X-ray Photoelectron Spectroscopy (XPS) and Surface Ion Mass Spectrometry (SIMS)

We have a Kratos Axis Ultra ‘DLD’ X-ray Photoelectron Spectrometer and an ION-TOF SIMS (Surface Ion Mass Spectrometry) V based in the Kroto Research Institute.

X-ray Photoelectron Spectroscopy allows elucidation of the elemental composition of a surface (with the exception of H and He), as well as providing quantitative detailed chemical state, bonding and film thickness information. In XPS a monochromated X-ray beam is fired at the surface resulting in the ejection of electrons with binding energies characteristic of the atoms they originated from.

Secondary Ion Mass Spectrometry provides detailed information about both the elemental and molecular composition of the top 1 – 2 nm of a surface. In SIMS an ion beam is rastered over the surface. Fragmentation of the surface results in the release of charged atoms and molecules. Both positive and negatively charged species can be detected. The time-of-flight of any molecular ion reaching the detector is taken and converted into a molecular mass. Molecular mass, isotope ratios and mass sequences can be used to identify specific fragments which can then be mapped over the surface. Alternatively each species can be mapped simultaneously to identify molecular ions that are concentrated within certain regions of the sample.

The chemical and physical characteristics of surfaces have profound effects on the performance of materials and devices in a wide range of applications. The ability to characterise both the compositional and structural properties of a surface is essential in many areas such as:

  • Biotechnology
  • Medicine
  • Coatings
  • Adhesives
  • Fracture Analysis
  • Contamination
  • Tribology
  • Thin Film Characterisation

The equipment forms part of the Sheffield Surface Analysis Centre (SSAC) and is run by Experimental Officer Dr. Claire Hurley. Please contact Claire for XPS and SIMS use and further information on facilities within the SSAC including:

  • Atomic Force Microscopy
  • Ellipsometry
  • Contact Angle Goniometry


Graham Leggett

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