Mg1.96−1.96xZn1.96xGeO4:Mn0.04 phosphors for electroluminescent display applications

Orthorhombic magnesium germenate (Mg2GeO4) doped with manganese was synthesized by solid-state reaction technique. A broad red emission with a peak at 653 nm was observed independent of excitation wavelength. The effect of Zn incorporation on structural and optical properties is investigated, keeping the concentration of Mn fixed at 2 at.%. XRD and DRS analysis of the samples reveal the formation of a solid solution up to x = 0.10 beyond which phase segregation occurs. Formation of a sub-band gap is observed for Mn doped samples which decreased with Zn doping. Both green and red emission is observed for Zn doped samples above x = 0.10. Red emission is attributed to the 4T1 → 6A1 transition of Mn2+ at Mg2+ site in Mg2GeO4 and green emission is from 4T1 → 6A1 transition of Mn2+ at Zn2+ site of Zn2GeO4. PLE was found to be red-shifted with Zn doping.