Low temperature tin oxide (SnO2) nanowire gas sensor

Abstract

In present work, we report the synthesis of SnO2 nanowires on gold catalyzed silicon substrate and implementation of these grown SnO2 nanowires as a sensing element for methanol sensing. The SnO2 nanowires were synthesized by using thermal evaporation method. The growth of SnO2 nanowires was carried out on gold catalyzed silicon (Au/Si) substrate by thermal evaporation of a mixture of SnO2 and graphite powders in Argon (Ar) ambience at a temperature of 1050°C. The growth of SnO2 nanowires takes place at atmospheric pressure. The surface morphology study reveals the growth of SnO2 nanowires (diameter~ 300 nm, length~ 50 μm) on the Au coated silicon substrate. The XRD analysis concludes that synthesized SnO2 nanostructures show polycrystalline nature with tetragonal rutile structure. The vapor-liquid-solid (VLS) growth mechanism of SnO2 nanowires were also confirmed by EDX spectra. The SnO2 nanowires were used to fabricate single SnO2 nanowire based methanol gas sensor. The result reveals that the device exhibit the resistance change from 23 MΩ to 10 KΩ upon exposing to 200 ppm concentration of methanol gas at 100°C. This sensing behaviour offers a suitable application of the SnO2 nanowire sensor for detection of methanol gas.