Zinc Oxide thin films have been deposited on glass substrates using zinc acetate as starting precursor at different concentrations 0.05 - 0.3 M in steps of 0.05M by spray pyrolysis method at the constant substrate temperature of 350ºC. Lattice structure of the prepared ZnO films were characterized by X-Ray diffraction analysis (XRD). Diffraction pattern revealed hexagonal wurtzite structure with cell edges a=3.2530 Å, c=5.2092 Å and density 5.66 g/cm3 , which is almost equal to the standard values a=3.2556 Å, c=5.2070 Å and 5.6525 g/cm3 (COD No: 96-900-4180). Structural parameters such as dislocation density, lattice stress, unit cell volume, number of crystallites per unit area have been calculated and its dependency with thickness was studied. As the film thickness increases, the crystallite size also increases.Through FTIR, chemical bonds and their stretching vibrations confirmedthe metal-oxide phase formation. The optical studies confirmed that the presence of direct optical transitions and the calculated optical band gap increases from 3.18 to 3.52 eV on increasing the precursor concentrations. Scanning electron microscope images showed the formation of good quality film with regularly distributed spherical shaped grains. Roughness values of the films were attained from the Atomic force microscope images. In overall observations, precursor concentration has significant effect on film thickness which in turn modified the structural, optical and morphology properties of the prepared ZnO thin films

Structural Analysis, ZnO, precursor concentration, optical properties, Thin films