Reflection electron energy loss spectroscopy (REELS) is a technique that involves impinging an electron beam (0.5-2.5 kV) onto a solid sample. The resulting scattered electron can transfer energy to electrons in the solid through a number of processes in discrete amounts. The resulting REELS spectrum can provide electronic information such as the band gap of materials with Eg > 3 eV and defect states such as surface oxygen vacancies (SOV) that reside within the band gap.
Energy losses can also occur via differing masses of atoms that the electrons recoil from. One important element that can be detected in favorable cases is hydrogen.
Instrument & Applications
The REELS is part of our surface science cluster tool that also includes: XPS, Auger, UPS and low energy inverse photoemission spectroscopy (LEIPS) in one tool. Our REELS has energy resolution of <0.5 eV and can operate from 0.5-2.0 kV on any vacuum-compatible sample.