Gallium-doped ZnO (GZO), Pt/GZO, and GZO/Pt/GZO thin films having different total thicknesses and/or layer thicknesses were prepared and their characteristics were investigated. Effects of film total or layer thickness on the electrical and optical properties were studied. The use of a Pt layer largely reduces the electrical resistivity of room-temperature deposited GZO thin films by at least one order of magnitude. Theoretical calculations were performed to discuss the effects of the total or layer thickness on the optical transmittance. The calculated data are in a good agreement with the experimental data when an effective refractive index and an effective distinction coefficient were introduced in the calculations. The theoretical calculations also allow the prediction of layer thickness such that improved optical transmittance can be achieved. (C) 2007 Elsevier B.V. All rights reserved.