engleski

Light induced defects in amorhous silicon thin films

The effect of light soakink on a a-Si:H films is well known as Staebler-Wronski effect, though its complete mechanism is not clear yet. We have studied the effect of light soaking with UV, white and sub-gap light on intrinsic a-Si:H films, as well as the effect of thermal annealing in the dark. It is shown that the light soaking of the films in the air did not affect the hydrogen concentrationfrom Si-H bonds and at the same time oxidation of the films is observed. It means that oxygen incorporation was due to broken backbonds to Si-H which are very likely weak bonds. Moreover it is found that while subgap irradiation did not produce oxidation white and UV light did, while UV light caused even minor Si-H bonds breaking. Vacuum annealing at 100 C in the dark on the other hand caused hydrogen redistribution enhancing thus the Si-H bond concentrationand recovering the broken bonds.

ight induced defects; amorphous silicon; thin films

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