Shift of responsive peak in GaN-based metal-insulator-semiconductor photodetectors

A gallium nitride (GaN)-based metal-insulator-semiconductor (MIS) ultraviolet photodetector (PD) was fabricated on a sapphire substrate. It was found that the responsive peak of the GaN-based MIS PD redshifted with increasing negative bias, which has not been reported before. Also, the shift of the responsive peak has been interpreted in terms of the tunneling procedure of the photo-generated holes assisted by defects in the interfaces between the GaN layers and the SiNx layers.