The effect of gallium concentration and substrate temperature on the properties of Ga-Doped ZnO thin films sputtered from powder compacted target

Abstract

Gallium-doped zinc oxide films with an average thickness of 300 nm were grown on corning glass 1737 substrate by radio frequency (RF) magnetron sputtering using powder compacted target with Ga concentrations of 0 wt.%, 2 wt.%, and 4 wt.%. The structural, optical and electrical properties of the films were investigated. During sputtering, deposition temperature was varied from room temperature to 200°C in 50°C intervals. All films were polycrystalline, having a preferred growth orientation with thec-axis perpendicular to the substrate. By increasing Ga concentration and substrate temperature, the peak height corresponding to the (002) plane was significantly increased. Columnar structure was clearly observed in the film deposited with a Ga concentration of 4 wt.% regardless of deposition temperature. The lowest resistivity achieved was 4×10⁻³ Ωcm at a Ga concentration of 4 wt.% grown at 200°C. All doped films showed an overall transmittance in the visible spectra of above 90%.