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

Developing new photodetectors with good photoresponse, high stability, flexibility, and minimalization is ur-gently 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 Zn2SnO4layer at the large interface of ZnO-SnO2 heterojunctions. Upon exposure to UV light with power density of 24 mu W 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 degrees. The combined utilization of electrospinning and photolithography is convenient to fabricate flexible UV photodetectors.