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METHODS

X-ray Photoelectron Spectroscopy (XPS)

In an X-ray photoelectron spectrometer, electrons are excited by X-rays so strongly that they leave their atoms and ultimately exit the sample surface (XPS-Flyer.pdf). The energy of these photoelectrons is measured and used to calculate their binding energy, enabling a qualitative and quantitative determination of the chemical composition in the top 5 to 10 nm of the surface.

With this technique, all elements except hydrogen and helium can be detected, and their binding states can be analysed. The detection limit is approximately 0.1 at%, corresponding to about 1 ng/cm² on the sample surface.

Our spectrometer is suitable for all standard analyses and is particularly notable for its ability to investigate micrometre-sized structures from 5 µm.

According to which standards do we test?

Whenever possible, we carry out our testing services in accordance with or based on these international standards:

  • ISO 14606
  • ISO 15472
  • ISO 19318
  • ISO 20903
  • ASTM E1078

For which material tests do we use this method?

We use our XPS for quantitative surface analysis of all elements (except H and He) and oxidation states. Examples of applications are

  • Trace analysis: Identification of chromium-6 / Cr(VI)
  • Determination of the surface composition of medical devices (organic as well as inorganic substances), as recommended in ISO 10993-18 and ASTM F2847.

What experimental options are available?

In addition to the standard analysis, there are various other options:

What should you know about this method?

What are suitable samples for this method?

We can analyze all vacuum-resistant metallic (including magnetic) and non-metallic solids and powders.

What do I need to bear in mind with the samples?
Specimen specifications:
  • Sample size is max. 80 x 80 x 10 mm or 40 x 40 x 20 mm. Larger samples can be cut to smaller samples.
  • Cleanly packed, we recommend in aluminum foil
How many measuring points should be analyzed?

We generally recommend 3 measurements, e.g. 3 measurements on one spot and 3 next to it as a reference. This ensures that the results are statistically relevant.

Is the method accredited?

Yes, we are the only laboratory in Switzerland to offer XPS analyses accredited to ISO/IEC 17025.

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Who is your contact person?

Roman Heuberger
Dr. sc. ETH Zurich, Certified Materials Engineer ETH
Head of Materials Testing and Consulting
+41 32 644 2022