GaN-based ultraviolet photodiodes with a semi-insulating Mg-doped GaN cap layer were fabricated and characterized. Dark leakage current of the aforementioned photodiodes was much smaller than that of the conventional ones without the Mg-doped GaN cap layer due to a thicker and higher potential barrier and less amounts of interface states after inserting the Mg-doped GaN cap layer. The ultraviolet to visible rejection ratio is 3.44 ×103 by inserting a semi-insulating Mg-doped GaN cap layer with a -1 V applied bias. In this study, we also discuss the noise characteristics. It was found that minimum noise equivalent power and maximum detectivity of our photodiode were 1.2 × 10-12 W and 9.34 × 1011 CmHz 0.5W-1, respectively.
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering