Enhanced dynamic annealing and optical activation of Eu implanted a-plane GaN N. Catarino, E. Nogales, N. Franco, V. Darakchieva, S. M. C. Miranda, B. Méndez, E. Alves, J. G. Marques and K. Lorenz EPL, 97 6 (2012) 68004 Published online: 20 March 2012 DOI: 10.1209/0295-5075/97/68004