Effect Of Substrate Temperature On Nanocrystalline CeO2 Thin Films Deposited On Si Substrate By RF Magnetron Sputtering

Physics of Energy Harvesting Division, Council of Scientific and Industrial Research (CSIR) - National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012, India

Adv. Mater. Lett., 2015, 6 (5), pp 371-376

DOI: 10.5185/amlett.2015.5777

Publication Date (Web): May 05, 2015

Copyright © IAAM-VBRI Press

E-mail: kmk_srivatsa@mail.nplindia.org

Abstract

Single oriented nanocrystalline CeO₂ thin films have been deposited over Si (100) substrate by RF magnetron sputtering in the temperature range 600-700 ^oC, using CeO₂ target. X-ray diffraction pattern for the as deposited CeO₂ film at 700^oC shows the dominant (111) orientation with corresponding FWHM value of 0.378^o and the crystallite size 21.50 nm. The refractive index and the optical band gap both were found to increase from 2.35 to 2.66 and 3.25 to 3.43 eV, respectively with increasing substrate temperature. Atomic force microscopy results reveal highly smooth surface of the deposited films with surface roughness below 1.15 nm for the entire range of deposition temperatures. Further, the contact angle measurements on the as deposited CeO₂ films showed variation from 122.36 to 81.67^o with respect to the substrate temperature, transforming the wetting property from hydrophobic to hydrophilic in nature. These results indicate the possibility of producing CeO₂ films with varying properties for various device applications simply by controlling the substrate temperature.

Keywords

CeO₂ thin films, nanocrystalline, RF magnetron sputtering, ellipsometer, contact angle.