Microstructure, optical and electrical properties of gallium-doped ZnO films prepared by sol-gel method

Gallium doped zinc oxide (GZO) films were deposited by dip-coating technique with different viscosity sols. The effect of the sols viscosity on the microstructure, optical and electrical properties of the GZO films was investigated. The GZO films were polycrystalline with hexagonal structure. The root mean square roughness (Rms) of the GZO films increased with the increase of the sols' viscosity. When the viscosity reached 2.7 cps, GZO films with the resistivity of 1.9 × 10−2 Ω cm and the hall mobility of 32 cm2 V−1 s−1 were obtained. Several crack and mountain-like structure appeared on the surface of GZO films fabricated with 3.0 cps sol. The transmittance of all the GZO films was higher than 80% in visible range except for GZO films prepared with 3.0 cps sol.