Numerical simulation of low-field thermally stimulated conductivity in a-Si:H

Abstract A numerical simulation of the thermally stimulated conductivity (TSC) in hydrogenated amorphous silicon (a-Si:H) is presented as a function of temperature. All the possible thermal emission, trapping and recombination transitions of free carriers between gap and extended states are considered. The standard distribution of localized states in a-Si:H is used. The rate equations of free and trapped carriers are set up following the Shockley–Read–Hall statistics for both electrons and holes. By solving the complete set of non-linear differential equations the TSC response is calculated without further assumption. The calculation is valid for the smaller electric field approximation and for temperatures high enough to neglect the hopping conduction. For a typical set of microscopic parameters, the calculated TSC curve has two prevalent peaks. The general shape of the TSC and the origin of each peak is given by using the quasi-Fermi level concept and the respective localized charge densities variations.