A high responsivity UV photodetectors based on ZnO quantum dots/ZnO nanowires homojunction

Ultraviolet (UV) photodetectors have attracted increasing attention due to their excellent performance and wide application in civil and defense fields in recent decades. At present, most UV photodetectors have the problem of lattice mismatch in functional semiconducting materials, which hinders the photoelectric transmission and affects device performance. The preparation of highly responsive UV detectors still faces significant challenges. Here, we present the prepare high-performance UV photodetectors utilizing homojunction device structures, wherein zinc oxide (ZnO) quantum dots (QDs) are employed to decorate ZnO nanowires to enhance the photoelectric responsivity. Moreover, we investigated the impact of ZnO quantum layers on the ZnO-based homojunction UV photodetectors to further optimize the device performance. Compared with pure ZnO nanowire photodetectors, the ZnO quantum dots/ZnO nanowires (ZnO QDs-NWs) homojunction photodetector exhibits a significantly enhanced responsivity, which is 12 times more than that of pure ZnO nanowire photodetectors. Moreover, ZnO QDs-NWs homojunction photodetectors demonstrate a higher detection rate. The performance enhancement benefited from the existence of I-type band structure in the contact surface between QDs and nanowires, where a large number of excited charge carriers can be injected from ZnO QDs into ZnO nanowires. In summary, this work introduces a straightforward and highly responsive UV photodetector based on ZnO QDs-NWs homojunction, which has the potential to develop highly responsive UV photodetectors.