Ultrafast recombination and trapping in amorphous silicon
Contributors: A. Esser, K. Seibert, H. Kurz, G.N. Parsons, C. Wang, B.N. Davidson, G. Lucovsky, and Robert J. Nemanich
ABSTRACT
We have studied time-resolved reflectivity changes induced by femtosecond laser pulses in a-Si and a-Si:H thin-films. By varying pump-power, we have identified a non-radiative recombination process which controls the free-carrier density, N, on a picosecond time scale for N>5 ×1018cm−3 in a-Si:H and >5×1019 cm−3 in a-Si. At lower carrier densities, transients are controlled by trapping of free-carriers.