Analysis of the steady-state photocarrier grating method for the determination of the density of states in semiconductors

摘要: In this paper we present a complete theoretical analysis of the steady-state photocarrier grating sSSPGd method, starting from generalized equations that describe charge transport and recombination under conditions. The analytical solution these application simplifying assumptions leads to very simple formula relating density states sDOSd at quasi-Fermi level for trapped electrons SSPG signal large periods. By means numerical calculations reproducing experimental curves test our method DOS determination. We examine previous descriptions experiment, illustrating case when measurements are performed different illumination intensities. propose procedure estimate minority-carriers mobility-lifetime product curves, introducing correction commonly applied formula. illustrate usefulness technique determining in gap intrinsic semiconductors, underline its limitations hydrogenated amorphous silicon. an improves accuracy SSPG-DOS reconstruction. Finally, experimentally new by comparing obtained modulated photocurrent on same samples. both methods good agreement.