Hindawi Publishing Corporation Advances in Materials Science and Engineering Volume 2013, Article ID 574738, 10 pages http://dx.doi.org/10.1155/2013/574738 Research Article The Effect of Annealing on the Structural and Optical Properties of Titanium Dioxide Films Deposited by Electron Beam Assisted PVD Yaser M. Abdulraheem, 1 Sahar Ghoraishi, 2 Lidia Arockia-Thai, 2 Suji K. Zachariah, 3 and Moustafa Ghannam 1 1 Electrical Engineering Department, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait 2 Kuwait University Nanotechnology Research Facility, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait 3 Kuwait University Semiconductor Research Facility, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait Correspondence should be addressed to Yaser M. Abdulraheem; ymakuniv@gmail.com Received 8 December 2012; Revised 1 April 2013; Accepted 2 April 2013 Academic Editor: Pavel Lejcek Copyright © 2013 Yaser M. Abdulraheem et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Titanium dioxide thin ilms were deposited on crystalline silicon substrates by electron beam physical vapor deposition. he deposition was performed under vacuum ranging from 10 −5 to 10 −6 Torr without process gases, resulting in homogeneous TiO 2− layers with a thickness of around 100nm. Samples were then annealed at high temperatures ranging from 500 ∘ C to 800 ∘ C for 4 hours under nitrogen, and their structural and optical properties along with their chemical structure were characterized before and ater annealing. he chemical and structural characterization revealed a substoichiometric TiO 2− ilm with oxygen vacancies, voids, and an interface oxide layer. It was found from X-ray difraction that the deposited ilms were amorphous and crystallization to anatase phase occurred for annealed samples and was more pronounced for annealing temperatures above 700 ∘ C. he refractive index obtained through spectroscopic ellipsometry ranged between 2.09 and 2.37 in the wavelength range, 900 nm to 400 nm for the as-deposited sample, and jumped to the range between 2.23 and 2.65 for samples annealed at 800 ∘ C. he minimum surface relectance changed from around 0.6% for the as-deposited samples to 2.5% for the samples annealed at 800 ∘ C. 1. Introduction Titanium dioxide (TiO 2 ) has promising physical, chemical, and optical properties that make it an interesting material for a wide range of applications. TiO 2 is a wide bandgap semiconductor with an indirect optical bandgap ranging from 3.2 eV—for the anatase phase to 3.0 eV—for the rutile phase [1]. he refractive index of the bulk crystal TiO 2 ranges from 2.4 to 2.9 [2] which makes the material attractive for many optical applications including antirelective coatings for silicon based solar cells. Several methods have been used to deposit TiO 2 thin ilms on various substrates, including electron-beam evapo- ration [3–5], chemical vapor deposition (CVD) [6–8], pulsed laser deposition (PLD) [9], sputtering [10, 11], and sol-gel method [12–14]. he properties of deposited ilms, however, are highly dependent on the processing techniques and the deposition conditions [3, 4, 15–17]. Electron beam (e-beam) evaporation is one of the tech- niques used to deposit uniform and high quality titanium oxide coatings [2, 17] but still needs to be investigated explicitly due to its importance as a technique that can be used to produce antirelective coatings on an industrial scale for many applications, including solar cells. As-deposited, e-beam evaporated ilms are usually amorphous [4, 17]. In addition, it has been reported that such TiO 2 ilms have a degree of porosity and their refractive index is signiicantly lower than the bulk material [2, 5, 13].