Evidence for Light-Induced Increase of Si-H Bonds in Undopeda-Si: H

The light-induced change of Si-H bonds in undoped a-Si: H has been investigated by tracing the change of the absorption coefficient related to the Si-H stretching mode, using a specially designed differential method. The results unambiguously show that the Si-H bonds increase with the illumination time, following the same stretched exponential rule as the dangling bonds. The change of the Si-H bonds can be reversed by annealing. These findings bear out a close correlation between the changes of the Si-H bonds and the dangling bonds under illumination.