Vapor-phase growth of urchin-like Mg-doped ZnO nanowire networks and their application to highly sensitive and selective detection of ethanol

Urchin-like Mg-doped ZnO nanowire networks were prepared by MgO-seeded vapor-phase growth of ZnO nanowires, and their potential as gas-sensing materials was investigated. The response (resistance ratio) of the urchin-like Mg-doped ZnO nanowire networks to 5 ppm C2H5OH at 350 °C was as high as 343, which is significantly higher than that of pure ZnO nanowire networks (7.0). In addition, the Mg-doped ZnO nanowire network sensors showed excellent selectivity to C2H5OH and an unprecedentedly high response (28.8) even to 0.25 ppm C2H5OH. The enhancement of the gas response and selectivity to C2H5OH was attributed to Mg-doping-induced decrease of the charge carrier concentration, the change of nanowire thickness/morphology, and the catalytic promotion of the C2H5OH sensing reaction.