Ga-doped ZnO thin films:: Effect of deposition temperature, dopant concentration, and vacuum-thermal treatment on the electrical, optical, structural and morphological properties

Transparent conductive Ga-doped Zn oxide (ZnO:Ga), thin films were prepared by the chemical spray technique using Zn acetate and Ga pentanedionate as precursors of Zn and Ga, respectively. The effect of the deposition temperature, T-s, dopant concentration [Ga/Zn], and a vacuum-annealing treatment on the physical properties of the ZnO:Ga thin films was analyzed. The electrical and optical properties were characterized through sheet resistance measurements, Hall effect, and optical transmittance in the UV-visible range. The structure and morphology were analyzed by XRD and SEM, respectively. A minimum electrical resistivity value, on the order of 7.4 x 10(-3) Omega cm was obtained under the optimal deposition conditions (T-s = 425 degrees C), [Ga/Zn] = 2 at.%). The crystallite size ranged from 18 to 28 nm depending on the deposition temperature. An optical transparency on the order of 80%, and roughness values between 24 and 62 nm were estimated. (c) 2006 Elsevier B.V. All rights reserved.