Novel growth of CuO-functionalized, branched SnO2 nanowires and their application to H2S sensors

Abstract

A novel growth method for CuO-functionalized, branched tin oxide (SnO2) nanowires was developed on the basis of a Cu-triggered tip-growth vapour-liquid-solid (VLS) process during annealing of Cu-coated SnO2 nanowires. The variation in annealing temperature changed the morphology, in which higher temperatures (>= 500 degrees C) are favourable for the formation of branches. From the observation of tip nanoparticles, we revealed that the growth of branches at 500 and 700 degrees C was dominated by base-growth and tip-growth VLS processes, respectively. The tip nanoparticles at 700 degrees C were mainly comprised of a CuO phase. We have demonstrated the potential applicability of the CuO-functionalized, branched SnO2 nanowires to H2S sensors. CuO functionalization significantly enhanced the response to H2S. In sharp contrast, it degraded the response to NO2, suggesting their selective sensing performance to H2S.