Synthesis of Single-Crystal TiO2 Nanowire Using Titanium Monoxide Powder by Thermal Evaporation

TiO2 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 TiO2. 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 TiO2. 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 TiO2 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.