Atomic Force Microscopy/Scanning Tunneling Microscopy 3 (PDF)

years, however, more and more quantitative analyses have been performed by means of scanning probe microscopes.

In this overview, results will be discussed of nine cases of surface modification and quantitative analysis by scanning tunneling (STM) and scanning force microscopes (SFM, AFM). SPM has a considerable impact now on research and development in micro- and nanotechnology. Scanning force microscopes have become important tools for controlling the topography of electronic chips in the production process, and for analysis of the topography of micromechanical components. One of the most promising applications of scanning probe microscopy is in the elucidation of the fundamentals of future nanotechnology. In nanotechnology, materials science and solid state physics on an atomic scale should meet. Also studies of chemical and biological nanosystems will contribute to the fundamentals of future nanotechnology. Two aspects are of special interest: Firstly, the self-organization processes occurring in nature and secondly, the creation of nanosystems by surface modification and by manipulation of atoms, molecules or clusters, and the characterization of such artificial systems. It is worthwhile studying biological molecular systems, such as motors, sieves, and electrical conductors, to find ways of designing nanosystems for practical use. A review is presented below of the findings made in various subjects of potential interest in nanotechnology, which were studied at our laboratory over the past few years by scanning tunneling and scanning force microscopy.

MATERIALS AND METHODS

Local material deposition was performed with the UHV-STM supplied by Perkin-Elmer, which is operated by a Nanoscope III controller. The silicon surfaces were cleaned by flashing samples to 1250° C by direct current heating. The tunneling tips were produced by mechanical cutting in air of Au or A1 wires 0.25 mm thick. The materials used for SFM studies in air must be stable in air. In most cases, Au samples were used for exploratory studies to minimize the influence of the atmosphere. The samples were examined under a commercial atomic force microscope (Multimode SPM with Nanoscope IIIA controller) in the contact mode or the tapping mode of operation. In some cases, the chemical composition of surfaces was analyzed by Auger electron spectroscopy (AES).