High quality conductive gallium-doped zinc oxide films deposited at room temperature

Abstract Transparent and highly conducting gallium-doped zinc oxide films were successfully deposited by rf sputtering at room temperature. The lowest resistivity achieved was 2.6×10 −4 Ω cm for a thickness of 1100 nm (sheet resistance ≈1.6 Ω/sq), with a Hall mobility of 18 cm 2 /Vs and a carrier concentration of 1.3×10 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.