THE ABNORMAL PHOTOCONDUCTION RESPONSE OF -Si:H FILMS WITH SANDWICH STRUCTURE

A series of curves of the photoconduction response under different field strengths and different degrees of illtimination has been measured and investigated. It is found that the rise and decay curves are abnormal under weaker fields. Analysis of these curves of photoconduction response shows that either rise curves or decay curves are composed of a spike-like and a quasi-exponential form. Considering the above fact, we suggest that these pheno-mena are due to the changes of distribution of the space charge in-Si:H films, when illumination turns on or off. It is felt that this paper is of universal significance for photosensitive materials with low mobilities and high resistivity.