Effects of Thickness on the Structural and Optical Properties of Mn3O4 Nanostructure Thin Films

In this work, nanostructured Mn₃O₄ thin films at different of thickness (200, 250, 300, 350) nm were deposited on substrate made from glass by chemical spray pyrolysis technique with substrate temperature at 400 °C. However, during this process, The structural and optical properties of these films have been investigated using XRD, and UV-Visible spectroscopy. The X-ray Diffraction (XRD) results showed that all films are polycrystalline in nature with tetragonal structure and preferred orientation along (211) plane. The crystallite size is determined by Scherer's formula and W-H analyses and it is found that it decreases as the thickness increasing. The optical energy gap for allowed direct electronic transition was calculated using Tauc equation. It was found that the band gap decreases when the thickness increasing. The variables of the optical properties containing (coefficient of absorption, parts of real and imaginary for dielectric constant) and estimated as a function of the photon energy. Coefficient extinction of thin film was valued as a wavelength function. (paper)