Depth profiles of aggregate centers and nanodefects in LiF crystals irradiated with 34 MeV 84Kr, 56 MeV 40Ar and 12 MeV 12C ions

Abstract

Depth profiles of nanohardness and photoluminescence of F2 and F3 + centers in LiF crystals irradiated with 12 MeV 12C, 56 MeV 40Ar and 34 MeV 84Kr ions at fluences 1010–1015 ions/cm2 have been studied using laser scanning confocal microscopy, dislocation etching and nanoindentation techniques. The room temperature irradiation experiments were performed at DC-60 cyclotron (Astana, Kazakhstan). It was found that the luminescence intensity profiles of aggregate color centers at low ion fluences correlate with electronic stopping profiles. The maximum intensity of aggregate center luminescence is observed at fluence around 1013 ions/cm2 and rapidly decreases with further increase of fluence. At the highest ion fluences, the luminescence signal is registered in the end-of-range area only. The depth profiles of nanohardness and chemical etching have shown remarkable ion-induced formation of dislocations and increase of hardness which in the major part of the ion range correlate with the depth profile of electronic energy loss. An exception is the end-of-range region where strong contribution of nuclear energy loss to hardening at high fluences is observed. © 2018 Elsevier B.V.