Enhanced hydrogen sensitivity of WO3-core/ZnO-shell nanorods

초록

WO3-core/ZnO-shell nanorods were synthesized by a two–step process comprising thermal evaporation of WO3 powders and atomic layer deposition of ZnO. Scanning electron microscopy images exhibited a rod-like morphology with diameters in a range from a few tens to a few hundreds of nanometers and lengths up to a few tens of micrometers. The gas sensors fabricated from multiple networked WO3-core/ZnO-shell nanorods showed the enhanced electrical responses to hydrogen gas at room temperature. The sensitivity of the core-shell nanorods was improved by a factor of higher than 30 at hydrogen concentrations in a range from 200 to 2000 ppm at room temperature. In addition, the mechanism for the improvement in the gas sensing characteristics of WO3 nanorods by ZnO sheathing are discussed