A comparative study of coldly- and warmly-condensed Ag films by scanning tunneling microscopy

Using scanning tunneling microscopy with a subnanometer lateral resolution we have studied silver films condensed at ∼ 90 K and at room temperature (RT). The coldly-condensed films are known to show the surface enhanced Raman effect, while the RT condensed films do not. We observe in real space that the coldly-condensed films exhibit nearly flat portions (average size 130 Å) separated by deep trenches of less than 30 Å width. In contrast, the RT condensed films do not exhibit trenches and their surface topography may be described in terms of a "rolling surface" with low-angle bounderies. © 1985.