Effect of deposition time on structural, electrical and optical properties of Aluminium doped ZnO thin films by RF magnetron sputtering

Abstract

Transparent conducting aluminium doped ZnO (AZO) thin films were deposited on glass substrates by radio frequency (RF) magnetron sputtering at 200 °C substrate temperature, 150 W of power with various deposition times from 10 minutes to 90 minutes and maintaining working pressure of 2 × 10-3 mbar and 100 mm electrode distance. The structural, electrical and optical properties were studied using XRD, TEM, UV-VIS-NIR Spectrophotometer and four-point probe tester. The (002) diffraction peak of AZO thin films was obtained at Braggs angle of 34.40 which exhibited the hexagonal wurtzite structure of ZnO with c-axis orientation. Electrical resistivity of 1.9 x 10-3 Ω cm and average optical transmittance of 89.7 % in the visible region was obtained for the deposition time of 10 minutes. The optical band gap decreased from 3.48 to 3.013 eV with increase in deposition time.