Semiconductor Physics, Quantum Electronics & Optoelectronics. 2008. V. 11, N 1. P. 043-049.

High-frequency properties of systems
with drifting electrons and polar optical phonons
S.M. Kukhtaruk

V. Lashkaryov Institute of Semiconductor Physics, 41, prospect Nauky, 03028 Kyiv, Ukraine
E-mail: kukhtaruk@isp.kiev.ua

Abstract. An analysis of interaction between drifting electrons and optical phonons in
semiconductors is presented. Three physical systems are studied: three-dimensional
electron gas (3DEG) in bulk material; two-dimensional electron gas (2DEG) in a
quantum well, and two-dimensional electron gas in a quantum well under a metal
electrode. The Euler and Poisson equations are used for studying the electron subsystem.
Interaction between electrons and polar optical phonons are taken into consideration
using a frequency dependence of the dielectric permittivity. As a result, the dispersion
equations that describe self-consistent collective oscillations of plasmons and optical
phonons are deduced. We found that interaction between electrons and optical phonons
leads to instability of the electron subsystem. The considered physical systems are
capable to be used as a generator or amplifier of the electromagnetic radiation in the 10
THz frequency range. The effect of instability is suppressed if damping of optical
phonons and plasma oscillations is essentially strong.