Light sensitive semiconductor device for holding electrical charge therein

摘要

In a semiconductor device intended to hold an electric charge due to being exposed to light, a photoconductive layer having a surface capable of being electrically charged is provided. A conductive base member is intended to support the photoconductive layer and permits the flow of electric charge therethrough. Between the photoconductive layer and the conductive base member, a first barrier layer and a second barrier layer are provided, the first barrier layer having a predetermined resistivity and being formed of a semiconductor serving to control the flow of an electric charge between the photoconductive layer and the conductive base member, and said second barrier layer having a resistivity which is higher than that of the first barrier layer and also being formed of a semiconductor serving to control the flow of an electric charge between the photoconductive layer and conductive base member. By the actions of the first and second barrier layers, it is possible to obtain a satisfactory percentage of charge holding.