Synthesis of Single-Crystal TiO ₂ Nanowire Using Titanium Monoxide Powder by Thermal Evaporation

TiO ₂ nanowires were synthesized successfully in a large quantity by thermal evaporation using titanium monoxide powder as precursor. X-ray diffraction results showed that all the products were pure rutile phase of TiO ₂. According to microstructural observations, the nanowires have two typical morphologies, a long straight type and a short tortuous type. The straight nanowires were obtained at a wide temperature range of 900-1050 °C, while the tortuous ones were formed below 900 °C. Transmission electron microscopy characterization revealed that both the straight and the tortuous nanowires are single-crystal rutile TiO ₂. The preferential growth direction of the nanowires was determined as [110] orientation according to electron diffraction and high-resolution image analyses. The morphological change of TiO ₂ nanowires was discussed by considering the different atomic diffusion rates of Ti atoms caused by the phase transformation in Ti substrate at around 900 °C.