Cu, Mn doping effect to optical behavior and electronic structure of ZnO ceramic Original Research Article

ZnO and Mn- or Cu-doped ZnO ceramics have been investigated using photoluminescence (PL) spectra and through X-ray photoelectron spectroscopy (XPS). The PL spectra show that the band gap is approximately 3.19 eV, 3.17 eV, and 3.01 eV for ZnO, Zn0.925Mn0.075O, and Zn0.99Cu0.01O ceramic, respectively. The XPS experimental results reveal that the Cu ion is Cu2+ and the Mn ion is Mn3+ in these ceramics. A broad impurity (defect) band has been observed in the band gap; its maximum intensity is at approximately 0.83 eV, 0.30 eV, and −0.02 eV for ZnO, Zn0.99Cu0.01O, and Zn0.925Mn0.075O, respectively. Moreover, the substitution of Cu and Mn for zinc ions induces a shift in the top of the valence band. Based on this experiment study, we conclude that the visible PL radiation of ZnO originates from the transition between the impurity (defect) band and the valence band, and that ultraviolet emission results from the transition between the conduction band and the valence band.