Interpretation of auger energy shifts of silicon in solid silicon compounds

Abstract

Chemical shifts of Auger transitions and photoelectron binding energies of silicon have been measured and interpreted using the quasi-atomic approach. The Si KL 2,3 L 2,3 and L 2,3 V 1 V 1 Auger transitions and the binding energies of Si 2 p and of the valence electrons at the maximum of the density of states V 1 have been investigated in solid silicon and in the compounds SiC, Si 3N 4, SiO 2, Na 2SiF 6 and T 3Si (T = V, Cr, Mn, Fe, Co, Ni). The relaxation-energy shift Δ R ea S(2 p, 2 p) describing the polarization effect (final-state effect) has been evaluated by AES and XPS measurements. Furthermore, the extra-atomic relaxation energy R ea D(2 p) of the 2 p electrons has been determined experimentally for silicon atoms in differing environments. This allows estimation of the potential parameter V(2 p) describing the potential effect (initial-state effect). In general R ea D(2 p) was found to be more sensitive to changes in chemical bonding than V2 p). The behaviour of the quasi-atomic Si V 1 electrons seems to be the converse.