Photoconductive Decay in Amorphous Silicon Films

The photoconductive current behaviors were measured for amorphous silicon films prepared by plasma decomposition and sputtering. The decays becomes faster for shorter and stronger excitation pulse and the slow components of the decays are independent of them and behave as τ -0.5 . The results can be interpreted using a model in which lifetimes of excess carriers are distributed in wide range. It becomes clear that the distribution function G(τ) is consisted of two main components, fast (ττ 0 ) relaxation processes. In the plasma decomposition sample τ 0 is 1 µisec and in the sputtered sample τ 0 is 0.1 µsec.