Synthesis and gas sensing characteristics of highly crystalline ZnO-SnO2 core-shell nanowires

Abstract The ZnO–SnO 2 core–shell nanowires (NWs) were synthesized by a continuous two-step vapor growth method at different synthesis temperatures. A crystalline 15–20 nm-thick, SnO 2 shell layer was pseudo-epitaxially coated on ZnO NWs with a diameter of 50–80 nm. The gas response of the ZnO–SnO 2 core–shell NW sensor to 10 ppm NO 2 reached ∼33 times enhancement compared to that of the ZnO NWs at 200 °C. In addition, the ZnO–SnO 2 core–shell NW sensors showed selective detection to NO 2 at 200–300 °C and to C 2 H 5 OH at 400 °C. The enhanced gas responses to NO 2 and C 2 H 5 OH are discussed in relation to the thin SnO 2 shell layer and core–shell configuration of the NWs.