Photoluminescence of anatase TiO₂ thin films achieved by the addition of ZnFe₂O₄

We report on the photoluminescence (PL) of anatase TiO₂ thin films caused by the addition of ZnFe₂O₄ nanoparticles prepared by the radio-frequency sputtering method. X-ray diffraction and PL analyses illustrate that there is a very strong band of PL from the anatase TiO₂ thin films caused by the addition of ZnFe₂O₄ at both room and low temperatures; the anatase TiO₂ thin films without this addition show no PL. There is a very weak band of PL from rutile TiO₂ thin films. The strong PL band for the anatase TiO₂ thin films with the addition of ZnFe₂O₄ may be due to increased localization of impurity- and defect-trapped excitons.