Effects of Ar Flow on the Optoelectronic Characteristics of Aluminum-Doped Zinc Oxide (AZO) Thin Films Prepared by RF Magnetron Sputtering

Transparent conductive aluminum-doped zinc oxide (ZnO: Al, AZO) thin films with different Ar flow (from 40 to 70 sccm) were prepared by using RF magnetron sputtering. Since decreasing the grain size of the AZO thin films with increased Ar flow, the grain boundary scattering and lattice defects were decreased, and caused the enhancement of mobility from 3.931 to 3.248 cm²/Vs at Ar flow of 60 sccm and substrate temperature of 70°C under sputtering power increased from 150 W to 250 W. In the transmission spectra, the absorption edge was about 350 nm and optical transmittance was about 80 - 96.5% in the visible range. The lowest resistivity of 7.53 × 10^-4 Ω-cm and highest transmittance of 96.5% was obtained at Ar flow of 60 sccm under substrate temperature of 70°C and sputtering power of 150 W. The observed property of the AZO thin films is suitable for transparent conductive electrode applications.