Phase transformation in room temperature pulsed laser deposited TiO2 thin films

We report on the pulsed laser deposition of TiO2 thin films using an excimer laser at 308 nm and a Nd:YAG laser at 355 and 1064 nm wavelength on glass and Si(1 1 1) substrates at room temperature. Deposited films have been characterized using Auger electron spectroscopy (AES), scanning electron microscopy (SEM), and pre- and post-annealed X-ray diffraction (XRD). The atomic concentration ratio has been determined using AES. SEM images of films deposited on Si(1 1 1) showed the presence of TiO2 clusters/aggregates. The deposited films are observed to have characteristic phases at various wavelengths of deposition. The anatase–brookite or rutile–brookite phases dominate at 1064 nm after annealing the films in air whereas all three phases have been observed at 355 nm ablation without annealing the films. The different phases are observed to depend on the excitation temperature of the TiO2 plasma. The excitation temperature of 4.9±0.3 and 2.82±0.02 eV of the plasma is calculated at 355 and 1064 nm irradiation using optical emission spectrum in ambient atmosphere of oxygen.