Lawrence Berkeley National Laboratory

We report on the temperature dependent cross-relaxation process of Tm implanted in AlN. Investigated AlN samples were grown on sapphire by molecular beam epitaxy, doped by implantation with Tm ions with 150 keV maximum implantation energy with a dose of 1?1016 At/cm2 (the peak concentration of Tm3+ ions was 3.4?1021 At/cm3). Samples were thermally annealed at 1050?C in ammonia at atmospheric pressure to remove implantation induced defects. The low temperature (12 K) 'blue' part (460-489 nm) of CL spectrum of Tm-doped AlN shows multiple transition lines originating from 3P, 1I, 1D and 1G manifolds. It was observed that the shape of the CL spectrum changes radically when temperature increases leaving dominant two groups of lines centered at 463 nm (1D2?3F4) and 466 nm (3P1?3F3,2) at 300 K. These changes resulted in one order of magnitude increase of blue emission intensity with respect to low temperature emission. The experimental data are analyzed using the thermally dependent cross-relaxations processes between 1I6, 1G4 and 1D2, 3P1 terms.