Optical and microstructural properties of sol-gel spin coated MgAl₂O₄ thin films

Magnesium aluminum oxide (MgAl₂O₄) thin films were prepared by sol-gel spin coating method. The as-prepared films were calcined at 500oC for 12, 18 and 24 hours. The calcinated films were exhibited with polycrystalline in nature cubic structure. (311), (400) and (440) diffracted lines were preferentially oriented in MgAl₂O₄ thin films. The crystallite size, lattice constant, microstrain, dislocation density, stacking fault probability and number of crystallites were calculated to study the indeed microstructural analysis of MgAl₂O₄. Tauc’s plots were used to estimate the optical band gap energy and were observed in the range of 3.11-3.33 eV for 12-24 hours calcined MgAl₂O₄ thin films, respectively. The optical dispersion parameters were calculated using Spitzer-Fan model. Also, other refractive indices and complex dielectric constants were intensely discussed. The morphological studies were depicted the surface nature of the films. The electrical conductivity and activation energy values were discussed with calcinating time variations.