Blue electroluminescence from ZnGa2O4:Eu powder samples

ZnGa2O4 and Europium incorporated ZnGa2O4 powder samples were prepared by solid state reaction of ZnO, Ga2O3 and Eu2O3 in stoichiometric quantities at 900 °C. The samples were subjected to AC powder electroluminescence and photoluminescence studies. Undoped ZnGa2O4 showed an electroluminescence peak with emission maximum around 525 nm, characteristic of luminescent centers like GaO6 structural units, anti-site defects and oxygen vacancies present in the lattice. Unlike this, for Europium incorporated ZnGa2O4 samples, blue light emission, characteristic of Eu2+ ions has been observed upon application of AC voltages. Europium ions also exist as separate Eu3+ containing phase in the samples as confirmed by photoluminescence studies. Electron Paramagnetic Resonance (EPR) studies confirmed the incorporation of Eu2+ at six coordinated Zn2+ site (anti-site) in ZnGa2O4 lattice.