Abstract
GaN epilayers were implanted with Eu to fluences of 1X10 13 Eu/cm 2 and 1X10 15 Eu/cm 2 . Post-implant thermal annealing was performed in ultra-high nitrogen pressures at temperatures up to 1450 C. For the lower fluence effective structural recovery of the crystal was observed for annealing at 1000 C while optical activation could be further improved at higher annealing temperatures. The higher fluence samples also reveal good optical activation; however, some residual implantation damage remains even for annealing at 1450 C which leads to a reduced incorporation of Eu on substitutional sites, a broadening of the Eu luminescence lines and to a strongly reduced fraction of optically active Eu ions. Possibilities for further optimization of implantation and annealing conditions are discussed.