Scanning tunneling microscopy and spectroscopy of thin metal films on the GaAs(110) surface

Abstract

The scanning tunneling microscope is used to study the properties of metal films with thicknesses in the range 1 -10 monolayers (ML). Results are presented for two materials—antimony and tin, on the GaAs(110) surface. The acquisition and analysis methods used in the spectroscopic measurements are described in detail. For Sb films, a layered structure is observed. Very low conductivity is found at the Fermi-level, indicating semimetallic behavior. For Sn films, a layered structure with semimetallic nature is observed below 2 ML. It is found that the existence of an adatom layer is important for layer by layer growth of the Sn overlayer. At Sn coverages above 3 ML, a structural phase transition is observed, accompanied by an electronic transition to a metallic state. © 1990, American Vacuum Society. All rights reserved.