A chemical bonding model for photo-induced defects in hydrogenated amorphous silicon (a-Si:H): intrinsic and extrinsic reaction pathways

摘要

In device grade a-Si:H photo- or light-induced defect generation is an intrinsic effect for impurity concentrations of oxygen and nitrogen below about 10~19 to 10~20 cm~-3; however,at higher concentrations it increases with incresing impurity content.Charged defect configurations are identified by empirical chemistry and are studied by ab initio calculations.This paper addresses: i) the chemical stability of charged defects, ii) the reaction pathways for defect metastability,and iii) the transition between extrinsic and intrinsic behavior.