Photoelectron spectroscopy (PES) is a workhorse technique for investigation of filled electronic states in solids. The short path length of photoelectrons excited with far UV radiation necessitates rigorous surface preparation procedures if experiments are to yield meaningful results. Much longer photoelectron path lengths are found under soft X-ray excitation and photoemission experiments conducted using this higher energy radiation are more tolerant of imperfect surface preparation.
Photoelectron spectroscopy is a speciality of the group, and we uniquely use a wide range of different types of PES techniques to understand the chemistry and physics of materials.
X-ray photoelectron spectroscopy (XPS)
Ambient pressure X-ray photoelectron spectroscopy (APXPS)
Hard X-ray photoelectron spectroscopy (HAXPES)
Angle resolved photoelectron spectroscopy (ARPES)
X-ray Photoelectron Spectroscopy
In the group we are fortunate to have a number of XPS systems with which can study and characterise a wide range of (typically, but not always!) oxide materials. The workhorse instrument in the Thermo Fisher K-Alpha+ instrument. This instrument is capable of measuring a wide range of samples, from oxides to biological specimens, and has excellent dual-beam charge compensation (ions and electrons), as well as having a large sample plate that can accommodate multiple samples. We also have a tilt holder for surface sensitivity measurements, a vacuum transfer module – to transfer samples from an inert environment (e.g. glovebox) without exposing it to air and a bias-stage to measure the work function of a material. We also have a monoatomic Ar ion source for depth profiling experiments. More details on how to access this equipment can be found here.
Ambient Pressure X-ray Photoelectron Spectroscopy
We also have an APXPS system that is capable of operating up to 30 mbar in a wide variety of gases.