Catarino, N.Nogales Díaz, EmilioFranco, N.Darakchieva, V.Miranda, S.M.C.Méndez Martín, María BianchiAlves, E.Marques, J.F.Lorenz, K.2023-06-202023-06-202012-030295-507510.1209/0295-5075/97/68004https://hdl.handle.net/20.500.14352/44054Copyright c EPLA, 2012. Financial support by FCT Portugal (Ciência 2007, PTDC/CTM/100756/2008) and through the bilateral Spanish-Portuguese project HP-2008-0071 is gratefully acknowledged.The implantation damage build-up and optical activation of a-plane and c-plane GaN epitaxial films were compared upon 300 keV Eu implantation at room temperature. The implantation defects cause an expansion of the lattice normal to the surface, i.e. along the a-direction in a-plane and along the c-direction in c-plane GaN. The defect profile is bimodal with a pronounced surface damage peak and a second damage peak deeper in the bulk of the samples in both cases. For both surface orientations, the bulk damage saturates for high fluences. Interestingly, the saturation level for a-plane GaN is nearly three times lower than that for c-plane material suggesting very efficient dynamic annealing and strong resistance to radiation. a-plane GaN also shows superior damage recovery during post-implant annealing compared to c-plane GaN. For the lowest fluence, damage in a-plane GaN was fully removed and strong Eu-related red luminescence is observed. Although some residual damage remained after annealing for higher fluences as well as in all c-plane samples, optical activation was achieved in all samples revealing the red emission lines due to the ^5Do -> ^7F_2transition in the Eu_3+ ion. The presented results demonstrate a great promise for the use of ion beam processing for a-plane GaN based electronic devices as well as for the development of radiation tolerant electronics.engjournal articlehttp://iopscience.iop.org/0295-5075/97/6/68004http://iopscience.iop.orgopen access538.9Radiation-DamageCrystalsNonpolarFísica de materiales