High-sensitivity GaN UV photodetector integrated with graphene
Jing Wang, Hanxue Jiao, Xudong Wang, Fuhao Liu, Zhidan Diao, Menglin Liu, Wenxin Li, Ling Wang, Yan Chen, Tie Lin, Hong Shen, Xiangjian Meng, Xiangyang Li, Junhao Chu, Jianlu Wang
Abstract
Ultraviolet (UV) photodetectors are critical for a wide range of applications, where high sensitivity and low dark current are essential for accurate detection. This study presents a graphene-based p-i-n UV photodetector with a Gr/i-GaN/n-GaN structure, aimed at improving UV detection performance by improving sensitivity and reducing dark current. Graphene, as a p-type material, enhances carrier mobility and reduces recombination, while leveraging the wide bandgap properties of i-GaN and n-GaN for efficient UV absorption. The experimental results show that the graphene/i-GaN/n-GaN photodetector achieves a maximum photoresponsivity of 20.6 A/W, detectivity of 2.0 × 1012 cm·Hz1/2·W−1, and external quantum efficiency of 75.25%, indicating efficient light-to-current conversion performance. The integration of graphene in the p-i-n structure significantly reduces the dark current to 2.68 × 10−13 A, improving both the transient response and the overall efficiency of the device. These findings underscore the effectiveness of the graphene/i-GaN/n-GaN structure in improving UV photodetection performance. By combining the high mobility of graphene and the wide bandgap properties of GaN, this work demonstrates potential for application in graphene-based p-i-n photodetectors as a viable approach for future UV sensing applications, offering enhanced performance and stability for precise UV detection across varying conditions.