Synthesis and optical properties of tantalum oxide films prepared by ionized plasma-assisted pulsed laser deposition

In this work, tantalum oxide (TaOx) films were deposited on quartz glass substrates by pulsed laser deposition (PLD) and ionized plasma-assisted pulsed laser deposition (IPA-PLD). The effects of oxygen pressures and ionized oxygen plasma-assistance (IOPA) on the optical properties of deposited films have been studied. Ultraviolet-visible-near infrared (UV-VIS-NIR) scanning spectrophotometry was used to measure the transmittance of deposited films and to determine the optical band gap and absorption coefficient. Results show that the transmittance, absorption coefficient, band gap and chemical composition of deposited films reveal a strong dependence on the oxygen pressures and IOPA. Under optimum condition of IOPA, the refractive index of the synthesized film was 2.22 (at 633 nm wavelength), while an optical band gap of 4.18 eV was obtained. These two values compare very favorably with films produced by other methods.