Evaluation of Mott's Parameters for Hopping Conduction in Amorphous Ge, Si, and Se-Si

Abstract

The temperature dependence of electrical conductivity of rf-sputtered amorphous Ge, Si, and Ge-Si films as functions of annealing temperature and time have been investigated for $350\ensuremath{\gtrsim}T\ensuremath{\gtrsim}77$ K. Annealing shifts the hopping region to lower temperatures. We find that reasonable values of Mott's parameters are obtained only for properly annealed specimens in the true hopping-conduction region.