Fig. 4From: Synthesis and gas sensing properties of membrane template-grown hollow ZnO nanowiresNormalized resistance curves of hollow ZnO NW sensors with different surface areas towards 0.1, 1, and 10 ppm of a CO and b NO2 at 400 °C. c Response versus surface area for hollow ZnO NWs sensor with different surface areas at different concentrations of CO and NO2 gasesBack to article page