Synthesis and Characterization of Nano- Structure TiO2 Thin Film Prepared by Sol-Gel Spin Coating Method

摘要

Titanium dioxide thin films have been synthesized by sol-gel spin coating technique on glass substrate. The prepared thin films have been submitted to different annealing temperature ranging from 300 upto 500 oC. The effects of annealing temperatures on the structural and optical properties of thin films were investigated. The films were characterized by different techniques: X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The characterization studies revealed that the films are crystallized into nano-structured anatase phase. The crystallite sizes obtained from XRD annealed at 300, 400 and 500 oC are found to be about 159.34, 76.95 and 17.61 nm respectively. The crystallite size of TiO2 thin films decreased with increasing annealing temperature. The mentioned data were confirmed by TEM, which revealed the presence of TiO2 nano-particle of about (~3-4 nm). The optical measurement showed the direct band gap at 4.27, 4.28 and 4.37 eV for 300, 400 and 500 oC, respectively. The TiO2 thin films have higher transparency in the visible range at 500 oC. SEM image of films annealed showed nano-crystalline structure of TiO2 particles and they are approximately in spherical forms.