Structural, optical and photoluminescence properties of Al doped ZnO thin films by spray pyrolysis

Undoped and aluminium doped zinc oxide thin films were deposited by the spray pyrolysis technique onto the glass substrates at 450°C using a precursor solution consisting of zinc chloride (AlCl₃). The structural, optical and photoluminescence properties of these films were investigated as a function of Al concentration (0, 3, 5, 7 and 10 at %). The films showed a hexagonal wurtzite structure and high preferential orientation in the (0 0 2) crystallographic direction. The optical transmittance spectra showed transmittance higher than 80% in the visible region. The Al doping has improved the crystallinity and the luminescence in the visible region.