Annealing of Metastable Recombination Centers in Hydrogenated Amorphous Silicon

Abstract

We report results on the annealing behaviors of light- and deposition-induced metastable recombination centers, as measured by steady-state photoconductivity, in undoped hydrogenated amorphous silicon. The relaxation time inferred from the stretched-exponential time law reveals a thermally activated behavior, and the activation energies are nearly identical in both (E_a=1.1eV). This value is much less than that of the light-induced darkconductivity relaxation (E_a=1.7eV) measured simultaneously with photoconductivity. While in the deposition-induced case both activation energies of dark- and photoconductivity relaxation time are identical. These results support that there is more than one kind of defect created by light exposure, and at least, as considering activation energies for annealing defects, the light-induced recombination center differ from other metastable defects.