Photoelectron Spectroscopy Service
Description
X-ray photoelectron spectroscopy (XPS) consists of using a beam of X-rays to excite atomic core electrons, causing photoelectron emission. These photoelectrons yield information about the nature of the emitting atoms.
The great advantage of XPS is its capacity to analyse the nature and chemical state of surface atoms. No other surface composition characterisation technique comes close to XPS in terms of information utility and quality, data reliability and ease of interpretation of the results. Small changes in the position and shape of the peaks contain large amounts of information about the chemistry of material surfaces.
Lines of research
This technique has applications in multiple fields:
- Surface and interface characterisation of nanomaterials.
- Determination of surface oxide layer thickness.
- Changes in surface composition of materials due to heating.
- Surface characterisation of catalysts and studies of deactivation phenomena.
- Characterisation of hard disk surfaces and delamination problems.
- Identification of the causes of corrosion or degradation of a material.
- Adhesive failure analysis.
- Resolution of welding problems.
- Study of the encapsulation of active ingredients in nanostructures.
- Study of the degradation of medical or prosthesis materials.
- Appearance of intergranular defects in metallic alloys.
Infrastructures
Kratos Axis Ultra DLD high performance spectrophotometer, with the capacity to perform the following techniques: XPS (X-ray photoelectron spectroscopy), AES/ SEM (auger electron spectroscopy/scanning electron microscopy) and ISS (ion scattering spectroscopy).
The instrument is equipped with a camera for in situ chemical/thermal treatments, and can be used with different gases at pressures between 1 and 6 bars, in ultra-high vacuum, and at temperatures up to 1000°C. Studies can also be conducted at different depths to determine the chemical composition of areas near the surface, through sputtering with Ar+ ions (depth profiles) or by angle-resolved XPS, and samples can be analysed at temperatures between -100 and 600°C.
In addition, XPS can also be used to obtain XPS images (XPS imaging), yielding a map of chemical element distribution on the surfaces analysed and providing data on the two-dimensional uniformity of the surface studied.
Contact
11510, Campus de Puerto Real, Cádiz
ginesa.blanco@uca.es (Responsable división)
juanjose.perez@uca.es (Técnico división)
https://sccyt.uca.es