Deep-level transient spectroscopy (DLTS) analysis of defect levels in semiconductor alloys

A deep trap in the fundamental gap of a semiconductor has a sharp (delta function) character. In a semiconductor alloy the presence of disorder introduces a distribution of trap activation energies. The authors have undertaken a detailed analytical and numerical exercise to examine the effect of such broadening on the capacitance transient and on deep-level transient spectroscopy (DLTS) analysis of traps. In general the standard DLTS analysis introduces negligible error except in cases of severe broadening where it overestimates the activation energy. They illustrate their analysis by considering both simulated and actual experimental situations.