Scanning Tunneling Microscopy of Metal/Polymer Interfaces

Abstract

In this short overview, we discuss the possibilities and limitations of using the still relatively new technique of scanning tunneling microscopy (STM) for surface and interface studies of organic molecules and polymers deposited on conducting substrates and vice versa, at a level aimed at nonSTM- specialists. Molecular structure of and the interaction at interfaces between metals and polymers are the subjects of intensive research activity, in which a variety of surface sensitive analytical tools are used. Studies of the electronic, chemical, morphological, and the molecular structure of surfaces and interfaces are of considerable importance in many application areas, in which metal/polymer and polymer/metal junctions are used. In addition to chemical and mechanical interfacial properties, recently invented applications of conjugated polymers (i.e., polymers which can be doped to a high electrically conducting state) also require information on the electronic structure at interfaces. In this paper we emphasize in particular problems with STM imaging of organic samples. STM images show both the surface topography and the surface electronic structure, and therefore, it is often difficult to interpret images and to determine the geometrical structure of organic molecules.