Characterization of Nanometer-Scale Structures on Ionic Crystals Produced by Electron Irradiation in Low Partial Pressures of Water Vapor
EMSL Project ID
2098
Abstract
We propose to examine nanometer-scale structures that we have formed on the surfaces of cleaved ionic crystals (notably single crystal sodium nitrate) by electron irradiation in the presence of 100 microPascal of water vapor. We have demonstrated that Coulomb doses of 2 keV electrons produces micron-scale conical structures on sodium nitrate, sodium chloride, and calcium hydrogen phosphate dihydrate by electron stimulated desorption (ESD) at elevated temperatures. We have recently observed that the emission of ESD products increases by at least an order of magnitude in the presence of low partial pressures of water vapor. These treatment also produces fine, secondary conical structures, presumably by a deposition process. (Secondary conical structures appear both on the irradiated ionic surface and on adjacent, inert surfaces.)To obtain preliminary images of these secondary conical structures, Mary Dawes has pushed the scanning electron microscope (SEM) in the College of Engineering at Washington State University to its limit. The imaging capabilities of a field emission SEM is required to adequately characterize these structures, which are of potential interest in the nanometer-scale structuring of materials. We therefore request time on the Field Emission SEM at EMSL and the services of microscopist James Young in order to characterize these structures.
Project Details
Project type
Exploratory Research
Start Date
2000-11-27
End Date
2001-03-31
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Dickinson JT, SC Langford, C Bandis, ML Dawes, and Y Kawaguchi. 2000. "Consequences of combining laser irradiation with other stimuli on laser desorption and ablation from wide bandgap insulators." Applied Surface Science 154-155:291-304.