Substrate to nozzle distance influence on the properties of zinc oxide films formed with chemical spray pyrolysis technique

In this work, the zinc oxide (ZnO) thin films have been deposited on the substrate glass via chemical spray pyrolysis technique that influence of the distance between nozzle and substrate on the optical, morphology, chemical composition and structural properties of two samples. Thicknesses of two samples were obtained around 300 (nm) via weighing method at a stable substrate temperature of 370 °C. Crystal structure was investigated by manner of an X-Ray Diffraction (XRD); it was found that two films have three peaks located at 2θ ≈ 32.698 , 34.185 and 36.185 with hkl (100), (002) and (101), respectively. XRD pattern appeared the present of hexagonal crystal structure with (002) arrangement and polycrystalline for two samples. Optical properties of ZnO thin films were contained study of transmittance spectrum in the extent of the wave length λ (200-1100) nm with using ultraviolet-visible spectrophotometer that varies between 89-92 %. The results of optical band gap was varied between 2.97 and 3.02 (eV) along with variable distance between substrate and nozzle 20 and 30 (cm) respectively. The morphology of surface zinc oxide was investigated by scanning tunneling microscopic (STM) and root mean square (rms) of the surface films was measured via STM. XRF spectral measurement confirms and indicates that elements present in the thin films.