Scanning Tunneling Microscopic Studies of Surface Modified Thin Films

摘要

This paper describes the use of a scanning tunneling microscope to study the thin film of metals, alloys and semiconductor surfaces on atomic scale level. The study of the topography of a metal surface and the modified surfaces by addition of small amounts of alloying elements on atomic level is one of the crucial characteristics in order to make perfect thin films. Contributions of in situ STM studies include: atomic resolution of electrodeposited lead on graphite; imaging of modifications on metallic electrode surfaces induced by electrochemical oxidation-reduction processes; imaging of corrosion process on Al and Al-Ta alloy electrodes in NaCl solution; characterization of semiconductor-solution interfaces. These studies allowed the establishment of STM as a technique which, for some systems, yields atomic resolution of metallic surfaces in air and in solution; establishment of a mechanism for the electrochemically growth of oxide films on metal electrodes; establishment of a corresponding mechanism for the reduction of those electrochemically grown oxide films; direct monitoring of corrosion processes on a scale of A to μm; and determination of the presence of surface states and their energy position at the semiconductor-solution interfaces.