Momentum and energy relaxation of warm carriers in semiconductors

Non-linear microwave optics of semiconductors is influenced by two relaxation times τ _m and τ_ɛ which determine energy and momentum relaxation. In the range of warm carriers τ_ɛ is assumed to be not dependent and τ _m linearly dependent on energy. The simple model of band structure of semiconductors and a monoenergetic energy distribution of carriers are assumed. The calculation yields the frequency dependence of the nonlinearity coefficient β as observed by Seeger with Morgan's experimental arrangement (parallel d.c. and a.c. electric fields) also at high frequencies and low temperatures. Furthermore, the h.f. behaviour of frequency multiplication and harmonic mixing are given.