Two characteristic photoluminescence states in a-Si:H and its alloys

Photoluminescence (PL) in a-Si:H and its alloys exhibits interesting characteristics related to the metastability of a disordered material. Two lifetime components, which are characterized with respective specific peak lifetimes of about 1 ms and 10 μs are commonly observed in a PL-lifetime distribution throughout the systems, irrespective of their difference in a localized tail-state distribution. With the aid of the modulated IR-absorption measurement that can detect structural instability in the vicinity of the Si–H bond, the characteristics of the two lifetime components are discussed based on the model that the PL corresponding to those lifetime components is caused by a localized PL center associated with some special structural unit.