Carrier transport in a position sensitive detector based on an ITO/a-Si:H/Pd structure

The carrier transport in ITO/a-Si:H/Pd position sensitive detector is studied experimentally and numerically. Hydrogenated amorphous silicon deposited by the homogeneous chemical vapour deposition process (HOMOCVD) is used as an active layer, A method which allows estimation of the a-Si:H electron trap density (N-t) and the effective electron diffusion length (L-n) in ITO/a-Si:H/Pd structure is presented. The method is based on the comparison between the experimentally measured dependencies and the calculated ones. For N-t and L-n the values: N-t = 7 x 10(15) cm(-3) and L-n = 0.5 cm are obtained. The relatively large value of L-n is a result of the separation of light generated carriers and the suppression of their recombination by the electric field in the a-Si:H layer. (C) 2001 Elsevier Science B.V. All rights reserved.