Enhanced self-powered CsCu2I3/GaN heterojunction UV photodetectors based on highly oriented CsCu2I3 thin films

Abstract

Using the thermal evaporation method, highly oriented CsCu2I3 thin films were prepared on GaN and quartz with CuI interlayers by adjusting the ratio of CsI:CuI. The mechanism of the growth of CsCu2I3 thin films on CuI interlayer was investigated. The enhanced CsCu2I3/GaN heterojunction UV photodetectors were constructed using the CsCu2I3 thin films deposited on the GaN epitaxial film with a 5 nm CuI interlayer. The fabricated heterojunction photodetectors demonstrated exceptional self-powered photoresponse characteristics, including a high on/off ratio of 2.5 × 104 at 0 V, peak responsivity of 46.91 mA/W and peak specific detectivity of 3.80 × 1012 Jones at 360 nm. Furthermore, the response speed and air stability of the device were significantly improved. This study presents a new approach for producing highly oriented CsCu2I3 films for stable, high-performance, and environmentally friendly optoelectronic devices.