Surface composition
Atomic % of the elements in the top few nanometres.
Useful forCatalysts, coatings, treated surfacesSpectroscopy
XPS
X-ray Photoelectron Spectroscopy
XPS identifies the elements in the top few nanometres of a surface and their chemical states, such as oxidation state and bonding, from the energies of electrons emitted under X-rays.
1 test optionTop ~5–10 nm of the surfaceElements & chemical statesTypical turnaround 7–10 working days
XPS measurement principleIllustrative
01 / Overview
What is XPS?
X-ray Photoelectron Spectroscopy irradiates the sample with soft X-rays, usually monochromatic Al Kα, in ultra-high vacuum. Photoelectrons escape only from the top few nanometres, and a hemispherical analyser measures their kinetic energy, which gives each electron's binding energy.
Binding energies identify all elements except H and He, and small shifts reveal oxidation state and bonding, for example metal vs oxide or C–C vs C=O. Bulk methods such as XRF or EDS cannot see this surface chemistry; ion-sputter depth profiling can follow it below the surface.
02 / How it works
How it works
- 01
Sample enters vacuum
The sample is mounted on a holder and pumped down to ultra-high vacuum.
- 02
X-rays eject electrons
Soft X-rays free photoelectrons; only those from the top few nanometres escape.
- 03
Analyser sorts energies
A hemispherical analyser passes electrons of one kinetic energy at a time to the detector.
- 04
Chemical states are fitted
Peaks are placed on a binding-energy scale and fitted to give composition and chemical states.
03 / What it measures
What it measures
Oxidation & chemical states
Tell oxidation states and bonding apart from peak shifts.
Useful forMetal oxides, electrodes, catalystsSurface contamination
Detect thin residues, adsorbed layers and contaminants.
Useful forCleaning, adhesion and bonding failuresCarbon & oxygen groups
Resolve C–C, C–O and C=O components in the C 1s peak.
Useful forPolymers, graphene oxide, plasma-treated filmsDepth profile
Follow composition below the surface with ion sputtering, where available.
Useful forThin films, oxide layers, interfaces04 / Test options
Choose the XPS options you need
1 option · none added yet
05 / Sample requirements
Sample requirements
- Accepted forms
- Solid pieces, films and powders that are dry and vacuum-stable
- Size
- About 5 × 5 mm to 10 × 10 mm, under ~3 mm thick
- Powder quantity
- Around 20–50 mg
- Condition
- Must not outgas in vacuum: no liquids, wet or volatile samples
- Elements of interest
- List them so the right high-resolution scans are run
- Handle only with gloves and clean tweezers
- Pack in a clean container with the analysis face untouched
- Mark the side to analyse and list the elements of interest
- No liquids, oils, gels or wet samples
- No tape, marker ink or fingerprints on the analysis face
Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.
06 / Results & turnaround
Results & turnaround
What you receive
- Survey spectrum with detected elements
- High-resolution spectra of chosen elements
- Surface composition in atomic %
- Peak fitting of chemical states, on request
- Raw data files
- Report PDF
Turnaround & pricing
Typically 7–10 working days after samples reach the lab.
Price confirmed in your quotation, depending on user type, options and number of samples.
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