High storage and operational stability self-powered UV photodetector based on p-CuI/n-GaN heterojunction prepared by thermal evaporation method

Self-powered ultraviolet (UV) photodetectors play an important role in environmental monitoring, aerospace and other fields because of the advantage of effective light response without an external power supply. Herein, a p-CuI/n-GaN heterojunction UV photodetector with self-powered function is constructed by vacuum thermal evaporation method. At 365 nm UV irradiation, the photodetector has an on/off ratio of 7536, a large photo-current (similar to 35 mA) and a fast response time (rise/decay time of 10.46/10.35 ms) at zero bias. There was no significant decrease in photocurrent during the 100 on/off cycles of the continuous test, and the photocurrent of the photodetector can maintain 93.17% of the initial value after continuous operation for 15 h without bias voltage. The rise in ambient temperature exhibits a negative effect on the UV photodetector, but when it is naturally cooled from 80 degrees C to room temperature (RT), the photocurrent can restore to 95% of the original level. Furthermore, the photodetector maintains superior stability even after being stored in air for 3 months of without package. This work not only proves the controllable preparation strategy of CuI thin films, but also provides an efficient structure for self-powered UV photodetectors with high operational and storage stability.