A Simple Passivation Technique for AlGaN/GaN Ultraviolet Schottky Barrier Photodetector

This letter demonstrates and investigates AlGaN/GaN ultraviolet photodetector (UV-PD) with a simple passivation process. The hydrogen peroxide (H₂O₂) oxidation technique is adopted to complete the passivation. The results of chemical analysis suggest that the Al and Ga dangling bonds react with the oxygen atoms. This passivation process effectively reduces the side-wall surface states, which also suppress the dark current to 11 pA. In addition, the photo response and the UV to visible rejection ratio of the PD with H₂O₂ passivation process are enhanced to 8.1×10^-3 A/W and 2.3×10³ when the PD is biased at -10 V. The noise equivalent power and the detectivity are determined to be 1.63×10^-8 W and 1.33×10⁸ cmHz^0.5W^-1. The simple passivation technique improves the AlGaN/GaN UV PD performances effectively.