Hopping conduction in amorphous solids

Abstract

The hopping conduction process is examined under conditions of high temperatures, high fields and a non-uniform distribution of hopping sites. It is shown that the field dependence of the Mott T ^−¼ law can yield information about the trap density distribution. A new mechanism of conduction, considering the emission of charge carriers from donor centres into traps, is examined and shown to yield a characteristic of ln σ∞T ^−1/7. The electrical properties of amorphous carbon and germanium are examined. It is shown that carbon exhibits a pure hopping process whilst germanium shows the characteristics of donor emission into traps.