On defining the optical gap of an amorphous semiconductor: an empirical calibration for the case of hydrogenated amorphous silicon

Abstract

It is pointed out that there are a number of different means whereby the optical gap of an amorphous semiconductor may be defined. We analyze some hydrogenated amorphous silicon data with respect to a number of these empirical measures for the optical gap. By plotting these gap measures as a function of the breadth of the optical absorption tail, we provide a means of relating these disparate measures of the optical gap.