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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 |
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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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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Gol’tsman, G. N.; Verevkin, A. A.; Toropov, A. I. |
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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1062-8738 |
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1217 |
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Shangina, E. L.; Smirnov, K. V.; Morozov, D. V.; Kovalyuk, V. V.; Goltsman, G. N.; Verevkin, A. A.; Toropov, A. I.; Mauskopf, P. |
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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0268-1242 |
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1215 |
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Sergeev, A.; Semenov, A.; Trifonov, V.; Karasik, B.; Gol'tsman, G.; Gershenzon, E. |
Title |
Heat transfer in YBaCuO thin film/sapphire substrate system |
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Journal Article |
Year |
1994 |
Publication |
J. Supercond. |
Abbreviated Journal |
J. Supercond. |
Volume |
7 |
Issue |
2 |
Pages |
341-344 |
Keywords |
YBCO films |
Abstract |
The thermal boundary resistance at the YBaCuO thin film/Al2O3 substrate interface was investigated. The transparency for thermal phonons incident on the interface as well as for phonons moving from the substrate was determined. We have measured a transient voltage response of current-biased films to continuously modulated radiation. The observed knee in the modulation frequency dependence of the response reflects the crossover from the diffusion regime to the contact resistance regime of the heat transfer across the interface. The values of transparency were independently deduced both from the phonon escape time and from the time of phonon return to the film which were identified with peculiarities in the frequency dependence. The results are much more consistent with the acoustic mismatch theory than the diffuse mismatch model. |
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0896-1107 |
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1647 |
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Sergeev, A.; Mitin, V. |
Title |
Electron-phonon interaction in disordered conductors: Static and vibrating scattering potentials |
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Journal Article |
Year |
2000 |
Publication |
Phys. Rev. B. |
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Phys. Rev. B. |
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61 |
Issue |
9 |
Pages |
6041-6047 |
Keywords |
disordered conductors, scattering potential, electron-phonon interaction |
Abstract |
Employing the Keldysh diagram technique, we calculate the electron-phonon energy relaxation rate in a conductor with the vibrating and static δ-correlated random electron-scattering potentials. If the scattering potential is completely dragged by phonons, this model yields the Schmid’s result for the inelastic electron-scattering rate τ−1e−ph. At low temperatures the effective interaction decreases due to disorder, and τ−1e−ph∝T4l (l is the electron mean-free path). In the presense of the static potential, quantum interference of numerous scattering processes drastically changes the effective electron-phonon interaction. In particular, at low temperatures the interaction increases, and τ−1e−ph∝T2/l. Along with an enhancement of the interaction, which is observed in disordered metallic films and semiconducting structures at low temperatures, the suggested model allows us to explain the strong sensitivity of the electron relaxation rate to the microscopic quality of a particular film. |
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0163-1829 |
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307 |
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