Synthesis and low-temperature photoluminescence properties of SnO2 nanowires and nanobelts

Ultra-long rutile tin dioxide nanowires and nanobelts are synthesized by thermal oxidation of tin powder using gold film as the catalyst. Nanowire or nanobelts can be selectively produced by tuning the reaction temperature. The vapour-liquid-solid growth mechanism is proposed. The band gaps of the nanowires and nanobelts are 3.74 and 3.81 eV respectively, determined from UV/visible absorption spectral results. The SnO₂ nanowires show stable photoluminescence with two emission peaks centred at around 470 and 560 nm. Their wavelengths stay almost fixed while their intensities depend sensitively on the temperatures within the examination ranges from 10 to 300 K. The SnO₂ nanobelts show similar photoluminescence behaviours and the origin of the luminescence is discussed.