Optical and structural characterization of blue-emitting Mg2+- and Zn2+-doped GaN nanoparticles

We show blue photoluminescence (∼425 nm) from both Mg2+- and Zn2+-doped GaN nanoparticles. The effect of the doping concentration of these ions on the structural and optical properties was systematically studied using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL) and Raman spectroscopy. Starting from nitrate salts of gallium, zinc and magnesium we observed the formation of Mg2+- and Zn2+-doped Ga2O3 accompanied by Ga2O3. During the thermal cycle for the formation of GaN some of the zinc evaporates because of its relatively low boiling point. The PL intensity is proportional to the final concentration of the dopant ion in the final product and a weaker band is observable at a higher energy corresponding to the undoped GaN. Raman spectroscopic analysis confirms the distortion of the GaN lattice due to the incorporation of Mg2+ and Zn2+.