SCANNING TUNNELING MICROSCOPY OF THIN ORGANIC FILMS ON CONDUCTING SUBSTRATES

We have tested the capability of the scanning tunneling microscope (STM) to characterize thin organic films on conducting substrates. Graphite turned out to be the favourite substrate material because of its large atomically flat regions and its typical fine structure. As a simple and well-known organic "model structure" perforated Formvar films with a thickness of 35 Å were used. The edges of holes and details in the structure of the foil could be imaged. The correspondence between measured and prepared thickness indicates that a special conduction mechanism through the film must exist. Formvar could be distinguished from graphite in fine structure and work function. We discuss the displacement of structures by the tip. A short description of the STM used is given. © 1990.