On the Electron-Lattice Interaction in Non-Polar Semiconductors

Abstract

The two-phonon process in non-polar semiconductors is discussed and the acoustical mode-scattering mobility is derived from this type of electron-lattice interaction. The obtained mobility depends on T-2. This result is combined with the usual one which depends on T-1.5, and it is concluded that the one-phonon process treated in the usual theory is predominant at lower temperature while the two-phonon process is predominant at higher temperature. Then it is shown that the transition of mobility from the one-phonon region to the two-phonon region well accounts for the transition of temperature dependence observed on the lattice scattering mobility in each case of electrons and holes in germanium and silicon. The small deviations of temperature dependence of the observed mobilities from T-2 or T-1.5 seem to be explained with the optical mode-scattering.