Balancing the Transmittance and Carrier‐Collection Ability of Ag Nanowire Networks for High‐Performance Self‐Powered Ga<sub>2</sub>O<sub>3</sub> Schottky Photodiode
Pengju Tan, Xiaolong Zhao, Xiaohu Hou, Yangtong Yu, Shunjie Yu, Xiaolan Ma, Zhongfang Zhang, Mengfan Ding, Guangwei Xu, Qin Hu, Nan Gao, Haiding Sun, Wenxiang Mu, Zhitai Jia, Xutang Tao, Shibing Long
Abstract
Abstract Self‐powered solar‐blind photodiodes with convenient operation, easy fabrication, and weak‐light sensitivity, are highly desired in environmental monitoring and deep space exploration. Ga 2 O 3 with its bandgap directly corresponding to solar‐blind waveband is a promising candidate material for solar‐blind photodetection. However, ever‐reported self‐powered Ga 2 O 3 photodiodes suffer unsatisfactory photoresponse performance, owing to unideal interface and electrode transmittance. Here, Ag nanowire (AgNW) networks with excellent solar‐blind ultraviolet transmittance are introduced to form self‐powered AgNW–Ga 2 O 3 photodiodes with sharp Schottky interfaces. The tradeoff between solar‐blind ultraviolet transmittance and carrier‐collection ability of the sparse AgNW network is systematically studied and the AgNW density is optimized for the best photoresponse. Expansion of depletion region outwards the AgNW–Ga 2 O 3 contact and the field crowding effect facilitate the high photoresponse. As a result, the champion AgNW–Ga 2 O 3 Schottky photodiode exhibits excellent sensitivity for weak‐light detection, including considerable responsivity of 14.8 mA W –1 , ultrahigh photo‐to‐dark‐current ratio above 1.2 × 10 5 , high rejection ratio ( R 254 nm / R 365 nm ) of 2.6 × 10 3 , and fast response speed (rise/decay time of 20/24 ms) under self‐powered mode. Balancing the transmittance and carrier‐collection ability of elaborate electrode provides an alternative strategy to achieve high‐performance self‐powered Ga 2 O 3 photodetectors for future weak‐light‐sensitive optoelectronic systems.