Morphology-controlled synthesis and a comparative study of the physical properties of SnO2 nanostructures: from ultrathin nanowires to ultrawide nanobelts.

Controlled synthesis of one-dimensional materials, such as nanowires and nanobelts, is of vital importance for achieving the desired properties and fabricating functional devices. We report a systematic investigation of the vapor transport growth of one-dimensional SnO2 nanostructures, aiming to achieve precise morphology control. SnO2 nanowires are obtained when SnO2 mixed with graphite is used as the source material; adding TiO2 into the source reliably leads to the formation of nanobelts. Ti-induced modification of crystal surface energy is proposed to be the origin of the morphology change. In addition, control of the lateral dimensions of both SnO2 nanowires (from ~15 to ~115 nm in diameter) and nanobelts (from ~30 nm to ~2 µm in width) is achieved by adjusting the growth conditions. The physical properties of SnO2 nanowires and nanobelts are further characterized and compared using room temperature photoluminescence, resonant Raman scattering, and field emission measurements.