Thermal annealing of light-induced defects in hydrogenated amorphous silicon: Evidence for hole-induced annealing

Abstract

Experimental evidence for light-induced annealing of defects in hydrogenated amorphous silicon has recently been reported. The light-induced annealing term has been shown to be proportional to the product of defect density and the carrier density. These results were obtained under illumination and it was not possible to decide which types of carrier, electron or hole were driving the annealing. In the present work the annealing rate of light-induced defects has been studied in the dark at different temperatures. By varying the defect density and the dark conductivity present at the early stage of annealing, we have shown that, at any given temperature, the annealing rate is proportional to the inverse of the dark conductivity, as expected if annealing is driven by holes. The activation energy of the annealing pre-factor is 0·4–0·5 eV, as in the case of light-induced annealing.