Time-of-flight photoelectron emission microscopy TOF-PEEM: first results

Spiecker H, Schmidt O, Ziethen C, et al. Time-of-flight photoelectron emission microscopy TOF-PEEM: first results. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. 1998;406(3):499-506.The time structure of the synchrotron radiation at BESSY (Berlin) is used to operate a photoemission electron microscope in a time-of-flight (TOF) mode. The electrons which are emitted from the sample surface with different energies are dispersed in a drift tube subsequent to the imaging optics. The screen of the microscope was replaced by a fast scintillator (tau = 1.4 ns) and the light is detected by an ultra fast gated intensified CCD camera (800 ps gate 1 MHz repetition rate). The resolving power in the energy domain is demonstrated and possible implications on the spatial resolution (chromatic correction) are discussed. Additionally, an improved contrast at very low emission energies is shown. The capability of the setup as an efficient microspectroscopic tool is illustrated. (C) 1998 Elsevier Science B.V. All rights reserved

Chemical microanalysis by selected-area ESCA using an electron energy filter in a photoemission microscope

Schmidt O, Ziethen C, Fecher GH, et al. Chemical microanalysis by selected-area ESCA using an electron energy filter in a photoemission microscope. In: Journal of Electron Spectroscopy and Related Phenomena. JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA. Vol 88. ELSEVIER SCIENCE BV; 1998: 1009-1014.We present a new and simple device for microspectroscopy being independent of the mode of electron-excitation. Micro-Xray photoelectron spectroscopy, electron-induced Anger-spectroscopy, as well as local energy-loss spectroscopy were used to investigate metal-adsorption on silicon. This new approach employs a non-imaging electron energy analyser attached to a new-generation photoemission electron microscope with integral microarea selector. Photoelectron microspectroscopy was performed using the direct beam of an undulator (U2 at BESSY) being monochromatised and focused by means of multilayer optics at hv = 95 eV. Similarly, local Auger-electron and EELS spectra have been taken using a simple electron gun for the excitation. The chemical compositions of inhomogenities in thin layers of indium on silicon and the local state of oxidation of a structured Pt-Co multilayer have been determined. (C) 1998 Elsevier Science B.V