An argument for potential fluctuations in amorphous-silicon-based alloys, and their effect on solar celi performance

Abstract

In this paper, we review and compare the properties of glow-discharge a-Si: H alloy with a-Si:H prepared by other techniques as well as with alloys such as hydrogenated amorphous silicon-germanium (a-Si_{1 -x}Ge_x: H) alloys. We point out that there are unique properties associated with high-quality a-Si:H alloys normally prepared by the glow-discharge method, primarily the absence of the 2080 cm⁻¹ infrared peak and the presence of non-dispersive electron transient behaviour. We make an attempt to link this with the presence of long-range potential fluctuations and consider how this may decrease the electron mobility which indirectly decreases the lifetime of holes and hence limits the solar celi performance of ‘inferior’ alloys as a-Si_1-xGe_x:H.