Electron correlation in the self-trapped hole and exciton in the NaCl crystal

A high resolution ionoluminescence study of defect creation and interaction

Helium ion microscopy has been used to investigate the ionoluminescence of NaCl. A 35 keV, sub-nanometer He(+) ion beam was used to generate ionoluminescence. The interaction of ionizing radiation with alkali halides leads to the formation of various crystal defects, in particular so-called color-centers. Their subsequent recombination with charge carriers leads to the emission of visible light. Broad peaks at 2.46 eV and 3.05 eV were measured. We have also investigated the dynamics of defect creation as a function of the beam scanning parameters (current and pixel spacing). The resolution and detection capabilities of ionoluminescence in helium ion microscopy are sensitive to both sample properties and scanning parameters.