Transparent and highly conducting gallium-doped zinc oxide films were successfully deposited by if sputtering at room temperature. The lowest resistivity achieved was 2.6 X 10(-4) Omega cm for a thickness of 1100 nm (sheet resistance approximate to 1.6 Omega /sq), with a Hall mobility of 18 cm(2)/Vs and a carrier concentration of 1.3 X 10(21) cm(-3). The films are polycrystalline with a hexagonal structure and a strongly preferred orientation along the c-axis. A linear dependence between the mobility and the crystallite size was obtained. The films present a transmittance in the visible spectra between 80 and 90% and a refractive index of approximately 2. which is very close to the value reported for bulk material. (C) 2003 Elsevier B.V. All rights reserved.