Comparative Study on the Optical Properties of Eu:GaN with Tb:GaN

Sharp luminescence originating from intra-atomic 4f-4f transition from both Eu and Tb doped GaN was observed at 622 nm which can be assigned to 5 D 0 - 7 F 2 transition of Eu 3+ and at 545 nm which can be assigned to 5 D 4 - 7 F 5 transitions of Tb 3+ . However, the luminescence intensity of Eu 3+ is two orders of magnitude stronger than that of Tb 3+ though the content of the rare earth elements is almost the same. The cause of the difference in the luminescence properties was studied based on the defect-related energy transfer model, and the role of the defects observed by Fourier transform infrared (FTIR) spectra was discussed.