The comparison between cathodoluminescence and deep level transient spectroscopy is a powerful tool to analyze the defect formation in implanted materials. In this work aluminium implanted 4H-SiC p+/n diodes are studied. Different structures, implanted with different ion energy and fluencies, are analyzed in order to understand the process related effects. The comparison between the epilayer and the implanted areas shows an increase of the concentration of intrinsic defects in the implanted areas. The 4H-SiC band-edge emission decreases, increasing the aluminium ion dose, due to the enhancement of the lattice disorder, partially recovered by the post-implantation annealing.