Selenium #
Orbitals and Energies #
Note – these are listed in BINDING ENERGY
Se 3d ≈ 55 eV
Se 3s ≈ 232 eV
Ce 3p ≈ 162 eV
Common Overlaps for Se 3d #
Li 1s – Ir 4f – Ag 4p – Mo 4s – Er 5s – Co 3p – Th 6s – Fr 5d – Lu 5s – Hg 5p – Os 5p – Pd 4p – Fe 3p – Sc 3s – Au 5p – Mg 2p – Tm 5s – Yb 5s
Theory and Background #
Selenium is typically analysed by the 3d region, which is at very low binding energy, and as such the analysis will comprise of a relatively deep slice of the material surface (compared to elements like oxygen etc).
In layered materials (e.g. GaSe photovoltaics) it may be prudent to compare peaks of a similar binding energy (e.g. Ga 3p instead of Ga 2p), or correct for the attenuation if IMFP calculation is possible.
Experimental Advice #
Selenium has a very large auger region, spanning around 100 – 500 eV when using an Al X-ray source. Recording peaks in this region when Se is present may require wider than typical analysis regions.
Data Analysis Guidance #
Background creation may be tricky in the 100-500 eV region, so if possible record a ‘blank’ reference (e.g. Se(0) to get an appreciation for how the Se LMM behaves in the area of interest.
C 1s is a notable example of a region with significant Auger intensity.
References #
- Ueno, Tokihiro. “Chemical shifts of photoelectron and auger lines in Ag-or Cu-doped amorphous GeSe2 and As2Se3.” Japanese journal of applied physics 22.10R (1983): 1469. Read it online here.
- Rodriguez-Pereira, Jhonatan, et al. “Molybdenum diselenide thin films grown by atomic layer deposition: An XPS analysis.” Surface Science Spectra 27.2 (2020). Read it online here.
- Tufts, Bruce J., et al. “XPS and EXAFS studies of the reactions of cobalt (III) ammine complexes with gallium arsenide surfaces.” Journal of the American Chemical Society 112.13 (1990): 5123-5136. Read it online here.
