Nanoindentation of Si Nanocrystals in SiO2

Abstract

Nanoindentation is used to investigate the effects of mechanical deformation on systems of silicon nanocrystals (Sinc) embedded in SiO 2. The process is found to introduce non-radiative defects to the crystals which quench their luminescence in the localised region of the indent. The transformation to high-pressure metastable phases in the underlying Si substrate is characterised by Raman spectroscopy and transmission electron microscopy, with the critical load found to be between 50 and 100 mN for a spherical indenter and between 25 and 50 mN for a Berkovich indenter. The results are consistent with computer simulations of the indentation process on identical systems.