Self-powered p-CuI/n-GaN heterojunction UV photodetector based on thermal evaporated high quality CuI thin film
Zhiying Zhou, Fengzhou Zhao, Cheng Wang, Xiaoxuan Li, Shunli He, Dan Tian, Dengying Zhang, Lichun Zhang
Abstract
With vacuum thermal evaporation, the CuI film was deposited on quartz and n-GaN substrates, and the morphology, crystalline structure and optical properties of the CuI films were investigated. According to the XRD results, the CuI film preferentially grew along [111] crystal orientation on the GaN epilayer. With Au and Ni/Au ohmic contact electrodes fabricated on CuI and n-GaN, a prototype p-CuI/n-GaN heterojunction UV photodetector strong UV spectral selectivity was created. At 0 V and 360 nm front illumination (0.32 mW/cm 2 ), the heterojunction photodetector displayed outstanding self-powered detection performance with the responsivity ( R ), specific detectivity ( D *), and on/off ratio up to 75.5 mA/W, 1.27×10 12 Jones, and ∼2320, respectively. Meanwhile, the p-CuI/n-GaN heterojunction photodetector had excellent atmosphere stability.