High-Photoresponsivity Self-Powered a‑, ε‑, and β‑Ga2O3/p-GaN Heterojunction UV Photodetectors with an In Situ GaON Layer by MOCVD

• Published in: ACS applied materials & interfaces Vol. 14; no. 30; pp. 35194 - 35204
• Main Authors: Ma, Yongjian, Chen, Tiwei, Zhang, Xiaodong, Tang, Wenbo, Feng, Boyuan, Hu, Yu, Zhang, Li, Zhou, Xin, Wei, Xing, Xu, Kun, Mudiyanselage, Dinusha, Fu, Houqiang, Zhang, Baoshun
• Format: Journal Article
• Language: English
• Published: American Chemical Society 03.08.2022
• Subjects: Surfaces, Interfaces, and Applications; self-powered UV photodetectors; GaON; Ga2O3/p-GaN; high responsivity; p−n junction
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c06927

In this paper, self-powered ultraviolet (UV) photodetectors with high response performance based on Ga2O3/p-GaN were fabricated by metal–organic chemical vapor deposition (MOCVD). The effects of different crystal phases of Ga2O3 (including a, ε, ε/β, and β) grown on p-GaN films on the performance of photodetectors were systematically studied. Moreover, an in situ GaON dielectric layer improved the responsivity of Ga2O3/p-GaN photodetectors by 20 times. All Ga2O3/p-GaN photodetectors showed self-power capability without bias. An ultralow dark current of 3.08 pA and a I photo/I dark ratio of 4.1 × 103 (1.8 × 103) under 254 nm (365 nm) light were obtained for the β-Ga2O3/p-GaN photodetector at 0 V bias. Furthermore, the β-Ga2O3/p-GaN photodetector showed excellent sensitivity with a high responsivity of 3.8 A/W (0.83 A/W), a fast response speed of 66/36 ms (36/73 ms), and a high detectivity of 1.12 × 1014 Jones (2.44 × 1013 Jones) under 254 nm (365 nm) light at 0 V bias. The carrier transport mechanism of the Ga2O3/p-GaN self-powered photodetector was also analyzed through the device energy band diagram. This work provides critical information for the design and fabrication of high-performance self-powered Ga2O3/p-GaN UV photodetectors, opening the door to a variety of photonic systems and applications without an external power supply.