Structural and optical properties of GaN:Eu nanoparticles synthesized by simple ammonification method

摘要

GaN:Eu nanoparticles have been synthesized by simple ammonification of a mixture of Ga(NO_3)_3 and Eu(NO_3)_3. TEM images showed that the sizes of the particles were almost uniform, and the average grain sizes of the samples prepared at 850,950, and 1050 °C were evaluated as 4.2 nm, 16.8nm, and 24.3 nm, respectively. Except for conventional GaN Raman shifts, two extra peaks at 255 and 419 cm~(-1) observed in the Raman spectra could be attributed to the phonons activated by surface disorders or finite-size effects and vibration mode of N-rich octahedral Ga-N6 bonds, respectively. From PL spectra, five characteristic peaks of Eu~(3+) ions were clearly observed: ~5D_1 - > ~7F_1 (543 nm), ~5D_0 - > ~7F_1 (592 nm), ~5D_0 - > ~7F_2 (614 nm), ~5D_0 - > ~7F_3 (652 nm), ~5D_0 - > ~7F_4 (697 nm). Besides, the influences of the synthesized temperature and Eu~(3+) ion concentration on the PL behaviors were also studied.