Highly-Rectifying Graphene/GaN Schottky Contact for Self-Powered UV Photodetector
Shanyong Wang, Rongsheng Chen, Yuan Ren, Yawei Hu, Ziqi Yang, Changjian Zhou, Yuanjie Lv, Xing Lü
Abstract
In this study, we demonstrated self-powered fast-response ultraviolet (UV) detection based on a highly-rectifying graphene/GaN Schottky contact. The device was fabricated by mechanically transferring a monolayer graphene onto lightly-doped GaN and showed excellent Schottky behaviors, including a high rectification ratio (> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> ), a close-to-unity ideality factor and a relatively high Schottky barrier height (1.01 eV). At zero bias, the graphene/GaN Schottky photodiodes exhibited a strong photovoltaic response to UV illumination with a competitively short rise/decay time of 221/546 μs. A trap-associated photoconductive mechanism started to dominate the device's response when its bias went beyond -1 V, which could be identified from the suddenly increased responsivity and response time.