Photoemission occurs when an electron absorbs the energy of a photon (light) and is ejected out of the material. By employing electrostatic lenses, we can focus and detect these electrons to construct an image of the sample. The photoemission intensity depends on the physical and chemical structure of the material, enabling photoemission electron microscopy (PEEM) to image materials with chemical contrast (Figure 2.).
The photoemission process can also be used for chemical analysis through x-ray photoelectron spectroscopy (XPS) from localised regions on the sample and chemical mapping though x-ray PEEM (XPEEM).
By analysing the momentum of the electrons when they leave the material, we can map the band structure of materials (Figure 3). This is a form of angle-resolved photoelectron spectroscopy (ARPES).
All of these techniques are capable with our NanoESCA III, and they provide information about the physical characteristics and chemical composition of materials at nanometer scales.
Instrument Leader: Professor Sarah Harmer
PEEM Facility Manager: Dr Benjamin Chambers