Optical Properties of Lead Doped Titanium Oxide of Thin Films Prepared by Sol-Gel Method at Low Temperature

Abstract

The present paper reports on the structural and optical properties of undoped and 5% Pb-doped TiO 2 thin films deposited on glass and silicon substrates prepared by the sol-gel technique have been investigated. Dip-coated thin films have been examined at different annealing temperatures (400-500℃). The results shows that Pb-doped TiO 2 thin films start to crystallize at low temperature (400℃). The morphology and surface structure of the films were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) reveals a nanoporous structure of anatase and brookite with particle sizes ranging between 20 nm and 100 nm. Refractive index and porosity were calculated from the measured transmittance spectrum. SE study permits to determine the annealing temperature effect on the optical properties and the optical gap of the Pb-doped TiO 2 thin films. Photoluminescence (PL) spectrum revealed that emission increase with annealing temperature. A slight shift of transmission curves to higher wavelengths is observed for curves of Pb-doped TiO 2 thin films in comparison with those undoped, this was explained by the lowering of the band gap of TiO 2 .