Amplification of optical phonons in semiconductor quantum wells at finite temperatures

It is investigated the generation of terahertz radiation with using the oscillations of crystalline lattices. The numerical simulations are presented of the instability of the optical phonons of THz range in the semiconductor structures with quantum wells under the drift of 2D electron gas. The main obstacle for the realization of this instability is the heating of the electron gas. Therefore the low but finite temperatures are considered T ≤ 77 K, and the electron gas is degenerate. In the numerical simulations the kinetic approach is used. It is shown that the structures on the base on GaAs are preferable to observe this instability.