Microstructure and optoelectronic properties of titanium-doped ZnO thin films prepared by magnetron sputtering

Titanium-doped zinc oxide (170) films were prepared on glass substrates by RF magnetron sputtering. The effect of Ti content on microstructure and optoelectronic properties of the films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, UV-visible spectrophotometer and four-point probe. The results show that all the films are polycrystalline and (002) oriented. The Ti content significantly affects the microstructure and optoelectronic properties of the films. The film with Ti dopant of 3 wt% has the largest grain size of 81.5 nm, the highest average visible transmittance of 88.7%, the lowest resistivity of 1.26 x 10(-3) Omega cm and the maximum figure of merit of 1.44 x 10(-2) Omega(-1). Furthermore, the optical bandgaps were determined by Tauc's law and observed to be an increasing tendency with the increment of the Ti content. (C) 2013 Elsevier B.V. All rights reserved.