Optical and structural studies in Eu-implanted AlN films

Eu ions were incorporated into AlN thin films using ion implantation, and the influence of the postimplant annealing ambient on structural and optical properties was investigated. Eu is incorporated into lattice sites which are slightly displaced from the substitutional Al sites. When compared with the asimplanted sample the near-substitutional ion fraction is reduced due to the thermal annealing in different atmospheres. The AlN crystal quality does not change with different annealing conditions, but sensitive defect-related emission bands are developed under different annealing temperatures. Eu 3+ optical activation is detected for all the annealed samples. No spectral changes are observed for the shape of the intra4f 6 5 D0 ! 7 F2 transition, suggesting that a similar site symmetry is preserved even when a slight displacement from the substitutitional site of the Eu 3+ ions occurs. The role of the annealing conditions on the spectral position and thermal quenching of the 5 D0 ! 7 F2 transition is discussed.