NON-GAUSSIAN TRANSPORT MEASUREMENTS AND THE EINSTEIN RELATION IN AMORPHOUS-SILICON

We propose an experimental procedure for testing the Einstein relation for carrier drift and diffusion in semiconductors exhibiting non-Gaus sian or dispersive transport. We present corresponding hole time-of-fl ight and steady-state photocarrier grating measurements in hydrogenate d amorphous silicon (a-Si:H). For a range of mobilities 10(-5)-10(-2) cm(2)/V s we find that our estimates of hole diffusion are approximate ly twice as large as predicted by the Einstein relation and the mobili ty measurements. We consider the deviation to represent an upper bound to any true failure of the Einstein relation for hole transport in a- Si:H.