Pulsed laser deposition of anatase and rutile TiO2 thin films

• Published in: Surface & coatings technology 2007-06, Vol.201 (18), p.7713-7719
• Main Authors: MUMGESAN, S, KUPPUSAMI, P, PARVATHAVARTHINI, N, MOHANDAS, E
• Format: Article
• Language: English
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Production techniques; Surface treatment; Surface treatments
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2007.03.004

The investigation deals with the preparation of both anatase and rutile thin films from a sintered rutile target of TiO2 by pulsed laser ablation technique. Microstructural characterization of the sintered target was carried out using X-ray diffraction and AC impedance spectroscopy. Thin films of titania were deposited on (111) Si substrates at 673K in the laser energy range 200-600mJ/pulse at two different conditions: (i) deposition at 3.5X10-5mbar of oxygen, and (ii) deposition at an oxygen partial pressure of 0.1mbar. The influence of laser energy and oxygen addition on the film growth has been studied. X-ray diffraction analysis of the films indicated that the films are single phasic and nano crystalline. Titania films deposited in the energy range 200-600mJ/pulse at a base pressure of 5X10-5mbar are rutile with particle sizes in the range 5-10nm, whereas the films formed at the oxygen partial pressure 0.1mbar are anatase with particle sizes in the range 10-24nm. In addition, at higher energies, a significant amount of particulates of titania are found on the surface of the films. The change in the microstructural features of the films as a function of laser energy and oxygen addition is discussed in relation with the interaction of the ablated species with the background gas.