Search for: [Abstrakt = "The influence of surface state density NSS and bulk non\-radiative lifetime t on room temperature photoluminescence quantum efficiency YPL 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 YPL\(F \) to a change in magnitude of NSS, especially for high NSS and at low F, whereas SPV is practically insensitive to t contrary to YPL. The simultaneous measurement of YPL 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."]