Unusual and strong emission in visible region from Mn2+ and Y3+ doped ZnO nanocrystals

Unusual and strong emission in the visible region has been observed from Mn2+ and Y3+ doped ZnO nanocrystals prepared by a chemical route using CTAB (cetyltrimethylammonium bromide). Various state-of-the-art techniques including high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR) and photoluminescence (PL) spectroscopy have been employed to characterize the prepared nanocrystals. On the basis of experimental results we have proposed a schematic band model to explain the emission observe in visible region. It is not possible to exactly pin down the origin of visible emission yet we believe that the creation of different mid gap states by virtue of microstructure manipulation and dopants are likely to play a major role.