© Applied Science Innovations Pvt. Ltd., India Carbon – Sci. Tech. 8/2(2016)1-8 1 RESEARCH ARTICLE Received:10/03/2016, Accepted:15/04/2016 ------------------------------------------------------------------------------------------------------------------------------ Characterization of TiO 2 thin films deposited by using dc magnetron sputtering Nalin Prashant Poddar (*) , S. K. Mukherjee Department of Physics, Birla Institute of Technology, Mesra, Ranchi - 835215, India. Abstract: Titanium dioxide thin films were deposited on silicon (111) and glass substrates by using direct current (dc) magnetron sputtering system. Thin films were deposited with different O 2 gas flow rate (1, 3, 9, 12 sccm) while keeping Ar gas flow rate constant at 30 sccm. The samples exhibit amorphous phase as deposited and become polycrystalline at 350ºC. X-ray diffraction (XRD) studies confirmed existence of anatase and rutile phase after post deposition annealing. As deposited films were transparent and their band gap increases with increase in oxygen gas flow rate. Fourier transform infrared (FTIR) spectroscopy data confirmed the existence of Ti-O band present in deposited films. Keywords: Titanium dioxide, thin films, anatase, rutile, XRD, UV-Vis, FTIR. ------------------------------------------------------------------------------------------------------------------------------------------------ 1. Introduction: Titanium dioxide (TiO 2 ) is a wide band gap semiconductor which has many potential applications. TiO 2 , especially in thin film form, has drawn attention over the years because of its interesting optical, photocatalytic and electronic properties. Its high refractive index makes it useful in optical coatings and transparent electronics. Due to high dielectric constant and high resistivity it has drawn much attention for use in fabricating capacitors in microelectronic devices. Because of high chemical stability and modest band gap, TiO 2 thin films are widely used as photocatalysts, gas-sensing agents and as active component in dye-sensitized solar cells [1, 2]. TiO 2 is known to exist in three crystalline polymorphs: rutile (R-tetragonal) (a = 4.593 Å, c = 2.959 Å), anatase (A-tetragonal) (a = 3.785 Å, c = 9.514 Å) and brookite (B-orthorhombic) (a = 5.456 Å, b = 9.182 Å, c = 5.143 Å) [3]. Only anatase and rutile structures are commonly observed in thin film form. Anatase is a low temperature metastable phase (<873 K) and it transforms to highly stable, rutile structure at high temperature (>1073 K) [4]. TiO 2 having a large band gap ranging form 3.20, 3.02 and 2.96 eV for anatase, rutile and brookite phase respectively [5]. The valance band of TiO 2 is composed of 2p orbitals of oxygen hybridized with the 3d orbitals of titanium [6]. TiO 2 thin films can be prepared by a variety of methods such as sol–gel method [7], pulsed laser deposition [8], chemical vapor deposition [9], spray pyrolysis [10] and sputtering [11 - 13]. In the above techniques, magnetron sputtering can produce highly uniform films with good adherence to the substrate. The method also offers the advantage of depositing films on large area substrate and offer mass scale deposition. 2. Experimental: 2.1 Instruments: Titanium dioxide (TiO 2 ) thin films were deposited by dc magnetron sputtering system. Deposition of thin films were done using circular titanium (Ti) target of 99.9% purity having diameter of 3 inch. ASI Carbon – Science and Technology ISSN 0974 – 0546 http://www.applied-science-innovations.com