Above-band-gap emission in amorphous semiconductors: Localized states versus surface contamination

摘要: The nature of the above-band-gap emission which has been reported by Shah and co-workers in a number amorphous semiconductors is investigated. remarkable features this have attributed to unique properties electronic states these materials. Similar observed other materials, however, where they were ascribed contamination effects. Using Raman phonon spectrum for calibration, study finds intensity from silicon be sensitive surface cleaning procedures. This suggests that may due contamination, unrelated bulk material. A simple model describing optical mixture organic contaminants proposed capable reproducing essential features.