X-ray Photoelectron Spectroscopy

X-Ray Photoelectron Spectroscopy (XPS) is the ideal technique to use if you need a quantitative analysis of the surface (top 5-7 nanometers) of your sample. XPS can also give you information about the chemical bonding on the surface of your sample. For example, one can observe different bonding states of C in polymeric materials.

How XPS works — the sample is bombarded with an x-ray beam causing photoelectrons to be emitted from the surface. The energy of these photoelectrons is characteristic of the elemental composition of your sample.

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Instrumentation Available

Key Attributes

  • Elements detected: Li-U
  • Detection limits: 0.01 – 1% atomic (depending on sample and element)
  • Imaging: Yes
  • Lateral resolution 10 µm to 2 mm (depending on instrument)
  • Surface sensitivity: top 1 – 10 nm
  • Depth profiling: Yes, both elemental and molecular (with gas cluster ion bombardment)


  • Sensitive to differences in chemical environment
  • Very surface sensitive (top 1 – 10 nm)
  • Quantitative without standards
  • Straightforward analysis of insulating samples (polymers, plastic, glass, etc.)
  • Quantitative depth profiling on a wide range of materials


  • Detection limits ~ 0.1 at%
  • Hydrogen is not detectable
  • Poor lateral resolution ~30 µm
  • Sample must be UHV (<1e-9 torr) compatible
  • For organic bonding analysis, you must have some understanding of your sample


  • Identification of unknown discolorations, hazes and stains
  • Compositional analysis of powders and debris
  • Identification of surface contamination
  • Identification of changes in polymer functionality as a function of treatment
  • Compositional depth profiling of thin films stacks (both elemental and molecular)
  • Measurement of the oxide thickness on different samples

Additional Reading