Green photoluminescence, structural and optical properties of Nd-TiO2 thin films

Thin films of pure and neodymium doped titanium oxide with various concentrations were deposited on crystalline silicon and onto glass substrates by spin coating technique. The influences of the concentration of neodymium on structural, morphological and optical properties were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), AFM microscopy, UV-Visible spectroscopy and photoluminescence spectroscopy. It was found that the obtained films are well crystallized with high density; moreover, all films exhibit high transmittance in the visible and near infra-red regions. The optical band gap was found in the range of 3.37 - 3.65 eV. The surfaces of the dense films are homogeneous with the presence of small grains at the surface. Better and strong green photoluminescence was observed for the 3% Nd doped TiO2 thin film around 520 nm and which shows a relationship with oxygen vacancies.