Electrically detected transient photocarrier grating method

We present the measurement and analysis of the transient behavior of the photocurrent in amorphous semiconductor thin films in the presence of a photocarrier grating. The photocurrent transients are governed essentially by two processes, recombination and interdiffusion. The general features of the experimental findings can be reproduced analytically under small-signal conditions. In a new method, which we call the electrically detected photocarrier grating method, the response time of photogenerated carriers and the ambipolar diffusion coefficient can be measured simultaneously.