Phonon mechanism of mobility equilibrium fluctuation and properties of 1/ f-noise

The main mechanisms of the generation of the equilibrium fluctuations of the electron mobility in homogeneous and non-degenerate semiconductors are studied. It is proven that the mobility fluctuations are related to energy fluctuations and are conditioned by random non-elastic scattering and generation–recombination processes. In particular, it is shown that the mobility fluctuations come into existence as a result of random electron–phonon and phonon–phonon scattering processes. The case of acoustic phonon–phonon scattering is considered in detail. The spectral density of the electron lattice mobility fluctuations is calculated on the base of a new phonon mechanism. It is shown that the noise spectrum over a broad frequency range has a 1/ f form. The theoretical results for many samples agree with experimental data.