Synthesis and Characterization of Single-Crystalline SnO2 Nanowires

Tin oxide (SnO2) nanowires were synthesized on oxidized silicon substrates by thermal evaporation of tin grains at 900 degrees C in Ar flow at ambient pressure. Structural characterization using X-ray diffraction and transmission electron microscopy shows that SnO2 nanowires have a single crystal tetragonal structure. Scanning electron microscopy observation demonstrates that SnO2 nanowires are 30-200 nm in diameter and several tens of micrometers in length. The surface vibration mode resulting from the nanosize effect at 565.1 cm(-1) was found from the Fourier transform infrared spectrum. The formation of SnO2 nanowires follows a vapour-solid (VS) growth mechanism. The gas sensing measurements indicate that SnO2 nanowire gas sensor obtains peak sensitivity at a low operating temperature of 150 degrees C and shows reversible response to H-2 gas (100-1000 ppm) at an operating temperature of RT-300 degrees C.