MICROSTRUCTURAL, ELECTRICAL AND OPTICAL PROPERTIES OF DC REACTIVE MAGNETRON SPUTTERED ZINC ALUMINUM OXIDE THIN FILMS FOR OPTOELECTRONIC DEVICES

Zinc Aluminum Oxide (ZAO) thin films have been deposited on glass substrates by DC reactive magnetron sputtering technique. The structural, electrical and optical properties of ZAO thin films deposited with various substrate temperatures were investigated. XRD patterns exhibits ZAO thin films had a diffraction peak corresponding to (0 0 2) preferred orientation with the c-axis perpendicular to the substrate surface. The preferred orientation is due to the lowest surface free energy for (0 0 2) plane. The minimum resistivity of 5.14 X10-4 Omega.cm is obtained for the thin film deposited at substrate temperature of 300 degrees C. Optical absorption edge of ZAO thin films has a significant blue shift to the region of higher photon energy. The average transmission of ZAO films in the visible range is > 80%. The optical direct band gap values of ZAO films increased with increasing substrate temperature and this may be attributed to Burstein-Moss shift.