The Optical and Structural Properties of ZnO Thin Films Deposited by the Spray Pyrolysis Technique

ZnO films were deposited by the chemical spray pyrolysis technique at the substrate temperature of 350 +/- 5 degrees C. Totally 200 cc of ZnO solution was sprayed at 5 ml/min controlled by a flowmeter. Nitrogen gas was used as the carrier gas. XRD measurement revealed the improvement of crystalline quality and grain size of the film as the polycrystalline structure (the hexagonal wurtzite structure) and 15.092 nm, respectively. An absorbance spectrum was taken to examine the optical properties, energy band gap, lattice parameters, refractive index, extinction coefficient, and dielectric function. The band gap and the energy levels of the defects of the ZnO film were calculated by the optical method as 3.20 eV and 2.40 eV. The dielectric function of the film was determined by the transmittance spectrum.