Highly Sensitive Light-induced Memory Effect with Amorphous Se-SnO(2) Heterojunction.

The light-induced memory effect in amorphous selenium films is studied by fabricating them into a sort of heterojunction (Se-SnO(2)) so as to be able to apply the bias voltage together with the laser beam irradiation for memory. Under the reverse bias voltage, a region of high electric field is formed in the selenium film near the junction. Remarkable enhancement in the photo-induced image spot is achieved if an appropriate bias voltage is applied simultaneously, indicating the sensitization of the memory effect due to the photocurrent induced by the high electric field in the selenium film.