Synergy between electronic and nuclear energy losses for color center creation in AlN

Optical absorption induced by swift heavy-ion irradiations in AlN was studied in situ at 15 K. Detailed analysis of the influence of both electronic and nuclear stopping power indicates that the electronic energy loss does not create the point defects inducing the observed absorption band at 4.7 eV. Elastic displacements are required. Nevertheless, an unexpected non-linear enhancement is induced by the electronic energy loss. The intensity of the synergy between electronic excitations and elastic collisions increases markedly with the electronic stopping power. For the heaviest projectiles, the enhancement of the color center creation yield amounts to two orders of magnitude.