Auger electron spectra of hydrogenated Si(111)-1x1 surface obtained from Si-L23VV Auger electron Si-2p photoelectron coincidence measurements

The Si-L23VV Auger electron Si-2p photoelectron coincidence spectra (Si-L23VV-Si-2p APECS) of a hydrogenated Si(111)-1x1 surface are measured with an analyzer that is used for electron-electron and electron-ion coincidence measurements of surfaces. The Si-L23VV-Si-2p APECS show a sharp peak, a small shoulder, and a broad large peak at electron kinetic energies of about 85, about 80.5, and about 70 eV, respectively. The clarity of the last two peaks is lower in the Si-L23VV-Si-2p APECS of a clean Si(111)-7x7 surface. We attribute the three peaks to the Si-L23V3pV3p, Si-L23V3pV3s, and Si-L23V3sV3s Auger lines, respectively. The three-peak structure indicates that the local density of states of the 3s + 3p band is reduced in the case of the hydrogenated Si(111)-1x1 surface. This finding is consistent with that of a previous study on valence electronic states of hydrogenated Si(111) using ultraviolet photoemission spectroscopy.