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Spectroscopy of surfaces

Surface spectroscopy serves to get information about the chemical nature of sample surfaces or surface near regions. For those a spectrometer working under ultra high vacuum conditions is used. The X-ray photoelectron spectrometer allows to analyse the elemental surface composition quantitatively. Different binding states of the detected elements may be distinguished. Angle resolved photoelectron spectroscopy is a non-destructive method to investigate the distribution of elements or functional groups in the depth of the sample surface.
The knowledge of the chemical surface composition and the kind of functional surface groups is the fundament to evaluate surface reactivity and apply chemical and physico-chemical methods to modify the solid surface.

Fields of work

  • Photoelectron spectroscopy (XPS, ESCA) to quantitatively analyze elements and functional surface groups more...        'Text'            'Lecture XPS'
  • Quantitative detection of adsorbed surface active species (surfactants, drugs, latices, proteins, cells)
  • Chemisorption of reactive polymers at inorganic and polymer surfaces
  • Orientation analysis of molecules or functional groups by angle-resolved XPS measurements

  • Time-of-Flight Secondary Ion Mass Spectrometrie (SIMS)  'Lecture SIMS'

Coworkers

Equipment

  • ESCAlab 220i (Vacuum Generator, UK) equipped with two X-ray sources for monochromatic A1 K alpha and non-monochromatic Mg K alpha X-ray irradiation, and a He capillary discharge light source
  • Photoelectron spectrometer AXIS ULTRA (Kratos Analytical, UK) equipped with a X-ray source for non-monochromatic  Mg K alpha X-ray irradiation and monochromized X-ray sources for A1 K alpha and Ag L alpha X-ray irradiation (see picture below). Samples on stages and under investigation can be heated (up to 600°C) or cooled (up to -195°C). Further features are small-spot XPS analysis (smallest field of view 27 µm), imaging XPS (lateral resolution ca. 10 µm)
  • Quadrupole mass spectrometer QME 200 for rest gas analysis
  • Fracture stage for sample preparation under ultra high vacuum conditions

Publications