^aDepartment of Physics, College of Science, Mustansiriyah University, Iraq

^bDepartment of Physics, College of Education, Mustansiriyah University, Iraq

^cDepartment of Pharmacy, Al-Manara College for Medical Science, Iraq

^dDepartment of Optics Techniques, Al-Mustaqbal University College, Babylon,

Iraq

This study uses glass substrates to create nanostructured TiO2 thin films employing Sol- Gel method. Afterwards, TiO2 films are annealed in air for two hours at (400, 450, and 500) °C. The XRD tests demonstrate that all films are tetragonal polycrystalline and have orientations equal to those described in the literature. These findings suggest that when the annealing temperature rises, grain size increases. As the annealing temperature is raised, the Full Width at Half Maximum (FWHM) reduces from 0.57° to 0.0.51°, and the dislocation density drops from 45.22 to 39.22.18 nm, respectively. AFM has examined the thin films' surface morphology. The films formed using this method have good crystalline and homogenous surfaces, according to AFM tests. With an increase in annealing temperature, thin films' average particle size, average roughness, and Root Mean Square (RMS) value all drop. The films' optical characteristics. The transmission was over 97% decreased with increasing annealing temperatures. It is found that the band gap decreases from 3.42 to 3.3 eV with increasing annealing temperature. Between 300 and 900 nm, the films' refractive indices range from 2.89 to 2.2.76. With higher annealing temperatures, the films' extinction coefficients fall.