THE SEARCH FOR RESIDUAL RESISTIVITY DIPOLES BY SCANNING TUNNELING POTENTIOMETRY

A review is given of the application of scanning tunneling potentiomet ry (STP) to the study of potential variations due to scattering from l ocalized centers. Landauer has theoretically investigated such scatter ing in the ballistic regime where the electronic mean free path exceed s the size of the scattering centers. Landauer's analysis predicts the formation of a residual resistivity dipole (RRD) in the electrochemic al potential. The dipole moment of the RRD is larger than that expecte d from conventional diffusive scattering theory. We have applied STP t o search for RRDs in the vicinity of surface voids in thin bismuth fil ms. Although these experiments were carried out at room temperature ba llistic, transport effect became apparent, but diffusive scattering (p honon scattering) still accounted for a significant part of the observ ed dipoles. This review also includes a discussion of scattering from other types of defects such as grain boundaries and misfit dislocation s. (C) 1998 Academic Press Limited.