Influence of defects in n−-GaN layer on the responsivity of Schottky barrier ultraviolet photodetectors

The influence of defects on the responsivity of GaN Schottky barrier ultraviolet photodetectors with n−-GaN∕n+-GaN layer structures is investigated. It is found that employing undoped GaN instead of Si-doped GaN as the n−-GaN layer brings about a higher responsivity due to a lower Ga vacancy concentration. On the other hand, the dislocations may increase the recombination of electron-hole pairs and enhance the surface recombination in the photodetectors. Employing undoped GaN and reducing the dislocation density in the n−-GaN layer are necessary to improve the responsivity of Schottky barrier photodetectors.