How to calculate lower unoccupied molecular orbital (Lumo level for a given film using UPS Ultraviolet photoelectron spectroscopy data? also how to find bandgap and fermi level from these spectroscopy data?
UPS usually probes occupied states, exclusively, so the LUMO can't be determined from there. For unoccupied states, you could generally use inverse photoemission or tunneling spectroscopy.
If the bandgap of your species is really small, it could be overcome thermally. In that special case you could record a UPS at high temperatures and see whether a new component appears. But that's not generally applicable and you have to be careful not to evaporate dirt into your spectrometer.
If your substance accepts electrons easily, you could also consider Cs doping experiments in which the Cs valence electron occupies the LUMO; if you do this for various degrees, you can extrapolate down to a zero doping LUMO level.
Edit: I just saw you also asked about the Fermi level. If you have calculated your binding energy by Ebind=h*nu+Ebias-Ekin, the Fermi level will be the reference position Ebind=0.
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