Potential of Hydrogenated Amorphous Silicon-Chalcogen Alloys for Photovoltaic Applications: The Role of Persistent Photoconductivity

The potential improvement in stability of hydrogenated silicon-sulfur alloys (a-SiSx:H) with respect to ordinary hydrogenated amorphous silicon (a-Si:H) has been attributed to the introduction of an additional metastability known as persistent photoconductivity (PPC). In order to examine the PPC process in more detail we examine a series of alloys with large sulfur concentrations (x>0.01).Although these alloys are not useful in photovoltaic devices, the high sulfur concentrations accentuate the PPC effect and allow one to study this effect with little competition from the ordinary Staebler-Wronski effect that dominates the metastable processes that occur in a-Si:H.