Structural, electrical and optical properties of multilayer TiO2 thin films deposited by sol–gel spin coating

•Multilayer thin films of TiO2 have deposited on glass substrate by using Sol – gel spin coating.•The crystallinity and electrical properties of films have improved as compared to Single layer of TiO2.•The optical band gap energies of 1, 2, 3 and 4 layers of TiO2 thin films are 3.65, 3.60, 3.59 and 3.40eV respectively. This decrease in band gap is due to increase in grain size of TiO2 layers. Also, some sub-bands were formed due to defect levels in the forbidden band of TiO2 thereby reducing the band-gap energy. Titanium dioxide (TiO2) multilayer thin films having 1, 2, 3 and 4 layers have been deposited on glass substrate by using “sol–gel spin coating” technique. TiO2 has anatase crystal structure and the grain size is increased when the coating layers have been increased, according to XRD results. Four point probe measures the electrical properties showed that the average resistivity is decreased with increasing the stacked layers. “Optical properties” of the films were measured by “UV–Vis spectroscopy” which showed the high transmittance in the visible region. The “optical band gap energies” of 1, 2, 3 and 4 layers of TiO2 films were 3.65, 3.60, 3.59 and 3.40eV, respectively. These properties showed that the multilayer films of TiO2 can be enhanced the properties of optoelectronic devices.