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 Th doped GaN was observed at 622 nm which can be assigned to D-5(0) -F-7(2) transition of Eu3+ and at 545 urn which can be assigned to D-5(4) - F-7(5) transitions of Tb3+. However, the luminescence intensity of Eu3+ is two orders of magnitude stronger than that of Tb3+ though the content of th e rare earth elements is almost the same. The cause of the difference in th e luminescence properties was studied based on the defect-related energy tr ansfer model, and the role of the defects observed by Fourier transform inf rared (FTIR) spectra was discussed.