Formation of optically-active disordered layers in (001) MgO single crystals

The formation of defective layers and their associated optical properties in (001) magnesium oxide (MgO) single crystals were examined in this study. To form defective layers, 100 keV beams with different doses (1015, 5 ?? 1015, and 1016 ions/cm2) of atomic nitrogen ions (N+) were used. Following the ion implantation, the surface roughness remained unaffected, while a structurally and chemically distinct surface layer was formed in the MgO single crystal. Spectroscopic methods indicated that defects in the layer consist of nitrogen ions and oxygen vacancies. Moreover, the resultant disordering triggered the softening of optical phonons. Upon using the magnetic resonance technique, it was observed that the F+ center created by oxygen vacancies did not contribute to this optical phenomenon.