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

Abstract 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 C 2 H 5 OH 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 C 2 H 5 OH and an unprecedentedly high response (28.8) even to 0.25 ppm C 2 H 5 OH. The enhancement of the gas response and selectivity to C 2 H 5 OH was attributed to Mg-doping-induced decrease of the charge carrier concentration, the change of nanowire thickness/morphology, and the catalytic promotion of the C 2 H 5 OH sensing reaction.