Measurements of photon intensity map for metal particles by scanning tunneling microscopy

We have measured maps of the photon intensity emitted from gold metal particles in scanning tunneling microscopy (STM) of metal films in ultra high vacuum. The photon images are obtained with a spatial resolution in a nanometer scale. The photon intensity is recorded simultaneously with the measurements of a topography image of the film by STM. We have measured photon images for various morphologies of the film. The observed photon maps are well correlated with the morphology. The photon maps for the dense aggregation of small particles show similar contrasting particles to those on the corresponding morphology. The photon intensity for the rough surface is influenced by the surface geometry of the tip and the particles, and the contrast of the photon map is modified from the morphology. We have observed that the photon intensity is dependent on the material and the grain of the material. The effect of the asymmetry of the tip shape on the photon map is found.