Abstract

for th the va iO2 fi n mic ts nan tion tr spectr ts ind 304 A t rece microscope HAADF/STEM revealed that the TiO2 film possessed 99.99% was introduced into the quartz reactor. The system was l Soc 23.00 Downlomany Au nanocrystals, of which the average size was 10 nm. Moreover, many nanowires, studded with these Au nanocrystals, were found throughout the sample. We propose this two-step vacuum process to implant Au nano-crystals into TiO2 film. However, Ti is a refractory material with a high melting point of 1668°C,3 thus the question is how to synthe-size TiO2 nanowires by a vapor deposition process thermal evapo-ration at a substrate temperature of 850°C. To consider this issue in terms of vapor pressure, note that vapor pressure p is generally expressed as4 log p = a T + b log T + c + d where a, b, c, and d are constants determined by a variety of substances.5 The vapor pressure of Ti is 10−3 Torr at 1577°C, thus fabrication of TiO2 nanostructures by the vapor-phase method is a challenge. To address this challenge, a previous study reported that a predeposited TiO2 film can be employed to grow TiO2 nanowires on activated nucleation sites.6 These nanowires were synthesized held at these temperatures with a pressure of 10−3 Torr for 1 h. In the second step, the vacuum system was switched to 760 Torr by opening the chamber to atmospheric pressure. The system was maintained at this pressure for 1 h. After the process was finished,Implantation, Characteriza