0000000000352222
AUTHOR
B. Krömker
Nanoelectron spectroscopy for chemical analysis: a novel energy filter for imaging x-ray photoemission spectroscopy
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…
NanoESCA: imaging UPS and XPS with high energy resolution
Abstract A novel imaging electron spectrometer has been used for laterally resolved ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) in the soft X-ray range. The instrument is based on a high-resolution emission microscope optics using a cathode lens and an imaging dispersive analyser. The analyser is corrected for the leading aberration term ( α 2 -term) by means of two hemispherical analysers in antisymmetric configuration with an appropriate transfer lens. Small-area spectra as well as energy-filtered images have been taken in the soft X-ray range for a meteorite sample and in the range of the d-band of a Cu polycrystal. An energy resolution of 106 …
Quantitative microscopy of magnetic domains in Fe(100) by core-level x-ray photoelectron spectroscopy
We present an experimental technique for imaging of magnetic domain patterns based on element-specific core-level photoemission using polarized soft-x-ray radiation. It is applied to the measurement of domain patterns at the Fe(100) surface and at the surface of polycrystalline Fe. Different from well established imaging techniques that use a photoemission electron microscope to measure the secondary electron intensity at the Fe absorption threshold, we have investigated the photoemission intensity contrast on the the Fe $2{p}_{3∕2}$ core level using circularly polarized x-ray light. The linear and circular dichroism characteristics of the identical domain pattern are extracted by linear co…
Trace element analysis in pre-solar stardust grains via full-field imaging XPS (Nano-ESCA)
An acid-resistant, SiC-rich, residue from the Murchison meteorite was investigated by means of a novel imaging XPS instrument. The micrometer-sized grains were deposited on a Si wafer from an aqueous suspension. Energy filtered ESCA images have been taken in the kinetic energy range from the threshold up to about 400 eV for various photon energies. A lateral resolution of the order of 120 nm along with a high energy resolution in the range of 100 meV provides the basis for chemical trace element analysis with maximum sensitivity. Apart from major (Si, C) and minor (N, Mg, Al, Fe) elements, the energy filtered images and local microspectra revealed the presence of a variety of heavy trace el…