Mapping the Electronic Surface Potential of Nanostructured Surfaces

We present a method for the quantitative determination of the surface potential landscape of nanostructured surfaces based on the local analysis of the lowest field emission resonances by scanning tunneling spectroscopy. The method has a lateral resolution of similar to 1 nm and is applied to elucidate the site-specific adsorption properties of the strain relief pattern formed by two monolayers of Ag on Pt(111). For the example of C(60) fullerenes, we show that the surface potential difference of up to 0.35 eV is responsible for the site-selective immobilization on the strain relief pattern.