Synthesis of nanophase TiO2 by ion beam sputtering and cold condensation technique

Nanoparticles of TiO2 have been synthesized by an ion beam sputtering-cold condensation (IBS-CC) technique. A sintered TiO2 was sputtered by an ion beam (Kaufman source, 900 eV, Ar+ ions) and the ejected atoms/radicals were made to condense on a Si(100) substrate herd at -50 degrees C. X-ray diffraction data showed that the average particle size in the as-deposited material is about 3.5 +/- 1.5 nn. Upon annealing at 600 degrees C for five hours, the average particle size was seen to increase to about 70 +/- 10 nm. Further annealing for one hour at 900 degrees C led to increase of average particle size to 200 +/- 20 nm. X-ray spectroscopy, Raman spectroscopy and photoluminescence data have been used to reveal the presence and relative concentrations of rutile and anatase phases of TiO2 in the as-deposited and annealed samples. The IBS-CC method is found to yield a more compact particle size distribution as compared to the method based on Laser Ablation.