Al Kα and Cu Kα1 excited XPS of vanadium oxide and VF3 powders: Measurement of the V 1s – KLL Auger parameters

Stoichiometric vanadium oxides studied by XPS

“…Hence, Mendialdua et al [1] has shown that the binding energy of oxygen O1s = 530.0 eV is the best energy reference for the vanadium oxides as the ratio between the oxygen (N O ) and vanadium (N V ) concentrations N O /N V for different vanadium oxides does not depict the differentiation between different oxide states. Moreover, it has been confirmed [1][2][3] that the difference in binding energies between the O1s (VO x ) core level, normally taken at 530.0 eV, and the V2p 3/2 level (Δ = BE(O1s)-BE (V2p 3/2 )) is better for use in the determination of the oxidation state of the vanadium. On the other hand, our results for all of the performed XPS scans for each standard clearly indicate a shift in the oxygen peak position with the change in oxidation state of vanadium ( Table 2).…”

“…However, the analysis of vanadium oxide standards in their as-received state, shown in Fig. 2, clearly indicate that all the obtained standards, regardless of the high chemical purity and storage under argon, are covered by a layer of vanadium pentoxide V 2 O 5 (peak position at 517.2 eV [1][2][3]11] ). Therefore, an accurate evaluation of standard XPS spectra for vanadium oxides at lower oxidation states is impossible by direct acquisition of the XPS spectra without the development of an additional procedure of V 2 O 5 -layer removal.…”

“…The Ar ion sputtering is not recommended for use in obtaining a representative surface on vanadium oxide standards because of the high sensitivity of vanadium oxides to ion bombardment detected. [3] 512. 40 2.00 --- [4] 512.10 ---- [8] 511.70 ---- [10] VO 512.70 1.10 531.…”

“…However, an analysis of the published V2p 3/2 binding energy values for various oxidation states of vanadium indicates that there is also a large spread of the reported values. [1][2][3][4][5][6][7][8][9][10][11][12] Because of the number of possible valence states of vanadium, a number of compounds in the vanadium-oxygen system can be formed. This includes stoichiometric oxides V 2 O 5 , VO 2 , V 2 O 3 , and VO, where vanadium is present in oxidation states V 5+ , V 4+ , V 3+ , and V 2+ , respectively.…”

[11]Anthrahelicene on InSb(001) c(8×2): A Low‐Temperature Scanning Probe Microscopy Study

“…In recent years, there has been growing interest in XPS and related experiments performed with X‐rays of much higher energies for both scientific and technological purposes. So‐called hard XPS is being applied with X‐rays from synchrotron‐light sources (with energies up to 15 keV) and with Cu Kα X‐ray sources (with an energy of 8.048 keV) to characterize film composition and buried interfaces of multilayer thin‐film samples and powders 13, 14, 15. In these applications, the higher X‐ray energies were needed to enable sample characterizations without removal of surface layers by ion sputtering.…”