Amelioration of photocatalytic activity of ZnO thin films by Er doping

Competence of Er doped ZnO thin films as luminescent downshifter and efficient photocatalyst was investigated. ZnO thin films doped at various Er concentrations were deposited on glass substrates by spray pyrolysis and studied the effect of doping concentration on the properties of the films. Structural analysis revealed the phase purity of the films and EDX spectra analysis confirmed the presence of Er in the doped films. Optical transmission of the films was better in the visible and NIR region of the electromagnetic spectrum and energy gap decreased with Er doping due to the merging of conduction band minimum with the impurity bands newly formed in the forbidden gap by Er doping. Electrical resistivity decreased with Er doping due to the increase in carrier concentration and mobility. Er doping enhanced the visible emission in ZnO thin film and hence can possibly act as luminescent downshifter. Due to the proficiency of erbium ions to separate the photo-generated electrons and holes, Er doped ZnO thin films are more efficient in photocatalysis compared to undoped film.