Improved H 2 S gas sensing properties of ZnO nanorods decorated by a several nm ZnS thin layer

To avoid a spontaneous reaction between ZnO gas sensing materials and detected H2S gas, ZnO nanorods decorated with a several nm ZnS thin layer were designed. The ZnS-decorated layer was prepared by passivating oriented ZnO nanorods in a H2S atmosphere. The effect of the passivation processes on the H2S sensing properties was investigated. It was found that ZnO nanorods decorated with a 2 nm-thick ZnS layer possessed a repeatable and superior response to ppm-level H2S at room temperature. Moreover, a confinement effect was proposed to explain the improved sensing properties of the decorated ZnO nanorods.