Highly integrated SNO2 nanotubes using templated ZNO nanowires for low power gas sensors

Abstract

We have developed highly sensitive, low power gas sensors consisting of beam-shaped, suspended microheaters and locally synthesized 1-D metal oxide nanostructures. In-situ localized hydrothermal synthesis method was utilized to grow ZnO nanowires on the Joule-heated region. Also, liquid phase deposition (LPD) process enabled to formulate SnO2 thin film on the surface of ZnO nanowires and to etch ZnO out at the same time. Therefore, we could fabricate highly integrated and sensitive SnO2 nanotubes on the selective region less than 502 μm2. Due to the small and suspended heating area, operating power of the gas sensor was less than 10 mW at 300 °C. Also, the sensitivity (Rair/Rgas) of SnO2 nanotubes for H2S gas was around 6 times larger than that of pre-processed ZnO nanowires.