DEFECTS IN AMORPHOUS Si:H — THE REHYBRIDIZED TWO-SITE (RTS) MODEL

Abstract

A comprehensive model for the metastable defects in amorphous Si:H is developed by adapting a recent theory for several kinds of defects in crystalline semiconductors, particularly the DX center in AlGaAs. This new model accounts in a unified way for all of the major observations of defects induced by light, quenching, doping, or compensation; as well as for their anneal. The stretched-exponential time dependence of defect densities with light exposure or annealing, and saturation of the density are also explained. This model is based on foreign atoms rather than on breaking of Si-Si bonds, and in undoped materials it is suggested that unintentional impurities are the source.