A quantitative characterization of the optical absorption spectrum associated with hydrogenated amorphous silicon

Abstract

We propose a quantitative means of characterizing the optical absorption spectrum associated with an amorphous semiconductor. In particular, for a representative hydrogenated amorphous silicon optical absorption experimental data set, through a series of least-squares linear fits of an exponential function to this experimental data set, taken over a number of optical absorption ranges, we determine how the breadth of the optical absorption tail varies along the optical absorption spectrum of hydrogenated amorphous silicon. We find that the quantitative variations in the breadth of the optical absorption tail that are found provide for a clear delineation between the different regions of the optical absorption spectrum of hydrogenated amorphous silicon. We complete this analysis by theoretically determining the form of the optical absorption spectrum using a recently developed empirical model for the density of states functions corresponding to hydrogenated amorphous silicon, this analysis providing a theoretical basis for the interpretation of our results.