0000000000000816
AUTHOR
C Ziethen
showing 5 related works from this author
Time-of-flight photoelectron emission microscopy TOF-PEEM: first results
1998
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 i…
Nanoelectron spectroscopy for chemical analysis: a novel energy filter for imaging x-ray photoemission spectroscopy
2005
An ovel instrument for imaging ESCA is described. It is based on a tandem arrangement of two hemispherical energy analysers used as an imaging energy filter. The main spherical aberration (α 2 -term) of the analyser is corrected by the antisymmetry of the tandem configuration. The kinetic energy range useable for imaging extends up to 1.6 keV; this is compatible with Mg and Al Kα laboratory x-ray sources. First experiments on the chemical surface composition of a Cu0.98Bi0.02 polycrystal, a GaAs/AlGaAs heterostructure and Ag crystallites on Si(111) have been performed using synchrotron radiation. The results reveal an energy resolutio no f190 meV and a lateral resolution (edge resolution) o…
Orbital mapping of carbon thin films by XANES-spectromicroscopy
2000
Abstract A laterally resolved micro-XANES study (X-ray absorption near edge structure) of amorphous carbon, hydrogen terminated CVD-diamond (100) and highly oriented pyrolytic graphite (HOPG) is presented. The results were obtained by means of a photoemission electron microscope. Using this technique the well-known spectral features of carbon in its different chemical states (sp 2 , sp 3 ) could be recorded. The sp 2 /sp 3 content of the films was extracted from the spectra. Images, taken at X-ray energies corresponding to maxima (π*, C–H*) of the unoccupied density of states in these spectra, map the lateral distribution of the different orbitals at the sample surface. This study revealed …
Magnetic Domain Imaging with a Photoemission Microscope
1997
ABSTRACTPhotoelectron emission microscopy (PEEM) has proven to be a versatile analytical technique in surface science. When operated with circularly polarized light in the soft x-ray regime, however, photoemission microscopy offers a unique combination of magnetic and chemical information. Exploiting the high brilliance and circular polarization available at a helical undulator beamline, the lateral resolution in the imaging of magnetic domain structures may be pushed well into the sub-micrometer range. Using a newly designed photoemission microscope we show that under these circumstances not only domains, but also domain walls can be selectively investigated. The high sensitivity of the te…
Defektanalyse von a-C- und CNx-Schichten mittels Röntgen-Photoemissions-Elektronenmikroskopie (X-PEEM)Characterization of stoichiometric defects in d…
2001
Amorphe Kohlenstoff- und Kohlenstoffnitridschichten werden vielseitig als Schutzschichten in der Industrie verwandt. Insbesondere werden in der Magnetfestplattenspeicherindustrie verschleisfeste sauerstoffundurchlassige Schutzschichten von wenigen Nanometern Dicke benotigt. Rontgen-Photoemissions-Elektronenmikroskopie (X-PEEM) stellt eine Analysetechnik zur Charakterisierung u.a. von Kohlenstoffschutzschichten dar, da sich Informationen uber die lokale Bindungsumgebung aus der Rontgenabsorptions-Nahkantenstruktur (XANES) gewinnen lassen. CVD-DLC- sowie a-C- und CNx-Schichten wurden analysiert. Fur die a-C-Schichten auf Si (100) wurde der Anteil sp2-hybridisierter Atome bestimmt und mit den …