Europium was implanted into GaN through a 10 nm thick epitaxially grown AlN layer that protects the GaN surface during the implantation and also serves as a capping layer during the subsequent furnace annealing. Employing this AlN layer prevents the formation of an amorphous surface layer during the implantation. Furthermore, no dissociation of the crystal was observed by Rutherford backscattering and channeling measurements for annealing temperatures up to 1300degreesC. Remarkably, the intensity of the Eu related luminescence, as measured by cathodoluminescence at room temperature, increases by one order of magnitude within the studied annealing range between 1100 and 1300degreesC. (C) 2004 American Institute of Physics.