Thermally induced metastability and the Meyer-Neldel rule in hydrogenated amorphous silicon

Abstract

A stepwise decrease in the annealing temperature alters the conductivity prefactor sigma ₀ and activation energy E_A of a-Si:H and a linear dependence of ln sigma ₀ on E_A occurs (the Meyer-Neldel rule). It is assumed that temperature-induced changes in the density of states in the mobility gap are responsible for this behaviour. Furthermore, these results are compared with the influence of a stepwise annealing of light-induced defects on temperature-dependent conductivity. The experimental findings are evidence for the existence of a generalised Meyer-Neldel rule in a-Si:H.