Room temperature, ppb-level NO(2) gas sensing of multiple-networked ZnSe nanowire sensors under UV illumination

Reports of the gas sensing properties of ZnSe are few, presumably because of the decomposition and oxidation of ZnSe at high temperatures. In this study, ZnSe nanowires were synthesized by the thermal evaporation of ZnSe powders and the sensing performance of multiple-networked ZnSe nanowire sensors toward NO(2) gas was examined. The results showed that ZnSe might be a promising gas sensor material if it is used at room temperature. The response of the ZnSe nanowires to 50 ppb–5 ppm NO(2) at room temperature under dark and UV illumination conditions were 101–102% and 113–234%, respectively. The responses of the ZnSe nanowires to 5 ppm NO(2) increased from 102 to 234% with increasing UV illumination intensity from 0 to 1.2 mW/cm(2). The response of the ZnSe nanowires was stronger than or comparable to that of typical metal oxide semiconductors reported in the literature, which require higher NO(2) concentrations and operate at higher temperatures. The origin of the enhanced response of the ZnSe nanowires towards NO(2) under UV illumination is also discussed.