Rapid thermal annealing of rare earth implanted ZnO epitaxial layers

S. M. C. Miranda, M. Peres, T. Monteiro, E. Alves, H. D. Sun, T. Geruschke, R. Vianden and K. Lorenz

Optical Materials, Proceedings of the EMRS Spring meeting 2010 Symposium K, Article in press

DOI Link: 10.1016/j.optmat.2010.10.009

Abstract:

Zinc oxide epilayers grown by metal organic vapour phase epitaxy on (0 0 0 1) sapphire substrates were doped with Praseodymium and Europium by ion implantation. The as-implanted samples were either annealed in air for 20 min in a tube furnace or rapid thermal annealing (RTA) was performed, for 2 min, in a nitrogen atmosphere. The samples were characterized by Rutherford Backscattering Spectrometry/Channelling and photoluminescence. The presented results indicate that in the as-implanted samples the majority of the rare earth (RE) ions are incorporated into substitutional Zn-sites. Furnace annealing at 1000 °C recovers the crystal quality of the samples but leads to an out-diffusion of the RE. RTA suppresses diffusion but lattice damage is not fully recovered at 1000 °C. More importantly, during RTA the RE ions are driven from the substitutional site and are now found mainly on random interstitial sites and no optical activation could be achieved.