Synthesis and enhanced blue emission of Eu ²⁺-doped GaN/SiO ₂ nanocomposites by addition of SiO ₂ nanoparticles

The enhanced blue emission of Eu ²⁺-doped GaN/SiO ₂ nanocomposites prepared through the nitridation process in an Ar environment containing 5% H ₂ and NH ₃ gas at 1000°C was investigated as a function of the amount of SiO ₂ nanoparticles added. The X-ray diffraction patterns indicate that the Eu ²⁺-doped GaN/SiO ₂ nanocomposites consisted of a powder mixture of Eu ²⁺-doped GaN and amorphous SiO ₂ particles. The back-scattering electron image and mapping data indicate that the SiO ₂ nanoparticles enclose the Eu ²⁺-doped GaN nanoparticles to form aggregates. The red shifted peaks for the Ga-N bonds observed in the Fourier transform infrared spectra were attributed to the formation of GaO _xN _y and GaN intermediates. Strong emission and shoulder peaks of the Eu ²⁺-doped GaN/SiO ₂ nanocomposites were observed at around 470 nm and 450 nm upon the addition of SiO ₂, respectively. The Eu ²⁺-doped GaN/SiO ₂ nanocomposites showed the highest blue emission intensity at 0.15 mol% of SiO ₂ nanoparticles.