Basic XPS Information Section

 The Basic XPS Information Section provides fundamental XPS spectra, BE values, FWHM values, BE tables, overlays of key spectra, histograms and a table of XPS parameters.
The Advanced XPS Information Section is a collection of additional spectra, overlays of spectra, peak-fit advice, data collection guidance, material info,
common contaminants, degradation during analysis, auto-oxidation, gas capture study, valence band spectra, Auger spectra, and more.
Published literature references, and website links are summarized at the end of the advanced section.
→  Periodic Table – HomePage                XPS Database of Polymers               → Six (6) BE Tables


Vanadium (V)

 

Vanadinite – Pb5(VO4)3Cl  Vanadium – Vo Patronite – VS4

 

  Page Index
  • Pure Element Spectra with Peak-fits
  • IMFP and Cross-sections for Pure Element
  • Native Oxide Spectra with Peak-fits
  • Pure Oxide Spectra with Peak-fits
  • Overlays and Valence Band Spectra
  • Six (6) Tables of Chemical State BEs 
  • Histograms of NIST BEs
  • Advanced XPS Information Section
  • Peak-fits and Overlays of V Chemical Compounds
  • Quantitation and Atom %s
  • Flood Gun Effects on Native Oxide Spectra
  • Study of UHV Gas Capture after Cleaning
  • Auger Peaks and Spectra
  • Contamination
  • XPS Facts, Guidance, Information
  • Chemical State Spectra from Literature
  • Expert Knowledge & Explanations


Vanadium (Vo) Metal
Peak-fits, BEs, FWHMs, and Peak Labels

.
Vanadium (Vo) Metal
V (2p) Spectrum – raw spectrum
ion etched clean		 Vanadium (Vo) Metal
Peak-fit of V (2p) Spectrum (w/o asymm)
using 2p3/2 to 2p1/2 spin-orbit splitting for peak-fit

 
→  Periodic Table – HomePage  
Vanadium (Vo) Metal
V (2p) Spectrum – extended range 
 Vanadium (Vo) Metal
Peak-fit of V (2p) Spectrum (w asymm)
 

Survey Spectrum of Vanadium (Vo) Metal
with Peaks Integrated, Assigned and Labelled
→  Periodic Table 

XPS Signals for Vanadium (Vo) Metal

Spin-Orbit Term,  BE (eV) Value, and Scofield σ for Aluminum Kα X-rays (1486 eV, 8.33 Ang)

Overlaps Spin-Orbit Term BE (eV) Value Scofield σ from 1486 eV X-rays IMFP (TPP-2M) in Å
V (2s) 626 3.57 16.7
O (1s) overlaps V (2p1/2) 520 3.29 18.3
V (2p3/2) 512 6.37 18.3
V (3s) 66 0.538 24.5
V (3p) 37 0.996 24.9

σ:  abbreviation for the term Scofield Photoionization Cross-Section which is used with IMFP and TF to generate RSFs and atom% quantitation

Energy Loss Peaks

~534 eV
~649 eV

Auger Peaks

Energy Loss :  ~22 eV above peak max
Expected Bandgap for VO: xx eV 

*Scofield Cross-Section (σ) for C (1s) = 1.0

→  Periodic Table 

 

Valence Band Spectrum from Vo Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

→  Periodic Table 

 

Plasmon Peaks from Vo Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

V (2p) – Extended Range Spectrum V (2p) – Extended Range Spectrum – Vertically Zoomed
→  Periodic Table 
 

V (LMM) Auger Peaks from Vo Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 
 

Artefacts Caused by Argon Ion Etching

Vanadium Carbide(s)

can form when ion etched Reactive Metal Surfaces capture
Residual UHV Gases (CO, H2O, CH4 etc)

Argon Trapped in Vo

can form when Argon Ions are used
to removed surface contamination
 

Side-by-Side Comparison of
Fresh V Native Oxide & Vanadium Pentoxide (V2O5)
Peak-fits, BEs, FWHMs, and Peak Labels
 Fresh V Native-Oxide (5 min in air) V2O5
V (2p) from Fresh V Native Oxide
Flood Gun OFF
As-Measured, C (1s) at 285.14 eV 		 V (2p) from V2O5 – pellet
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV

 
→  Periodic Table 
C (1s) from fresh V Native Oxide
on Vanadium
As-Measured, C (1s) at 285.14 eV (Flood Gun OFF)
C (1s) shifts by 1.8 eV for Native V Oxide but V BE does not!

C (1s) from V2O5 – pellet 
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV
V Auger Peaks Overlap C (1s)

 
→  Periodic Table 
O (1s) from fresh V Native Oxide
on Vanadium
As-Measured, C (1s) at 285.14 eV (Flood Gun OFF)

O (1s) from V2O5 – pellet 
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV
 

 

 


Survey Spectrum of Fresh Vanadium (V) Native Oxide
with Peaks Integrated, Assigned and Labelled

→  Periodic Table 

 

 

Survey Spectrum of Vanadium Pentoxide (V2O5)
with Peaks Integrated, Assigned and Labelled


→  Periodic Table  

Overlays of V (2p) Spectra for
Fresh V Native-Oxide and V2O5

Caution: BEs from Grounded Native Oxides can be Misleading if Flood Gun is ON

 Overlay of V metal and Fresh V Native-Oxide – V (2p)
Native Oxide C (1s) = 285.14
(Flood gun OFF)
  Overlay of V metal and V2O5 – V (2p)
Pure Oxide C (1s) = 285.0 eV
Chemical Shift: 5.1
→  Periodic Table  Copyright ©:  The XPS Library 

 

Overlay of V (2p) 
Vo Metal, Fresh V Native-Oxide, & V2O5

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Valence Band Spectra
Vo, V2O5 

Vo
Ion etched clean		 V2O5 – pellet
Flood gun is ON,  Charge referenced so C (1s) = 285.0 eV


Overlay of Valence Band Spectra
from Vo and V2O5

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Vanadium Minerals, Gemstones, and Chemical Compounds

 
Pliniusite – Ca5(VO4)3F  Berdesinskiite – V2TiO5 Karelianite – V2O3  Schaeferite – (NaCa2)Mg2(VO4)3

→  Periodic Table 

 

Six (6) Chemical State Tables of V (2p) BEs

 

  • The XPS Library Spectra-Base
  • PHI Handbook
  • Thermo-Scientific Website
  • XPSfitting Website
  • Techdb Website
  • NIST Website

→  Periodic Table 

 

Notes of Caution when using Published BEs and BE Tables from Insulators and Conductors:

  • Accuracy of Published BEs
    • The accuracy depends on the calibration BEs used to calibrate the energy scale of the instrument.  Cu (2p3/2) BE can vary from 932.2 to 932.8 eV for old publications 
    • Different authors use different BEs for the C (1s) BE of the hydrocarbons found in adventitious carbon that appears on all materials and samples.  From 284.2 to 285.3 eV
    • The accuracy depends on when the authors last checked or adjusted their energy scale to produce the expected calibration BEs
  • Worldwide Differences in Energy Scale Calibrations
    • For various reasons authors still use older energy scale calibrations 
    • Some authors still adjust their energy scale so Cu (2p3/2) appears at 932.2 eV or 932.8 eV because this is what the maker taught them
    • This range causes BEs in the higher BE end to be larger than expected 
    • This variation increases significantly above 600 eV BE
  • Charge Compensation
    • Samples that behave as true insulators normally require the use of a charge neutralizer (electron flood gun with or without Ar+ ions) so that the measured chemical state spectra can be produced without peak-shape distortions or sloping tails on the low BE side of the peak envelop. 
    • Floating all samples (conductive, semi-conductive, and non-conductive) and always using the electron flood gun is considered to produce more reliable BEs and is recommended.
  • Charge Referencing Methods for Insulators
    • Charge referencing is a common method, but it can produce results that are less reliable.
    • When an electron flood gun is used, the BE scale will usually shift to lower BE values by 0.01 to 5.0 eV depending on your voltage setting. Normally, to correct for this flood gun induced shift, the BE of the hydrocarbon C (1s) peak maximum from adventitious carbon is used to correct for the charge induced shift.
    • The hydrocarbon peak is normally the largest peak at the lowest BE. 
    • Depending on your preference or training, the C (1s) BE assigned to this hydrocarbon peak varies from 284.8 to 285.0 eV.  Other BEs can be as low as 284.2 eV or as high as 285.3 eV
    • Native oxides that still show the pure metal can suffer differential charging that causes the C (1s) and the O (1s) and the Metal Oxide BE to be larger
    • When using the electron flood gun, the instrument operator should adjust the voltage and the XY position of the electron flood gun to produce peaks from a strong XPS signal (eg O (1s) or C (1s) having the most narrow FWHM and the lowest experimentally measured BE. 

→  Periodic Table 

Table #1

V (2p3/2) Chemical State BEs from:  “The XPS Library Spectra-Base”

C (1s) BE = 285.0 eV for TXL BEs
and C (1s) BE = 284.8 eV for NIST BEs

Element Atomic # Compound As-Measured by TXL or NIST Average BE Largest BE Hydrocarbon C (1s) BE  Source
V 23 V – element 512.2 eV 285.0 eV The XPS Library
V 23 V-P (N*1) 512.6 eV 284.8 eV Avg BE – NIST
V 23 V-Cl2 (N*1) 513 eV 284.8 eV Avg BE – NIST
V 23 VB2 (N*1) 513.2 eV 284.8 eV Avg BE – NIST
V 23 V-C 513.3 eV 513.5 eV 285.0 eV The XPS Library
V 23 V-N 513.6 eV 285.0 eV The XPS Library
V 23 V(OH)3 (N*1) 514.1 eV 284.8 eV Avg BE – NIST
V 23 V2O3 (N*2) 515.7 eV 515.8 eV 284.8 eV Avg BE – NIST
V 23 V-O2 (N*2) 515.7 eV 516.3 eV 284.8 eV Avg BE – NIST
V 23 V2O5 (N*15) 516.4 eV 517.7 eV 284.8 eV Avg BE – NIST
V 23 V-2O5 517.0 eV 285.0 eV The XPS Library
V 23 V-F 285.0 eV The XPS Library

Charge Referencing Notes

  • (N*number) identifies the number of NIST BEs that were averaged to produce the BE in the middle column.
  • The XPS Library uses Binding Energy Scale Calibration with Cu (2p3/2) BE = 932.62 eV and Au (4f7/2) BE = 83.98 eV.  BE (eV) Uncertainty Range:  +/- 0.2 eV
  • Charge Referencing of insulators is defined such that the Adventitious Hydrocarbon C (1s) BE (eV) = 285.0 eV.  NIST uses C (1s) BE = 284.8 eV 
  • Note:   Ion etching removes adventitious carbon, implants Ar (+), changes conductivity of surface, and degrades chemistry of various chemical states.
  • Note:  Ion Etching changes BE of C (1s) hydrocarbon peak.
  • TXL – abbreviation for: “The XPS Library” (https://xpslibrary.com).  NIST:  National Institute for Science and Technology (in USA)

→  Periodic Table 

Table #2

V (2p3/2) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Ulvac-PHI

Table #3

V (2p3/2) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical state Binding energy,
V (2p3/2)
V metal 512.3
V (II) 513.6
V (IV) 516.4
V2O3 517.1

→  Periodic Table 

Copyright ©:  Thermo Scientific 

Table #4

V (2p3/2) Chemical State BEs from:  “XPSfitting” Website

Chemical State BE Table derived by Averaging BEs in the NIST XPS database of BEs
C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Mark Beisinger

Table #5

V (2p3/2) Chemical State BEs from:  “Techdb.podzone.net” Website

 

XPS Spectra – Chemical Shift | Binding Energy
C (1s) BE = 284.6 eV

XPS(X線光電子分光法)スペクトル 化学状態 化学シフト ケミカルシフト

Element Level Compound B.E. (eV) min max
V 2p3/2 V 512.8 ±0.7 512.1 ～ 513.5
V 2p3/2 VB2 513.1 ±0.2 512.9 ～ 513.3
V 2p3/2 Metallocene 513.2 ±0.3 512.9 ～ 513.4
V 2p3/2 K4V(CN)6 513.2 ±0.2 513.0 ～ 513.4
V 2p3/2 V(acac)3 514.3 ±0.3 514.0 ～ 514.5
V 2p3/2 VN 514.4 ±0.3 514.1 ～ 514.6
V 2p3/2 VO(acac)2 515.1 ±0.3 514.8 ～ 515.3
V 2p3/2 VOSO4 516.0 ±0.3 515.7 ～ 516.2
V 2p3/2 VOCl2 516.5 ±0.3 516.2 ～ 516.7
V 2p3/2 Oxide 516.5 ±1.0 515.5 ～ 517.5
V 2p3/2 Vanadate 517.3 ±0.4 516.9 ～ 517.6

 

→  Periodic Table 

 


Histograms of NIST BEs for V (2p3/2) BEs

Important Note:  NIST Database defines Adventitious Hydrocarbon C (1s) BE = 284.8 eV for all insulators.

Histogram indicates:  512.4 eV for Vo based on 10 literature BEs Histogram indicates:  517.2 eV for V2O5 based on 18 literature BEs

Table #6


NIST Database of V (2p3/2) Binding Energies

NIST Standard Reference Database 20, Version 4.1

Data compiled and evaluated
by
Alexander V. Naumkin, Anna Kraut-Vass, Stephen W. Gaarenstroom, and Cedric J. Powell
©2012 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Important Note:  NIST Database defines Adventitious Hydrocarbon C (1s) BE = 284.8 eV for all insulators.

 

Element Spectral Line Formula Energy (eV) Reference
V 2p3/2 V 512.14  Click
V 2p3/2 V 512.15  Click
V 2p3/2 V 512.16  Click
V 2p3/2 V 512.30  Click
V 2p3/2 V 512.30  Click
V 2p3/2 V 512.40  Click
V 2p3/2 V 512.40  Click
V 2p3/2 V 512.40  Click
V 2p3/2 VP 512.60  Click
V 2p3/2 V 512.60  Click
V 2p3/2 V 512.70  Click
V 2p3/2 AuV3 (A2) 512.80  Click
V 2p3/2 [V(C5H5)2] 512.90  Click
V 2p3/2 [V(C5H5)2] 512.90  Click
V 2p3/2 V 512.90  Click
V 2p3/2 VCl2 513.00  Click
V 2p3/2 AuV3 (A15I) 513.00  Click
V 2p3/2 V2O3 513.10  Click
V 2p3/2 VB2 513.20  Click
V 2p3/2 K4[V(CN)6] 513.30  Click
V 2p3/2 [V(C7H7)(C5H5)] 513.30  Click
V 2p3/2 [VCl(C5H5)2] 513.80  Click
V 2p3/2 AuV3 (A15II) 513.80  Click
V 2p3/2 VS 513.90  Click
V 2p3/2 V(OH)3 514.10  Click
V 2p3/2 [V(OC(C2H5)3)3] 514.10  Click
V 2p3/2 [V(CH3C(O)CHC(O)CH3)3] 514.20  Click
V 2p3/2 [V(OSi(C6H5)3)3] 514.30  Click
V 2p3/2 VN 514.30  Click
V 2p3/2 VPS3 514.30  Click
V 2p3/2 V0.78PS3 514.30  Click
V 2p3/2 VPS3 514.30  Click
V 2p3/2 BaVS3 514.30  Click
V 2p3/2 BaV0.8Ti0.2S3 514.30  Click
V 2p3/2 VN 514.40  Click
V 2p3/2 V2O5 514.90  Click
V 2p3/2 VCl3 515.00  Click
V 2p3/2 [VO(CH3C(O)CHC(O)CH3)2] 515.10  Click
V 2p3/2 Y2.0V0.08Ti1.7Ox 515.20  Click
V 2p3/2 Y2.0V0.10Ti1.0Ox 515.20  Click
V 2p3/2 (NH4)2[VO(C2O4)2].2H2O 515.30  Click
V 2p3/2 V2O3 515.70  Click
V 2p3/2 V2O4 515.70  Click
V 2p3/2 V2O3 515.80  Click
V 2p3/2 O5SV 515.90  Click
V 2p3/2 (MoO3)22.5(TeO2)10(V2O5)67.5 516.00  Click
V 2p3/2 Ca0.05Y1.9V0.05Ti1.7Ox 516.00  Click
V 2p3/2 Ca0.2Y1.9V0.2Ti1.4Ox 516.00  Click
V 2p3/2 VO2 516.30  Click
V 2p3/2 V2O4 516.30  Click
V 2p3/2 C44H28N4OV 516.30  Click
V 2p3/2 VOCl2 516.40  Click
V 2p3/2 V2O4 516.50  Click
V 2p3/2 VOPO4 516.50  Click
V 2p3/2 VOPO4 516.50  Click
V 2p3/2 V2O5 516.60  Click
V 2p3/2 V2O5 516.60  Click
V 2p3/2 (CuO)0.18(V2O5)0.82 516.60  Click
V 2p3/2 BiO4V 516.70  Click
V 2p3/2 V2O5 516.70  Click
V 2p3/2 ((P2O5)0.40(V2O5)0.60)0.90(NiO)0.10 516.70  Click
V 2p3/2 H2V12-xMoxO31-y.nH2O 516.70  Click
V 2p3/2 VOPO4 516.70  Click
V 2p3/2 VOPO4 516.70  Click
V 2p3/2 V2O3 516.80  Click
V 2p3/2 H2V4Cr8O31.nH2O 516.80  Click
V 2p3/2 (CuO)0.37(V2O5)0.63 516.80  Click
V 2p3/2 (CuO)0.30(V2O5)0.70 516.80  Click
V 2p3/2 Cs3VO4 516.90  Click
V 2p3/2 Rb3VO4 516.90  Click
V 2p3/2 RhVO4 516.90  Click
V 2p3/2 V2O5 516.90  Click
V 2p3/2 ((P2O5)0.40(V2O5)0.60)0.85(NiO)0.15 516.90  Click
V 2p3/2 V2O2(P2O7) 516.90  Click
V 2p3/2 ((P2O5)0.40(V2O5)0.60)0.95(NiO)0.05 516.90  Click
V 2p3/2 V3Ag1.2Ce0.15O8+x 516.90  Click
V 2p3/2 V2O5(SiO2)117 516.90  Click
V 2p3/2 V2O5(SiO2)237 516.90  Click
V 2p3/2 VOPO4 516.90  Click
V 2p3/2 VOPO4 516.90  Click
V 2p3/2 Ca0.3Y1.9V0.2Ti1.1Ox 516.90  Click
V 2p3/2 V2O5 517.00  Click
V 2p3/2 NaVO3 517.00  Click
V 2p3/2 V0.78PS3 517.00  Click
V 2p3/2 (P2O5)0.40(V2O5)0.60 517.00  Click
V 2p3/2 NaVO3 517.00  Click
V 2p3/2 V0.78PS3 517.00  Click
V 2p3/2 V2O5(SiO2)545 517.00  Click
V 2p3/2 H2V6Cr6O31.nH2O 517.00  Click
V 2p3/2 V2O5 517.10  Click
V 2p3/2 ((P2O5)0.40(V2O5)0.60)0.98(NiO)0.02 517.10  Click
V 2p3/2 V2O5 517.20  Click
V 2p3/2 V2O5 517.20  Click
V 2p3/2 V2O3 517.20  Click
V 2p3/2 Na3VO4 517.30  Click
V 2p3/2 V2O5 517.30  Click
V 2p3/2 V2O5 517.30  Click
V 2p3/2 Sb0.92V0.92O4 517.30  Click
V 2p3/2 (CuO)0.40(V2O5)0.60 517.35  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 (MoO3)25(V2O5)75 517.40  Click
V 2p3/2 MgV2O6 517.40  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 V2O5 517.40  Click
V 2p3/2 Mn1.00V0.57O3.42 517.40  Click
V 2p3/2 Mn1.00V0.57O3.42 517.40  Click
V 2p3/2 (VO)2P2O7 517.40  Click
V 2p3/2 Li3VO4 517.50  Click
V 2p3/2 (CuO)0.20(V2O5)0.80 517.55  Click
V 2p3/2 (CuO)0.30(V2O5)0.70 517.55  Click
V 2p3/2 V2O5 517.60  Click
V 2p3/2 Li2.74V2O5 517.60  Click
V 2p3/2 CaV2O6 517.60  Click
V 2p3/2 (MoO3)23.75(TeO2)5(V2O5)71.25 517.60  Click
V 2p3/2 V2O5 517.60  Click
V 2p3/2 V2O5 517.60  Click
V 2p3/2 V2O5 517.60  Click
V 2p3/2 V2O5 517.60  Click
V 2p3/2 (MoO3)22.5(TeO2)10(V2O5)67.5 517.60  Click
V 2p3/2 (CuO)0.10(V2O5)0.90 517.60  Click
V 2p3/2 V2O5 517.65  Click
V 2p3/2 V2O5 517.70  Click
V 2p3/2 V2O5 517.70  Click
V 2p3/2 V2O5 517.70  Click
V 2p3/2 H2V12-xMoxO31-y.nH2O 517.70  Click
V 2p3/2 (NH4)5H3Mn3V12O40.15H2O 517.70  Click
V 2p3/2 NH4VO3 517.80  Click
V 2p3/2 VO(PO4) 518.00  Click
V 2p3/2 V2O5/Al2O3 518.10  Click
V 2p3/2 V2O5 518.30  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.40  Click
V 2p3/2 VOPO4 518.50  Click
V 2p3/2 VOPO4 518.50  Click
V 2p3/2 VOPO4 518.70  Click
V 2p3/2 VOPO4 518.70  Click
V 2p3/2 V2O5/SiO2 518.80  Click
V 2p3/2 ((C4H9)4N)2[V(C3S5)3] 523.10  Click
V 2p3/2 [Fe(C5H5)2][V(C3S5)3] 523.20  Click
V 2p3/2 [Ni(C5H5)2][V(C3S5)3] 523.20  Click
V 2p3/2 [Fe(C10H15)2][V(C3S5)3] 523.20  Click
V 2p3/2 [Fe(C6H7)2][V(C3S5)3] 523.50  Click
V 2p3/2 Fe[V(C3S5)3]2.3H2O 523.70  Click
V 2p3/2 Co[V(C3S5)3]2.3H2O 523.90  Click
V 2p3/2 (Li2O)0.25MnO2(V2O5)0.25 524.80  Click
V 2p3/2 V2O5 525.00  Click
V 2p3/2 NaVO3 525.20  Click

→  Periodic Table 

 

 

Statistical Analysis of Binding Energies in NIST XPS Database of BEs

 

 

→  Periodic Table 

 

Advanced XPS Information Section

Expert Knowledge, Spectra, Features, Guidance and Cautions  

for XPS Research Studies on Vanadium Materials

 

 

Expert Knowledge Explanations

→  Periodic Table 

 

Vanadium Chemical Compounds

 

Peak-fits and Overlays of Chemical State Spectra

Pure Vanadium, Vo:  V (2p)
Cu (2p3/2) BE = 932.6 eV		 V2O5:  V (2p)
C (1s) BE = 285.0 eV		 VF3:  V (2p)
C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Overlay of V (2p) Spectra shown Above

C (1s) BE = 285.0 eV

→  Periodic Table 

 

Fresh Native Oxide of Vanadium, (V)
Naturally Formed in lab air at 25 Co 1 atm after scraping clean (Age:  ~5 min)

Survey Spectrum from Fresh Native Oxide on Vo
Flood gun is OFF, C (1s) BE = 285.14 eV		 V (2p) Chemical State Spectrum from Fresh Native Oxide on Vo
Flood gun is OFF, C (1s) BE = 285.14 eV
  . 
O (1s) Chemical State Spectrum from Fresh Native Oxide on Vo
Flood gun is OFF, C (1s) BE = 285.14 eV		 C (1s) Chemical State Spectrum from Fresh Native Oxide on Vo
Flood gun is OFF, C (1s) BE = 285.14 eV

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

 

Vanadium Pent-oxide (V2O5)
pressed pellet or exposed bulk of single crystal

Survey Spectrum from V2O5
Flood gun is ON, C (1s) BE = 285.0 eV
 V (2p) Chemical State Spectrum from V2O5
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
O (1s) Chemical State Spectrum from V2O5
Flood gun is ON, C (1s) BE = 285.0 eV
 C (1s) Chemical State Spectrum from V2O5
Flood gun is ON, C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

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Vanadium Chemical Compounds

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Quantitation Details and Information

Quantitation by XPS is often incorrectly done, in many laboratories, by integrating only the main peak, ignoring the Electron Loss peak, and the satellites that appear as much as 30 eV above the main peak.  By ignoring the electron loss peak and the satellites, the accuracy of the atom% quantitation is in error.

When using theoretically calculated Scofield cross-section values, the data must be corrected for the transmission function effect, use the calculated TPP-2M IMFP values, the pass energy effect on the transmission function, and the peak area used for calculation must include the electron loss peak area, shake-up peak area, multiplet-splitting peak area, and satellites that occur within 30 eV of the main peak.

 

 

Flood Gun Effect on Native Oxide of Vanadium

 

Native Oxide of Vanadium Ribbon – Sample GROUNDED
versus
Native Oxide of Vanadium Ribbon – Sample FLOATING

 

Native Oxide of Vanadium Ribbon – Sample Grounded

Electron Flood Gun:  0 Voltage (FG OFF), Min Voltage versus Max Voltage

V (2p) Signal O (1s) Signal C (1s) Signal
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Native Oxide of Vanadium Ribbon – Sample Floating

Electron Flood Gun:  0 Voltage (FG OFF), Min Voltage versus Max Voltage

V 2p Signal O 1s Signal C 1s Signal
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→  Peri

 

 

XPS Study of UHV Gas Captured by Freshly Ion Etched Vanadium
Reveals Chemical Shifts and Chemical States that Develop from Highly Reactive Pure Vo

Surface was strongly Ar+ ion etched to remove all contaminants, and
then allowed to react overnight with the UHV Gases – CO, H2, H2O, O2 & CH4
that normally reside inside on the walls of the chamber, on the sample stage,
and on the nearby un-etched surface a total of 10-14 hours.  UHV pump was a Cryopump.
Initial spectra are at the front.  Final spectra are at the rear. Flood gun is OFF.
V (2p) Signal
  O (1s) Signal C (1s) Signal
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AES Study of UHV Gas Captured by Freshly Ion Etched Vanadium

Vanadium ribbon was ion etched and allowed to react with residual UHV gases overnight – ~14 hr run.

V (LMM) Signal:
V at front -> VOx at rear
V KE = 1118.1 eV,    VO KE = 1176.7 eV		 O (KLL) Signal:
V at front  -> VOx at rear
O KE = 504.8 eV
   

 
Chemical State Spectra from VOx using Charge Control by AES
 
V (KLL) Signal:
VO w charge control – JEOL Hemi-sphere (HSA) – 25 kV
High Energy Resolution Mode for Chemical States		 O (KLL) Signal:
VO w charge control – JEOL Hemi-sphere (HSA) – 25 kV
High Energy Resolution Mode for Chemical States
   

Features Observed

  • xx
  • xx
  • xx

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Vanadium Alloys

   
XxCu XxCu
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XxCu XxCu

 

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XPS Facts, Guidance & Information

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    Element Vanadium (V)
  
    Primary XPS peak used for Peak-fitting : V (2p)  
    Spin-Orbit (S-O) splitting for Primary Peak: Spin-Orbit splitting for “p” orbital, ΔBE = 7.6 eV
  
    Binding Energy (BE) of Primary XPS Signal: 512.1 eV
  
    Scofield Cross-Section (σ) Value: V (2p3/2) = 6.37      V(2p1/2) = 3.29
  
    Conductivity: V resistivity =  
Native Oxide suffers Differential Charing		  
    Range of V (2p) Chemical State BEs: 512 – 517 eV range   (Vo to VF3)  
Signals from other elements that overlap
V (2p) Primary Peak:		   xx (xx)
Bulk Plasmons:   ~xx eV above peak max for pure
Shake-up Peaks: ??
Multiplet Splitting Peaks:   ??

 

 

 General Information about
XXX Compounds:		   xx  
Cautions – Chemical Poison Warning

xx 

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Information Useful for Peak-fitting V (2p)

  • FWHM (eV) of V (2p3/2) from Pure Vo :  ~0.75 eV using 50 eV Pass Energy after ion etching:
  • FWHM (eV) of V (2p3/2) from V2O5:  ~1.3 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  512 eV for V (1s) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for V (2p):   

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General Guidelines for Peak-fitting XPS Signals

  • Typical Energy Resolution for Pass Energy (PE) setting used to measure Chemical State Spectra on Various XPS Instruments
    • Ag (3d5/2) FWHM (eV) = ~0.95 eV for PE 50 on Thermo K-Alpha
    • Ag (3d5/2) FWHM (eV) = ~1.00 eV for PE 80 on Kratos Nova
    • Ag (3d5/2) FWHM (eV) = ~0.95 eV for PE 45 on PHI VersaProbe
  • FWHM (eV) of Pure Elements: Ranges from 0.4 to 1.0 eV across the periodic table
  • FWHM of Chemical State Peaks in any Chemical Compound:  Ranges from 1.1 to 1.6 eV  (in rare cases FWHM can be 1.8 to 2.0 eV)
  • FWHM of Pure Element versus FWHM of Oxide:  Pure element FWHM << Oxide FWHM  (e.g. 0.8 vs 1.5 eV, roughly 2x)
  • If FWHM Greater than 1.6 eV:  When a peak FWHM is larger than 1.6 eV, it is best to add another peak to the peak-fit envelop.
  • BE (eV) Difference in Chemical States: The difference in chemical state BEs is typically 1.0-1.3 eV apart.  In rare cases, <0.8 eV.
  • Number of Peaks to Use:  Use minimum. Do not use peaks with FWHM < 1.0 eV unless it is a or a conductive compound.
  • Typical Peak-Shape:  80% G: 20% L,   or Voigt : 1.4 eV Gaussian and 0.5 eV Lorentzian
  • Spin-Orbit Splitting of Two Peaks (due to Coupling):  The ratio of the two (2) peak areas must be constrained.

Notes:

  • Other Oxidation States can appear as small peaks when peak-fitting
  • Pure element signals normally have asymmetric tails that should be included in the peak-fit.
  • Gaseous state materials often display asymmetric tails due to vibrational broadening.
  • Peak-fits of C (1s) in polymers include an asymmetric tail when the energy resolution is very high.
  • Binding energy shifts of some compounds are negative due to unusual electron polarization.

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Contaminants Specific to Vanadium

  • Vanadium develops a thick native oxide due to the reactive nature of clean Vanadium .
  • The native oxide of V Ox is 6-8 nm thick.
  • Vanadium thin films often have a low level of iron (Fe) in the bulk as a contaminant or to strengthen the thin film
  • Vanadium forms a low level of carbide when the surface is ion etched inside the analysis chamber

 

Commonplace Contaminants

  • Carbon and Oxygen are common contaminants that appear on nearly all surfaces. The amount of Carbon usually depends on handling.
  • Carbon is usually the major contaminant.  The amount of carbon ranges from 5-50 atom%.
  • Carbon contamination is attributed to air-borne organic gases that become trapped by the surface, oils transferred to the surface from packaging containers, static electricity, or handling of the product in the production environment.
  • Carbon contamination is normally a mixture of different chemical states of carbon (hydrocarbon, alcohol or ether, and ester or acid).
  • Hydrocarbon is the dominant form of carbon contamination. It is normally 2-4x larger than the other chemical states of carbon.
  • Carbonate peaks, if they appear, normally appear ~4.5 eV above the hydrocarbon C (1s) peak max BE.
  • Low levels of carbonate is common on many s that readily oxidize in the air.
  • High levels of carbonate appear on reactive oxides and various hydroxides.  This is due to reaction between the oxide and CO2 in the air.
  • Hydroxide contamination peak is due to the reaction with residual water in the lab air or the vacuum.
  • The O (1s) BE of the hydroxide (water) contamination normally appears 0.5 to 1.0 eV above the oxide peak
  • Sodium (Na), Potassium (K), Sulfur (S) and Chlorine (Cl) are common trace to low level contaminants
  • To find low level contaminants it is very useful to vertically expand the 0-600 eV region of the survey spectrum by 5-10X
  • A tiny peak that has 3 or more adjacent data-points above the average noise of the background is considerate to be a real peak
  • Carbides can appear after ion etching various reactive s.  Carbides form due to the residual CO and CH4 in the vacuum.
  • Ion etching can produce low oxidation states of the material being analyzed.  These are newly formed contaminants.
  • Ion etching polymers by using standard Ar+ ion guns will destroy the polymer, converting it into a graphitic type of carbon

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Data Collection Guidance

  • Chemical state differentiation can be difficult
  • Collect principal V (2p) peak.
  • Long time exposures (high dose) to X-rays can degrade various polymers, catalysts, high oxidation state compounds
  • During XPS analysis, water or solvents can be lost due to high vacuum or irradiation with X-rays or Electron flood gun
  • Auger signals can sometimes be used to discern chemical state shifts when XPS shifts are very small

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Data Collection Settings for Vanadium (V)

  • Conductivity:  Vanadium readily develops a native oxide that is sensitive to Flood Gun – Differential Charging Possible – float sample recommended
  • Primary Peak (XPS Signal) used to measure Chemical State Spectra:  V (2p) at 512  eV
  • Recommended Pass Energy for Measuring Chemical State Spectrum:  40-50 eV    (Produces Ag (3d5/2) FWHM ~0.7 eV)
  • Recommended # of Scans for Measuring Chemical State Spectrum:  4-5 scans normally   (Use 10-25 scans to improve S/N)
  • Dwell Time:  50 msec/point
  • Step Size:  0.1 eV/point   (0.1 eV/step or 0.1 eV/channel)
  • Standard BE Range for Measuring Chemical State Spectrum:  500 – 530 eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  490 – 590 eV
  • Recommended BE Range for Survey Spectrum:  -10 to 1,100 eV   (above 1,100 eV there are no useful XPS signals, except for Ge and Ga)
  • Typical Time for Survey Spectrum:  3-5 minutes for newer instruments, 5-10 minutes for older instruments
  • Typical Time for a single Chemical State Spectrum with high S/N:  5-10 minutes for newer instruments, 10-15 minutes for older instruments 

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Effects of Argon Ion Etching

  • Carbides appear after ion etching V and various reactive s.  Carbides form due to the residual CO and CH4 in the vacuum.
  • Ion etching can produce low oxidation states of the material being analyzed.  These are newly formed contaminants.
  • Ion etching polymers by using standard Ar+ ion guns will destroy the polymer, converting it into a graphitic type of carbon

 

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Copyright ©:  The XPS Library 
Gas Phase XPS or UPS Spectra

 

Chemical State Spectra from Literature

End of File