Relaxation of photoinduced sub-bandgap absorption in a-Si:H

Journal ArticleThe decay of photoinduced sub-bandgap absorption (PA) following pulsed excitation was studied in the temperature range 80 - 305K, in a-Si:H samples prepared by glow discharge and sputtering. The decay was interpreted in terms of bimolecular diffusion limited recombination involving dispersive transport of electrons and was used for the determination of the dispersion parameter a. It was found to be a linear function of T in the glow-discharge sample while it was weakly T-dependent in the sputtered sample. In addition, a first measurement of the time evolution of the PA spectrum is reported