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Advances in Condensed Matter Physics
Volume 2013, Article ID 970976, 6 pages
Research Article

Effects of the Argon Pressure on the Optical Band Gap of Zinc Oxide Thin Films Grown by Nonreactive RF Sputtering

Materials Science Laboratory, Faculty of Engineering, Yucatan University, Avenida Industrias No Contaminantes S/N, A.P. 150, Cordemex, 97000 Mérida, Yuc, Mexico

Received 9 July 2013; Accepted 18 August 2013

Academic Editor: Chong-Xin Shan

Copyright © 2013 M. Acosta et al. This 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.


Zinc oxide (ZnO) thin films were grown by nonreactive RF sputtering at room temperature under varying argon pressures ( ). Their optical band gap was found to increase from 3.58 to 4.34 eV when the argon pressure increases from 2.67 to 10.66 Pa. After annealing at 200°C and 500°C, optical band gaps decrease considerably. The observed widening of the band gap with increasing can be understood as being a consequence of the poorer crystallinity of films grown at higher pressures. Measurements of morphological and electrical properties of these films correlate well with this picture. Our main aim is to understand the effects of on several physical properties of the films, and most importantly on its optical band gap.