Frabrication and properties of self-powered ultraviolet detectors based on one-demensional ZnO nanomaterials

Qi Jun-Jie, Xu Min-Xuan, Hu Xiao-Feng, Zhang Yue
2015 Wuli xuebao  
ZnO micro/nanowires were synthesized by chemical vapor deposition method. The morphology and structure of the products have been characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL) and micro-Raman scattering spectrometer, etc. Results show that the surface of the highly uniform ZnO wire is smooth and the as-synthesized ZnO wires show high crystal quality. Three types of UV detector are constructed using a single ZnO nanowire with different
more » ... ontact characteristics, and their corresponding performances are investigated systematically by using Keithley 4200-SCS and other equipments. All of the three different devices exhibit good rectifying characters and significant responsivity to ultraviolet light. The devices show self-driven features at zero bias. Compared with the devices made from Schottky contact and ZnO/PEDOT:PSS film, the present single ZnO nanowire/p-Si film devices with heterojunctions have the best selfpowered function, which can be attributed to the stronger built-in electric field as well as the smaller dark current due to the insulating layer on the p-Si film. At zero bias, the fabricated ZnO nanowire/p-Si film device can deliver a dark current of 1.2 × 10 −3 nA and a high photosensitivity of about 4.5 × 10 3 under UV illumination. The response of the devices made from ZnO nanowire/p-Si film to UV illumination in air is pretty fast with the rise time of about 0.7 s and the fall time of about 1 s, which could be attributed to the fact that the photo-generated electron-hole pairs in the depletion layer is quickly separated by the built-in electric field, leading to a rapid response speed and a larger photocurrent. Comparison among the three kinds of devices indicates that the devices made from ZnO nanowire/p-Si film are the best candidate for UV detectors.
doi:10.7498/aps.64.172901 fatcat:pzsujdhgwberrhhlr4e2ao6spe