases slowly with increasing temperature. Optical phonons start to participate in the scattering processes at T∼25 K (the characteristic phonon lifetime was equal to τLOτ4.5 ps). The energy losses calculated from the τe data in a model with an effective nonequilibrium electron temperature agree with the published data obtained under strong heating conditions. |
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0021-3640 |
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http://jetpletters.ru/ps/981/article_14955.shtml (“Прямые измерения времен энергетической релаксации на гетерогранице AlGaAs/GaAs в диапазоне 4.2 – 50 К”) |
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1608 |
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| Author |
Smirnov, K. V.; Ptitsina, N. G.; Vakhtomin, Y. B.; Verevkin, A. A.; Gol’tsman, G. N.; Gershenzon, E. M. |
| Title |
Energy relaxation of two-dimensional electrons in the quantum Hall effect regime |
Type |
Journal Article |
| Year |
2000 |
Publication |
JETP Lett. |
Abbreviated Journal |
JETP Lett. |
| Volume |
71 |
Issue |
1 |
Pages |
31-34 |
| Keywords |
2DEG, GaAs/AlGaAs heterostructures |
| Abstract |
The mm-wave spectroscopy with high temporal resolution is used to measure the energy relaxation times τe of 2D electrons in GaAs/AlGaAs heterostructures in magnetic fields B=0–4 T under quasi-equilibrium conditions at T=4.2 K. With increasing B, a considerable increase in τe from 0.9 to 25 ns is observed. For high B and low values of the filling factor ν, the energy relaxation rate τ −1e oscillates. The depth of these oscillations and the positions of maxima depend on the filling factor ν. For ν>5, the relaxation rate τ −1e is maximum when the Fermi level lies in the region of the localized states between the Landau levels. For lower values of ν, the relaxation rate is maximum at half-integer values of τ −1e when the Fermi level is coincident with the Landau level. The characteristic features of the dependence τ −1e (B) are explained by different contributions of the intralevel and interlevel electron-phonon transitions to the process of the energy relaxation of 2D electrons. |
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0021-3640 |
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http://jetpletters.ru/ps/899/article_13838.shtml (“Энергетическая релаксация двумерных электронов в области квантового эффекта Холла”) |
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1559 |
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Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol’tsman, G. N.; Verevkin, A. A.; Toropov, A. I. |
| Title |
Frequency bandwidth and conversion loss of a semiconductor heterodyne receiver with phonon cooling of two-dimensional electrons |
Type |
Journal Article |
| Year |
2010 |
Publication |
Semicond. |
Abbreviated Journal |
Semicond. |
| Volume |
44 |
Issue |
11 |
Pages |
1427-1429 |
| Keywords |
2DEG, AlGaAs/GaAs heterostructures mixers |
| Abstract |
The temperature and concentration dependences of the frequency bandwidth of terahertz heterodyne AlGaAs/GaAs detectors based on hot electron phenomena with phonon cooling of two-dimensional electrons have been measured by submillimeter spectroscopy with a high time resolution. At a temperature of 4.2 K, the frequency bandwidth at a level of 3 dB (f 3 dB) is varied from 150 to 250 MHz with a change in the concentration n s according to the power law f 3dB ∝ n −0.5 s due to the dominant contribution of piezoelectric phonon scattering. The minimum conversion loss of the semiconductor heterodyne detector is obtained in structures with a high carrier mobility (μ > 3 × 105 cm2 V−1 s−1 at 4.2 K). |
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1063-7826 |
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Полоса и потери преобразования полупроводникового смесителя с фононным каналом охлаждения двумерных электронов |
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1216 |
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Smirnov, A. V.; Karmantsov, M. S.; Smirnov, K. V.; Vakhtomin, Y. B.; Masterov, D. V.; Tarkhov, M. A.; Pavlov, S. A.; Parafin, A. E. |
| Title |
Terahertz response of thin-film YBCO bolometers |
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Journal Article |
| Year |
2012 |
Publication |
Tech. Phys. |
Abbreviated Journal |
Tech. Phys. |
| Volume |
57 |
Issue |
12 |
Pages |
1716-1719 |
| Keywords |
YBCO HEB |
| Abstract |
The bolometric response of high-temperature thin-film YBCO superconducting detectors to an electromagnetic radiation with a frequency of 2.5 THz is measured for the first time. The minimum value of the noise-equivalent power of the detectors is 3.5 × 10−9 W/Hz−−−√. The feasibility of further increasing the sensitivity of the detectors is discussed. |
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1063-7842 |
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1817 |
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Gol'tsman, G.; Maslennikov, S.; Finkel, M.; Antipov, S.; Kaurova, N.; Grishina, E.; Polyakov, S.; Vachtomin, Y.; Svechnikov, S.; Smirnov, K.; Voronov, B. |
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Nanostructured ultrathin NbN film as a terahertz hot-electron bolometer mixer |
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Conference Article |
| Year |
2006 |
Publication |
Proc. MRS |
Abbreviated Journal |
Proc. MRS |
| Volume |
935 |
Issue |
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Pages |
210 (1 to 6) |
| Keywords |
NbN HEB mixers |
| Abstract |
Planar spiral antenna coupled and directly lens coupled NbN HEB mixer structures are studied. An additional MgO buffer layer between the superconducting film and Si substrate is introduced. The buffer layer enables us to increase the gain bandwidth of a HEB mixer due to better acoustic transparency. The gain bandwidth is widened as NbN film thickness decreases and amounts to 5.2 GHz. The noise temperature of antenna coupled mixer is 1300 and 3100 K at 2.5 and 3.8 THz respectively. The structure and composition of NbN films is investigated by X-ray diffraction spectroscopy methods. Noise performance degradation at LO frequencies more than 3 THz is due to the use of a planar antenna and signal loss in contacts between the antenna and the sensitive NbN bridge. The mixer is reconfigured for operation at higher frequencies in a manner that receiver’s noise temperature is only 2300 K (3 times of quantum limit) at LO frequency of 30 THz. |
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0272-9172 |
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1440 |
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