Upgrade of a Scanning Probe Microscopy Facility - LEED, Auger, and Sample Preparation

Washington State University, Pullman WA

Investigators

Abstract

With this award from the Chemistry Research Instrumentation: Multi-user (CRIF:MU) program, Professor Kerry Hipps and collaborators from Washington State University will upgrade spectroscopic instrumentation in the scanning probe microscopy facility that includes an ultra high vacuum scanning transmission microscope (UHV STM). The instrumentation will be upgraded with addition of a reverse-view grid optics for low-energy-electron diffraction (LEED) and Auger electron spectroscopy (AES), sample preparation chamber, preparation chamber pumping and gauging as well as other accessories. The award will enhance research training and education at all levels, especially in areas of study such as (a) structure and electronic properties of self-assembled systems, (b) surface defects and trap states in semiconductor nanoparticles, (c) analysis of organic nanostructures and photoconductivity studies, and (d) fundamental electronic properties of polymer/metal and bimetallic interfaces. Ultra high vacuum scanning transmission microscopy is an analysis method for the study of surfaces on an atomic scale providing images that supplement other well-known vacuum analysis techniques. Scanning electron microscopes, like the one upgraded under this award, allow chemists to probe the structure of materials with extraordinarily high spatial resolution and with additional chemical and electronic characterization capabilities. This level of detail is especially needed when probing the chemical and physical properties of nanoscale materials, where the chemical heterogeneity changes at precisely these length scales. Without this level of detail, the progress towards new kinds of nanoscale materials will be made much more slowly. The addition of the low-energy electron diffraction (LEED) capabilities will enhance the determination of the surface structure of crystalline materials by bombardment with a collimated beam of low energy electrons; the diffracted electrons are generally observed as spots on a fluorescent screen. In Auger electron spectroscopy, energetic electrons emitted from an excited atom are analyzed to provide information on surfaces. The infrastructure made available with this grant will be used in teaching and training a broad range of young scientists in important, cutting-edge, experimental methods.