Al Kα and Cu Kα 1 excited XPS of vanadium oxide and VF 3 powders: Measurement of the V 1s – KLL Auger parameters

Abstract

Al Kα ( hν = 1486.6 eV) excited XPS shows that powder samples of V 2O 3, V 2O 5 and VF 3 are surface contaminated and that the V 2O 3 can be cleaned by heating in vacuum at 400 °C. The greater sampling depth of Cu Kα 1 ( hν = 8047.8 eV) excited XPS allows measurement of the bulk V 1s – KL 2L 3 Auger parameters (APs) for these materials. The APs of VF 3 and V 2O 5, relative to V metal, fall into the range of values expected for metal fluorides and oxides with non-local final state core-hole screening, whereas the AP of V 2O 3 is significantly closer to that of V metal. We ascribe this to a greater final state valence orbital occupation following photionisation in V 2O 3, part of which results from metal-like screening.