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

A numerical simulation of the thermally stimulated conductivity (TSC) in hy drogenated amorphous silicon (a-Si:H) is presented as a function of tempera ture. All the possible thermal emission, trapping and recombination transit ions of free carriers between gap and extended states are considered. The s tandard distribution of localized states in a-Si:H is used. The rate equati ons of free and trapped carriers are set up following the Shockley-Read-Hal l statistics for both electrons and holes. By solving the complete set of n on-linear differential equations the TSC response is calculated without fur ther assumption. The calculation is valid for the smaller electric held app roximation and for temperatures high enough to neglect the hopping conducti on. For a typical set of microscopic parameters, the calculated TSC curve h as 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 lo calized charge densities variations. (C) 2000 Elsevier Science B.V. All rig hts reserved.