Enhanced property of flexible UV photodetectors based on electrospinning ZnO–SnO2 heterojunction nanofibers by the formation of Zn2SnO4

Abstract

Developing new photodetectors with good photoresponse, high stability, flexibility, and minimalization is urgently demanded facing the rapid development of optical technology. In this work, ZnO–SnO2 heterojunction nanofibers are synthesized by electrospinning. The flexible UV micro-photodetector is fabricated by combining ZnO–SnO2 heterojunction nanofibers with photolithography-patterned Au microelectrodes on PI substrate. An extremely low dark current (∼10−11 A) is obtained due to the formation of Zn2SnO4 layer at the large interface of ZnO–SnO2 heterojunctions. Upon exposure to UV light with power density of 24 μW cm−2, the photodetector exhibits high on–off ratio of ∼104, high responsibility of 267 A W−1, and fast response speed of 2.75 s. The photodetector has good photoelectric properties and high UV selectivity. Moreover, the flexibility of the UV photodetector is demonstrated. The photoresponse remains ∼60% of the initial level even under a large bending angle of 45°. The combined utilization of electrospinning and photolithography is convenient to fabricate flexible UV photodetectors.