Hubmann, S. and Gebert, S. and Budkin, G. V. and Bel'kov, V. V. and Ivchenko, E. L. and Dmitriev, A. P. and Baumann, S. and Otteneder, M. and Ziegler, J. and Disterheft, D. and Kozlov, D. A. and Mikhailov, N. N. and Dvoretsky, S. A. and Kvon, Z. D. and Weiss, D. and Ganichev, S. D. (2019) High-frequency impact ionization and nonlinearity of photocurrent induced by intense terahertz radiation in HgTe-based quantum well structures. PHYSICAL REVIEW B, 99 (8): 085312. ISSN 2469-9950, 2469-9969
Full text not available from this repository.Abstract
We report on a strong nonlinear behavior of the photogalvanics and photoconductivity under excitation of HgTe quantum wells (QWs) by intense terahertz (THz) radiation. The increasing radiation intensity causes an inversion of the sign of the photocurrent and transition to its superlinear dependence on the intensity. The photoconductivity also shows a superlinear raise with the intensity. We show that the observed photoresponse nonlinearities are caused by the band-to-band light impact ionization under conditions of a photon energy less than the forbidden gap. The signature of this kind of impact ionization is that the angular radiation frequency omega = 2 pi f is much higher than the reciprocal momentum relaxation time. Thus the impact ionization takes place solely because of collisions in the presence of a high-frequency electric field. The effect has been measured on narrow HgTe/CdTe QWs of 5.7 nm width; the nonlinearity is detected for linearly and circularly polarized THz radiation with different frequencies ranging from f = 0.6 to 1.07 THz and intensities up to hundreds of kW/cm(2). We demonstrate that the probability of the impact ionization is proportional to the exponential function, exp(-E-0(2)/E-2), of the radiation electric field amplitude E and the characteristic field parameter E-0. The effect is observable in a wide temperature range from 4.2 to 90 K, with the characteristic field increasing with rising temperature.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTON-DRAG; SEMICONDUCTOR; LIGHT; ABSORPTION; RESONANCES; INSULATOR; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics Physics > Institute of Experimental and Applied Physics > Professor Ganichev > Group Sergey Ganichev |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Apr 2020 05:43 |
| Last Modified: | 17 Apr 2020 05:43 |
| URI: | https://pred.uni-regensburg.de/id/eprint/27511 |
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