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

The ZnO nanowires (NWs) are grown by carbothermal reaction and SnO
2
shell layers are subsequently coated by vapor phase growth. The crystalline SnO
2
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-SnO
2
core-shell NWs sensor to 10 ppm NO
2
at 200°C was increased up to ∼33 times compared to those of ZnO NWs. The enhancement of gas responses to NO
2
was discussed in relation to the thin SnO
2
shell layer and core-shell configuration of NWs.