Nonactivation nature of conductivity in disordered materials

Abstract

The results of investigation of temperature dependence of conductivity in polycrystalline PbS films are presented. The temperature dependence of conductivity, σ( T) in the temperature range from 80 to 350 K is shown to be mainly determined by the temperature dependence of mobility, μ( T), while the concentration of charge carriers is weakly dependent on the temperature. It has been observed, that σ( T) and μ( T) are well rectified in the coordinates ln σ( T) ∼- T/ T 0 ( T 0 is a certain parameter), which correspond to the inverse Arrhenius law, and it is shown that the temperature dependence of mobility μ( T) obeys the same law. The model based on the concepts of strong spatial fluctuations of parameters of the materials and on conclusions of the percolation theory has been suggested to explain the temperature dependence σ( T).