Dependence of the anisotropy parameter of drag thermo-emf on the impurity concentration in the n-type germanium and silicon crystals

Abstract

Features of the concentration dependences of the anisotropy parameter of thermo-emf of electron-phonon drag M in germanium and silicon crystals of n-type conductivity were found in a wide range of charge carrier concentrations. Insensitivity of the anisotropy parameter M to the presence of impurities in the germanium crystals up to the concentrations of ∼ 10¹⁵ cm⁻³ was found, whereas in silicon, with increasing the doping level, the monotonic decrease in this parameter was observed. The significantly lower absolute values of the parameter M were obtained for the silicon crystals as compared with the corresponding values of this parameter for the germanium ones. The physical nature of the identified effects was explained.