Scanning photoelectron microscope with a zone plate generated microprobe

Abstract

We describe instrumentation of a scanning photoelectron microscope (SPEM), which we are presently developing and commissioning at the X1A beamline of the National Synchrotron Light Source (NSLS). This instrument is designed to use the soft-X-ray undulator (SXU) at the NSLS as a high-brightness source to illuminate a Fresnel zone plate, thus forming a finely focused probe, ≤ 0.2 μm in size, upon the specimen surface. A grating monochromator selects the photon energy in the 400-800 eV range with an energy resolution better than 1 eV. The expected flux in the focus is in the range 5 × 107-109 photons s-1. A single pass cylindrical mirror analyzer (CMA) is used to record photoemission spectra, or to form an image within a fixed electron energy bandwidth as the specimen is mechanically scanned. As a first test, a 1000-mesh Au grid was successfully imaged with Au 4f primary photoelectrons, achieving a resolution of about 1 μm. © 1990.