ZnO-SnO2 core-shell nanowire networks and their gas sensing characteristics

The ZnO nanowires (NWs) are grown by carbothermal reaction and SnO2 shell layers are subsequently coated by vapor phase growth. The crystalline SnO2 shell layer with the thickness of 5–20 nm was uniformly coated on the ZnO NWs with the diameter of 50–100 nm. The gas response of ZnO-SnO2 core-shell NWs sensor to 10 ppm NO2 at 200°C was increased up to ∼33 times compared to those of ZnO NWs. The enhancement of gas responses to NO2 was discussed in relation to the thin SnO2 shell layer and core-shell configuration of NWs.