Solid Liquid Analysis System
The surface science division of the material science faculty of the Technical University of Darmstadt operates a dedicated UHV system for photoemission spectroscopy (PES) experiments with synchrotron radiation as excitation at the Berlin synchrotron facility (BESSY II) located in Berlin-Adlershof. The so called SoLiAS system (solid liquid analysis system - Figure 1) is especially designed for the investigation of the solid-liquid interface and offers the possibility to deposit volatile materials on surfaces of interest and freeze them (LN2) in order to make PES or low energy electron diffraction (LEED) analysis. Furthermore, an electrochemical treatment of samples under nitrogen atmosphere is possible in a dedicated electrochemistry cell which is attached to the SOLIAS - Figure 2. To keep a high degree of flexibility it is mounted on a moveable frame to make the attachment to various beamlines possible - Figure 3. At BESSY II mainly the U49-2/PGM-2 and TGM-7 beamlines with photon energies of 10 … 120 eV and 90 … 2000 eV are used. Soft X-ray photoemission spectroscopy (SXPS) experiments with varying excitation energy are also possible. In addition to the mentioned PES experiments also X-ray absorption (XAS) experiments can be carried out. At the moment the SoLiAS system is mainly used for fundamental research on Li-batteries, organic solar cells, semiconductors for water splitting and absorber materials for thin film photovoltaics.
Figure 1. So-Li-AS
Figure 2. Electrochemistry cell.
Figure 3. So-Li-AS endstation layout
Methods
Instrument application
- Investigation of solids (amorphous, crystalline), especially semiconductor and metals
- Studying the interface and surface reactions after we-chemical treatment (e.g. chemical shift)
- Varying the information depth by tuning the excitation energy
- Measurement of the electronic properties of the surface (e.g. band line-up, valence band maximum, or work function)
- X-ray absorption measurements (total electron yield)
- Attachment of customer UHV systems for special scientific tasks (deposition or adsorption of new materials)
- Electrochemistry in combination with PES and LEED with an in-situ approach