Seminars Archive

Spatially Resolved X-Ray PhotoElectron Spectroscopy Investigation@ESCAmicroscopy – Solutions Toward Near Ambient Pressure XPS Microscopy

Abstract
Scanning PhotoEmission Microscopes (SPEM) use a direct approach to chemically characterize surfaces and interfaces at the submicron scale i.e. the use of a small focused x-ray photon probe to illuminate the sample. The focusing of the x-ray beam is performed by using a Zone Plate and the sample surface is mapped by scanning the sample with respect to the focused beam. At the SPEM of the Elettra synchrotron light source, hosted at the ESCAmicroscopy beamline, the x-ray beam can be downsized to a diameter of 120 nm which allows an effective imaging resolution of less than 50 nm. The overall energy resolution is better than 200 meV. Some recent achievements in the chemical, physical and electronic characterization of nano- and micro-structured materials, such as carbon nanotubes and semiconducting nanowires, will be presented providing an overview of the capabilities of this powerful technique. Other examples will illustrate the characterization of the surfaces of Solid Oxide Fuel Cells under operating conditions showing how dynamic phenomena such as mass transport can be monitored by the SPEM. Only recently the development of electron energy analyzer with differentially pumped lens systems allowed to perform in situ XPS measurements up to few mbar (near ambient pressure). Feasibility test and first results of innovative and cheap solutions developed at Escamicroscopy for photoemission microscopes, which can be potentially used to address the “pressure gap” problem in any XPS system, will be presented and discussed.