The influence of threading dislocations upon the properties of GaN-based metal-semiconductor-metal ultraviolet photodetectors was investigated. It was found that screw dislocations had a strong influence upon the dark current of the photodetectors, while edge dislocations had a predominant effect upon their response. The dark current increased as the screw dislocation density increased, due to their lowering of the Schottky barrier height. However, the response of the photodetectors decreased with increasing edge dislocation density because of the dangling bonds along those edge dislocation lines, which enhanced the recombination of photogenerated electron-hole pairs. The results suggested that reducing both the screw and edge dislocation densities was an effective way to improve the photo-electric property of GaN-based metal-semiconductor-metal ultra-violet photodetectors.

Influence of Threading Dislocations on GaN-Based Metal-Semiconductor-Metal Ultraviolet Photodetectors. D.Li, X.Sun, H.Song, Z.Li, Y.Chen, G.Miao, H.Jiang: Applied Physics Letters, 2011, 98[1], 011108