The spatial resolution of a near-field optical spectroscopy system in the R -line photoluminescence mode has been evaluated to assess the resolution with which stress measurements can be made by piezospectroscopy. The effect of the probe tip-sample distance as well as the aperture size of the near-field probe on the luminescence R -line intensity was obtained. The luminescence intensity was found to increase linearly with the third power of the aperture size, whereas the lateral spatial resolution was proportional to the aperture size. These findings are consistent with a simple model for the electric dipole moment interaction between the tip and the sample. The minimum lateral spatial resolution was found to be 160 nm using the smallest available aperture size of ∼100 nm. Images of the stress distribution in a polycrystalline alumina are presented, showing variations at this scale.
ASJC Scopus subject areas
- Physics and Astronomy(all)