The photon scanning tunneling microscope (PSTM) has been operated in spectroscopic mode to both image the topography and analyze stress features on a microindented, chromium-implanted sapphire surface. Light originating primarily from the evanescent field generated by an internally reflected beam, with some contribution from scattering by roughness features and radiation from fluorescence and luminescence, was coupled into the probe tip. The topographic resolution observed (∼50 nm) is appreciably finer than the diffraction limit. Stresses of 3 kbar around microindents were measured by monitoring shifts in the photoluminescence peaks. A discussion of the spectroscopic resolution obtainable with this ‘‘analytical PSTM’’ and applications are presented.

• Received 19 July 1990

DOI:https://doi.org/10.1103/PhysRevB.42.6750