Mg-Induced Shift of Band Edge in ZnO:Mg Probed by the Visible Luminescence

Abstract

Mg-doped ZnO was synthesized using a co-precipitation technique. X-ray diffraction (XRD) measurements and absorption spectra show that Mg ions are doped into the lattice positions of ZnO. In the room temperature photoluminescence (PL) spectra, two emission bands, ultraviolet (UV) and visible, were observed. Either of two emissions shows a blue-shift. The visible emission band is composed of the green emission and the blue emission. The amount of blue-shift in green emission is 0.03 eV, about half of the amount of blue-shift in blue emission. Mg substitution raises and lowers conduction- and valence-band edges, respectively.