Fabrication of nanoparticles of anatase TiO2 by oxygen-supplied pulsed laser deposition

Nanoparticles of titanium oxides have been fabricated by ablating a Ti target with pulsed CO2-laser deposition in Ar-diluted oxygen environments. The pulse energy and repetition rate of the CO2 laser (wavelength 10.6 μm) are 0.44 J/cm2 per pulse and 50 Hz, respectively. During the focused laser irradiates the Ti target, Ar and O2 gases are supplied into the irradiation chamber. The gas pressure is varied in a range of 1x103 to 1x105 Pa. The flow rates of Ar and O2 gases are adjusted in ranges of 75-83 and 3.3-8.3 cm3/s, respectively. Above 3x104 Pa, the laser irradiation creates nanosized spherical particles of titanium dioxide. The nanospheres are characterized by transmission electron microscopy (TEM) to be of the anatase type. Each nanoparticle consists of a single crystal or single-crystalline domains. The particle size slightly increased with increasing the gas pressure, irrespective of the flow rate. The results demonstrate that nanoparticles of anatase TiO2 are created by the reactive pulsed laser deposition (PLD)