Topological defects and the Staebler-Wronski effect in hydrogenated amorphous silicon

We propose that the light-induced formation of topological defects may be the origin of the Staebler-Wronski effect in hydrogenated amorphous silicon. Such defect is characterized by a five- and seven-membered ring pair and two dangling bonds, which can trap mobile H to form a 2H metastable complex. This model shows that the photogeneration of the dangling bonds is the result of the topological transformations, whereas the role of the H is to move the photogenerated dangling bonds away from where they were generated. (C) 2005 American Institute of Physics.