Records |
Author |
Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. |
Title |
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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0163-1829 |
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PMID:9982274 |
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1612 |
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Author |
Fu, K.; Zannoni, R.; Chan, C.; Adams, S. H.; Nicholson, J.; Polizzi, E.; Yngvesson, K. S. |
Title |
Terahertz detection in single wall carbon nanotubes |
Type |
Journal Article |
Year |
2008 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
92 |
Issue |
3 |
Pages |
033105 |
Keywords |
HEB, single wall, carbon nanotube, CNT, SWNT, SWCNT, terahertz detection, THz |
Abstract |
It is reported that terahertz radiation from 0.69 to 2.54 THz has been sensitively detected in a device consisting of bundles of carbon nanotubes containing single wall metallic carbon nanotubes, quasioptically coupled through a lithographically fabricated antenna, and a silicon lens. The measured data are consistent with a bolometric detection process in the metallic tubes and the devices show promise for operation well above 4.2 K. |
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0003-6951 |
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NEP is not shown |
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566 |
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Author |
Rodriguez-Morales, F.; Zannoni, R.; Nicholson, J.; Fischetti, M.; Yngvesson, K. S.; Appenzeller, J. |
Title |
Direct and heterodyne detection of microwaves in a metallic single wall carbon nanotube |
Type |
Journal Article |
Year |
2006 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
89 |
Issue |
8 |
Pages |
083502 |
Keywords |
carbon nanotube, GHz heterodyne detector, direct detector |
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0003-6951 |
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565 |
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Author |
Zhang, W.; Khosropanah, P.; Gao, J. R.; Kollberg, E. L.; Yngvesson, K. S.; Bansal, T.; Barends, R.; Klapwijk, T. M. |
Title |
Quantum noise in a terahertz hot electron bolometer mixer |
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Journal Article |
Year |
2010 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
96 |
Issue |
11 |
Pages |
111113-(1-3) |
Keywords |
HEB mixer, quantum limit, quantum noise, vacuum box, THz, Terahertz |
Abstract |
We have measured the noise temperature of a single, sensitive superconducting NbN hot electron bolometer (HEB) mixer in a frequency range from 1.6 to 5.3 THz, using a setup with all the key components in vacuum. By analyzing the measured receiver noise temperature using a quantum noise (QN) model for HEB mixers, we confirm the effect of QN. The QN is found to be responsible for about half of the receiver noise at the highest frequency in our measurements. The beta-factor (the quantum efficiency of the HEB) obtained experimentally agrees reasonably well with the calculated value. |
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624 |
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