High-performance self-powered ultraviolet photodetector in SnO2 microwire/p-GaN heterojunction using graphene as charge collection medium

Graphene monolayer has been extensively applied as a transparency electrode material in photoelectronic devices due to its high transmittance, high carrier mobility, and ultrafast carrier dynamics. In this study, a high-performance self-powered photodetector, which is made of a SnO2 microwire, p-type GaN film, and monolayer graphene transparent electrode, was proposed and fabricated. The detector is sensitive to ultraviolet light signals and illustrates pronounced detection performances, including a peak respon-sivity -223.7 mA W -1 , a detectivity -6.9 x 10 12 Jones, fast response speed (rising/decaying times -18/580 mu s), and excellent external quantum efficiency -77% at 360 nm light illumination without exter-nal power supply. Compared with the pristine SnO2/GaN photodetector using ITO electrode, the device performances of responsivity and detectivity are significantly increased over 6 x 10 3 % and 3 x 10 3 %, respectively. The performance-enhanced characteristics are mainly attributed to the high-quality het-erointerface of n-SnO2/p-GaN, the highly conductive capacity, and the unique transparency of graphene electrodes. Particularly, the built-in potential formed at the SnO2/GaN heterojunction interface could be strengthened by the Schottky potential barrier derived from the graphene electrode and SnO2 wire, en-hancing the carrier collection efficiency through graphene as a charge collection medium. This work is of great importance and significance to developing excellent-performance ultraviolet photodetectors for photovoltaic and optoelectronic applications in a self-powered operation manner.(c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )