Enhanced performance of photoelectrochemical type ultraviolet photodetector by constructing a KNbO3/ZnO heterojunction

Ultraviolet (UV) radiation has applications in many fields such as environmental monitoring and communication. Hence, high performance ultraviolet photodetectors (UVPDs) are needed to monitor UV radiation. In this work，photoelectrochemical (PEC) type based on KNbO3/ZnO heterojunctions have been fabricated because of their excellent performance and the appropriate band structures of KNbO3 and ZnO. Owing to the internal self-polarization of KNbO3 and the formation of the KNbO3/ZnO heterojunctions, the PEC UVPDs possess higher performances than PEC UVPDs based on pure ZnO and KNbO3. The responsivity of the developed PEC UVPDs based on KNbO3/ZnO reached 0.1 A/W at 360 nm UV light. Meanwhile, the rise and decay time of these PEC UVPDs based on KNbO3/ZnO heterojunctions were 8 ms and 11 ms, respectively. Moreover, the device has an excellent linear wavelength response, roughly from 320 to 400 nm. This work shows that the PEC UVPDs based on KNbO3/ZnO heterojunctions have high sensitivity and responsivity, rapid response, indicating their good potential in UV detection.