Reverse Current Characteristics of Hydrogenated Amorphous Silicon-Crystalline Silicon Heterojunctions

Abstract

The electrical properties of heterojunctions of p-type a-Si:H and n-type c-Si have been investigated by measuring I–V and C–V characteristics. The C–V characteristics revealed that there was something (what is called interface defect states) to obstruct the spread of the depletion layer in c-Si at the interface of a-Si:H and c-Si. The I–V characteristics showed that these interface defect states assisted the generation of a reverse current. The calculation suggested that only the interface defect states near the midgap influenced the reverse current. Consequently, to realize a low dark current applicable to imaging devices, it was necessary to decrease the number of interface defect states.