Effects of substrate temperature on the properties of heavy Ga-doped ZnO transparent conductive film by RF magnetron sputtering

Abstract

Gallium-doped zinc oxide (GZO) transparent conductive thin films were deposited on glass substrate by RF magnetron sputtering using a ceramic ZnO target with 10 wt. % Ga2O3 doped. The effects of substrate temperature on structural, electrical and optical properties of the films were investigated. X-ray diffraction (XRD) measurements indicated that GZO films were polycrystalline and strongly c-axis oriented. The surface roughness evaluated in terms of RRMS measured by atomic force microscope (AFM) was 1.8 nm for the smoothest surface obtained at 250 °C. The electrical resistivity decreases with increasing substrate temperature and the lowest resistivity obtained was 5.8×10-4 Ω·cm at 350 °C. The average transmittance in the visible region was over 90%. The carrier concentration increased with substrate temperature increasing, and the highest mobility value was 22.1 cm2v-1·s-1.