On the structure and ultraviolet emission of terbium doped zinc oxide thin films on silicon after high temperature treatment

Terbium (Tb) doped zinc oxide (ZnO) thin films were deposited on Si substrates by magnetron sputtering in an oxygen containing plasma. The Tb doping concentration was varied from 0 to 0.38 at.%. The effect of heat treatment at high temperature on the ultraviolet (UV) emission was studied along with the structure of the films. Photoluminescence (PL) spectra show that the UV intensity increases much by heat treatment and after 1000 °C annealing the doped films have stronger UV emission than that of an un-doped film. The enhanced UV emission is related to crystallinity improvements of the films. After heat treatment at 1000 °C Zn (Tb) silicates had formed. The film prepared with a Tb concentration of 0.029 at.% showed the best crystallinity and highest UV intensity. Finally, it was shown that the UV PL intensity can be increased further with TiN nanoparticle capping on the surface of the films.