Vol. 35, Issue 3, pp. 355-361 (2005)

Abstract

The influence of surface state density N_SS and bulk non-radiative lifetime t on room temperature photoluminescence quantum efficiency Y_PL and surface photovoltage (SPV) versus the excitation light intensity F was studied theoretically for GaAs and wurtzite GaN using self-consistent computer simulations. It was demonstrated that SPV(F ) dependences are more sensitive than Y_PL(F ) to a change in magnitude of N_SS, especially for high N_SS and at low F, whereas SPV is practically insensitive to t contrary to Y_PL. The simultaneous measurement of Y_PL and SPV versus F, combined with rigorous computer analysis, seems to be a very promising method for contactless characterization of the surface and bulk trap parameters.