Search & Find
Home
ICPEES   >   Platforms   >   Platform for photoelectron spectroscopy

Platform for photoelectron spectroscopy

Platform for photoelectron spectroscopy

The laboratory of surface analysis of ICPEES is equipped with a multi-techniques platform for the surface analysis of solid materials

Photoelectron spectroscopy (XPS, UPS)

The principle is based on the measurement of the kinetic energy of electrons emitted from a solid under the impact of a photon beam of X-rays (XPS) or UV (UPS) of energy hv. Any core or valence electron having a binding energy less than hv may be ejected. The binding energy is characteristic of the atomic energy levels of different elements. The analysis depth is less than 10 nm, and the detection limit of 0.1 atom%.

With XPS it is possible to:

  • make qualitative elementary analysis (all elements are detectable, except from H and He).
  • make quantitative analysis
  • make depth distribution, using ion sputtering and angle resolved methods (1 to 50 nm)
  • retrieve information on the oxidation state of the detected elements (type of bonding, proportion oxide / metal ...).

UPS is used for the analysis of the valence band structure and the measurements of the work function of the surface.

Applications: industrial catalysts, polymers, nanomaterials, microelectronics, thin films etc.
Sample characteristics: all vacuum compatible solid materials, including nanostructured materials, powders, self-assembled monolayers etc can be analyzed.

In the laboratory, it is possible to perform treatments in a controlled atmosphere (temperature, gas pressure) in the reaction cells coupled to the UHV system. The sample is transferred to the analysis chamber after the treatment without exposure to the atmosphere. These quasi in situ experiments are of particular interest in monitoring the solid catalyst changes after different treatments.

Low energy ion scattering spectroscopy (LEIS)

Low Energy Ion Scattering Spectroscopy (LEIS) is a method of elemental analysis of the external surface, i.e. with a depth resolution of the order of an atomic layer. Its main asset is its high sensitivity to the surface, with a detection limit of about 1012 atoms / cm². The sample is bombarded by a single energy beam of ions, usually He+ or Ne+ of low kinetic energy (0.5 to 3 keV). A small portion of the incident ions which collide with the atoms of the surface are backscattered with a kinetic energy (E1) that depends on the mass of the target atom. From the measurement of E1, one can deduce the mass of the target atom M2. Quantitative analysis is possible by LES, but it is not straightforward and requires most of the time the use of standards.

Service Equipment

The laboratory has three ultrahigh vacuum instruments equipped with surface analysis techniques:


ThermoVGMultilabESCA3000: The system is equipped with a dual-anode source (Mg / Al) for XPS and conforms to the analysis of large sample series (up to 6 samples can be retained). Ion beam etching at the atomic level is possible, to create elemental depth profiles of thin films and nanoscale layers. The system is also equipped with a reactor for in situ treatment at atmospheric pressure and up to 600 °C.

 

VSW5000: two types of X-ray sources are available, a dual-anode source (Mg / Al) and Al monochromatized source for high resolution measurements. Possibility of angular measurements (φmax = 80 °). For UPS, the He I (hv= 21.2 eV) and He II (hv= 40.8 eV) resonance lines are used. An ion gun allows both to achieve concentration profiles by ion sputtering (Ar+) of the first atomic layers and to characterize the outermost surface by LEIS. For quasi in situ treatments, the system is equipped with a reactor with controlled pressure (10-4 mbar to 1 bar, equipped with an online mass spectrometer) that can reach up to 600 ° C. The application of voltages for electrochemical measurements is also possible.

ThermoVGMicrotech: The system is equipped with a dual-anode source (Mg / Al) for XPS and a UV source for UPS. The sample can be cooled to -170 ° C and heated up to 1200 ° C. Differentialy pumped mass spectrometer and gas dosing system for thermal desorption spectroscopy studies (TDS) is available. There is a source for metal deposition.

Contact

Our systems for surface analysis are accessible to academic and industrial groups. The equipments for surface analysis are located on the 1st floor of ICPEES (building R3), in laboratories 2 and 5.

Scientific responsible:

Technical responsible:

  • PAPAEFTHIMIOU Vasiliki (Project Engineer)

For information about the terms of access to the service and equipment, please contact the responsibles of the service.
PAPAEFTHIMIOU Vasiliki Mail: papaefthymiou@unistra.fr
Tel: +33 (0) 3 68 85 27 55

For information about the terms of access to the service and equipment, please contact the responsibles of the service.

For analysis request, fill out the form below and return it to the responsible of the service.

Download the form of analysis request