Cathodoluminescence study of vickers indentations in magnesium oxide (MgO) single crystals

Abstract

Vickers diamond pyramid indentations made in single crystal of magnesium oxide (MgO) were examined in an environmental scanning electron microscope interfaced with an AVS-2000 spectrophotometer for luminescence. Three distinct zones around the indentations were identified to exhibit cathodoluminescence, which originated from plastically deformed regions of MgO crystals resulting from intrinsic defects, induced defects and electron interaction. The enhanced luminescence in the slipped region of MgO was identified as oxygen vacancies (F and F⁺ centres) while the persistent bands from both the un-slipped and slipped zones in the red regions of the visible spectrum were due to chromium ions. The region of the sample in contact with the indenter did not give rise to luminescence as a result of dislocation-induced plasticity.

Journal of Applied Science and Technology Vol. 10(1&2) 2005: 60-65