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


 

Silver (Ag)

Argentum

Bromoargyrite – AgBr Silver – Ago Iodoargyrite – AgI

 

  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 Ag 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


Silver (Ago) Metal

Peak-fits, BEs, FWHMs, and Peak Labels


  .
Silver (Ago) Metal
Ag (3d) Spectrum – raw spectrum

ion etched clean
Silver (Ago) Metal
Peak-fit of Ag (3d) Spectrum
w/o asymm

 Periodic Table – HomePage  
Silver (Ago) Metal
Ag (3d) Spectrum –
extended range 

Silver (Ago) Metal
Peak-fit of Ag (3d) Spectrum (w asymm)

 

Silver (Ago) Metal
Ag (4s) and (4p) Spectrum
 
 

 

Survey Spectrum of Silver (Ago) Metal
with Peaks Integrated, Assigned and Labelled

 


 Periodic Table 

XPS Signals for Silver, (Ago) 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
Fe (2p) overlaps Ag (3s) 720 2.93 12.2
Ag (3p1/2) 604 4.03 13.8
Te (3d) overlaps Ag (3p3/2) 573 8.06 13.8
Ag (3d3/2) 374.29 7.38 16.0
Ag (3d5/2) 368.28 10.66 16.0
Si (2p) & Hg (4f) overlap Ag (4s) 97 0.644 18.9
Na (2s) overlaps Ag (4p) 59 2.06 19.3

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

Energy Loss Peaks

Auger Peaks

Energy Loss    Intrinsic Plasmon Peak:  ~xx eV above peak max
Expected Bandgap for AgO:  ~1.1 eV
Work Function for AgO:  xx eV

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

 Periodic Table 


 

Valence Band Spectrum from Silver, Ago Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

 


 

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

Ag (3d) – Extended Range Spectrum Ag (3d) – Extended Range Spectrum – Vertically Zoomed

 

Comparison of Plasmon and Energy Loss Peaks for
Ago metal and AgF2
Ago metal – Plasmon Detail AgF2 Energy Loss Detail
 Periodic Table 

 

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

Ago Metal – main Auger peak Ago Metal – full Auger range

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 


 

Artefacts Caused by Argon Ion Etching

Silver Carbide(s)

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

Argon Trapped in Ago

can form when Argon Ions are used
to removed surface contamination

na na

 

Side-by-Side Comparison of
Ag Native Oxide & Silver Oxide (AgO)
Peak-fits, BEs, FWHMs, and Peak Labels

Ag Native Oxide AgO
Ag (3d) from Ag Native Oxide
Flood Gun OFF
As-Measured, C (1s) at 285.2 eV 
Ag (3d) from AgO – pressed powder
Flood Gun OFF
AS-Measured, C (1s)  at 284.2 eV

 


 Periodic Table   
Ag Native Oxide AgO
C (1s) from Ag Native Oxide
As-Measured, C (1s) at 285.2 eV
Flood Gun OFF

C (1s) from AgO – pressed powder
Flood Gun OFF
AS-Measured, C (1s)  at 284.2 eV
Carbonate seems to be present


 Periodic Table 
 
Ag Native Oxide AgO
O (1s) from Ag Native Oxide
As-Measured, C (1s) at 285.2 eV
Flood Gun OFF

O (1s) from AgO – pressed powder
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV


 Periodic Table 
Ag Native Oxide AgF2
Ag (LMM) Auger Peaks from Ag Native Oxide
As-Measured, C (1s) at 285.2 eV (Flood Gun OFF)

Ag (LMM) Auger Peaks from AgF2 – pressed powder
Flood Gun ON
AS-Measured, C (1s)  at 285.0 eV


 

 

Survey Spectrum of Ag Native Oxide
with Peaks Integrated, Assigned and Labelled

 Periodic Table 


 

Survey Spectrum of Silver Oxide (AgO)
with Peaks Integrated, Assigned and Labelled

 

 Periodic Table  


Overlays of Ag (3d) Spectra for
Ag Native Oxide and AgO

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

 Overlay of Ago metal and Ag Native Oxide – Ag (3d)
Native Oxide C (1s) = 285.2 eV
Flood gun OFF

 
 Overlay of Ago metal and AgO – Ag (3d)
Pure Oxide C (1s) = 285.0 eV
Chemical Shift:  -0.7 eV
 Periodic Table  Copyright ©:  The XPS Library 

 

Overlay of Ag (3d)
Ago Metal, Ag Native Oxide, & Silver Oxide, AgO   

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 


 

Valence Band Spectra
Ago, AgO 

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


Overlay of Valence Band Spectra
for Ago metal and AgO


 

 

Overlay of Valence Band Spectra
for Ago metal, Ag2O and AgO

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 



 

Silver Minerals, Gemstones, and Chemical Compounds

 

Acanthite – Ag2S Aguilarite – Ag4SeS Laffittite – AgHgAsS3 Marrite – AgPbAsS3

 Periodic Table 



 

Six (6) Chemical State Tables of Ag (3d5/2) 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) 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 (3d5/2) 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

Ag (3d5/2) 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
Ag 47 Ag-2CO3 (N*2) 367.5 eV 367.8 eV 284.8 eV Avg BE – NIST
Ag 47 Ag-O 367.6 eV 285.0 eV The XPS Library
Ag 47 Ag-F (N*2) 367.7 eV 367.8 eV 284.8 eV Avg BE – NIST
Ag 47 Ag-2SO4 (N*3) 367.8 eV 368.3 eV 284.8 eV Avg BE – NIST
Ag 47 Ag-I (N*3) 367.8 eV 368.1 eV 284.8 eV Avg BE – NIST
Ag 47 Ag-Cl (N*1) 368.1 eV 284.8 eV Avg BE – NIST
Ag 47 Ag – element 368.2 eV 285.0 eV The XPS Library
Ag 47 Ag-NO3 (N*1) 368.2 eV 284.8 eV Avg BE – NIST
Ag 47 Ag-2S 368.3 eV 285.0 eV The XPS Library
Ag 47 Ag-2O 368.3 eV 285.0 eV The XPS Library
Ag 47 AgGaSe2 (N*1) 368.4 eV 284.8 eV Avg BE – NIST

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 (3d5/2) 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

Ag (3d5/2) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

 Periodic Table 

Copyright ©:  Ulvac-PHI


Table #3

Ag (3d5/2) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical state Binding energy (eV),
Ag (3d5/2)
Bromyrite (AgBr) 367.5
Ag metal 368.2

 Periodic Table 

Copyright ©:  Thermo Scientific 


Table #4

Ag (3d5/2) 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

Ag (3d5/2) 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
Ag 3d5/2 AgF2 367.3 ±0.3 367.0 367.5
Ag 3d5/2 Ag2CO3 367.5 ±0.3 367.2 367.8
Ag 3d5/2 Oxides 367.7 ±0.4 367.3 368.0
Ag 3d5/2 AgF 367.8 ±0.3 367.5 368.0
Ag 3d5/2 Ag2S 368.0 ±0.3 367.7 368.3
Ag 3d5/2 AgI 368.0 ±0.3 367.7 368.3
Ag 3d5/2 Sulfate 368.1 ±0.3 367.8 368.4
Ag 3d5/2 Ag 368.2 ±0.1 368.1 368.3
Ag 3d5/2 Alloys 368.4 ±0.4 368.0 368.8
Ag 3d5/2 Ag(OAc) 368.5 ±0.3 368.2 368.8
Ag 3d5/2 AgOOCCF3 368.7 ±0.3 368.4 369.0

 

 Periodic Table 



 


Histograms of NIST BEs for Ag (3d5/2) BEs

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

Histogram indicates:  368.2 eV for Ago based on 24 literature BEs Histogram indicates:  367.9 eV for Ag2O based on 7 literature BEs

Histogram indicates:  367.3 eV for AgO based on 6 literature BEs

Table #6


NIST Database of Ag (3d5/2) 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
Ag 3d5/2 AgF2 367.30  Click
Ag 3d5/2 AgO 367.30  Click
Ag 3d5/2 AgO 367.30  Click
Ag 3d5/2 AgO 367.30  Click
Ag 3d5/2 [Ag(SO4)2(C5H4NCl)4] 367.40  Click
Ag 3d5/2 AgO 367.40  Click
Ag 3d5/2 Ag5.3Pt94.7 367.40  Click
Ag 3d5/2 Ag2CO3 367.50  Click
Ag 3d5/2 AgAuTe4 367.50  Click
Ag 3d5/2 V3Ag1.2Ce0.15O8+x 367.50  Click
Ag 3d5/2 AgO 367.60  Click
Ag 3d5/2 Ag/SnO2 367.60  Click
Ag 3d5/2 Ag24.5Pd75.5 367.60  Click
Ag 3d5/2 Ag25.9Pd74.1 367.60  Click
Ag 3d5/2 (Ag2O)51(P2O5)49 367.65  Click
Ag 3d5/2 AgF 367.70  Click
Ag 3d5/2 Ag2O 367.70  Click
Ag 3d5/2 Ag2O 367.70  Click
Ag 3d5/2 Ag2O 367.70  Click
Ag 3d5/2 (N(H)-C(CH3)=C(CN)-C(S)-S-CH2-C(O)-O-C2H5)Ag 367.70  Click
Ag 3d5/2 Ag2CO3 367.80  Click
Ag 3d5/2 AgI 367.80  Click
Ag 3d5/2 AgCuSe 367.80  Click
Ag 3d5/2 AgF 367.80  Click
Ag 3d5/2 Ag2SO4 367.80  Click
Ag 3d5/2 Ag2SO4 367.80  Click
Ag 3d5/2 Ag2O 367.80  Click
Ag 3d5/2 Ag2Se 367.80  Click
Ag 3d5/2 AgI 367.80  Click
Ag 3d5/2 Ag2SO4 367.80  Click
Ag 3d5/2 AgF 367.80  Click
Ag 3d5/2 (Ag2O)62(P2O5)38 367.80  Click
Ag 3d5/2 (Ag2O)69.7(P2O5)30.3 367.80  Click
Ag 3d5/2 Ag2CO3 367.80  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.14(TeO2)0.56 367.80  Click
Ag 3d5/2 (Ag2O)0.30(TeO2)0.70 367.80  Click
Ag 3d5/2 (Ag2O)0.3(TeO2)0.7 367.80  Click
Ag 3d5/2 Pd60Ag40/C 367.85  Click
Ag 3d5/2 Pd65Ag35/C 367.85  Click
Ag 3d5/2 Ag 367.90  Click
Ag 3d5/2 Ag2O 367.90  Click
Ag 3d5/2 Ag2O 367.90  Click
Ag 3d5/2 Pd49Ag51/C 367.90  Click
Ag 3d5/2 Ag/Pt 367.90  Click
Ag 3d5/2 (Ag2O)66.1(P2O5)33.9 367.90  Click
Ag 3d5/2 Ag1.5Cu0.5S 367.90  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.40(P2O5)0.10 367.90  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.25(P2O5)0.25 367.90  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.30(P2O5)0.20 367.90  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.35(P2O5)0.15 367.90  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.45(P2O5)0.05 367.90  Click
Ag 3d5/2 AgI 368.00  Click
Ag 3d5/2 AgO 368.00  Click
Ag 3d5/2 AgMo6S8 368.00  Click
Ag 3d5/2 Ag2S 368.00  Click
Ag 3d5/2 Ag95.8Pt4.2 368.00  Click
Ag 3d5/2 Ag2S 368.00  Click
Ag 3d5/2 (Ag2O)53(P2O5)47 368.00  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.56(TeO2)0.14 368.00  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.42(TeO2)0.28 368.00  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.28(TeO2)0.42 368.00  Click
Ag 3d5/2 (Ag2O)0.1(TeO2)0.9 368.00  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.20(P2O5)0.30 368.00  Click
Ag 3d5/2 Ag/Pt 368.01  Click
Ag 3d5/2 Ag/Ru 368.03  Click
Ag 3d5/2 Ag95Sn5 368.04  Click
Ag 3d5/2 Ag 368.10  Click
Ag 3d5/2 Ag 368.10  Click
Ag 3d5/2 Ag 368.10  Click
Ag 3d5/2 Ag 368.10  Click
Ag 3d5/2 Ag 368.10  Click
Ag 3d5/2 AgCl 368.10  Click
Ag 3d5/2 AgO 368.10  Click
Ag 3d5/2 Ag2S 368.10  Click
Ag 3d5/2 Ag2WO4 368.10  Click
Ag 3d5/2 Ag2WO4 368.10  Click
Ag 3d5/2 Ag98.9Pt1.1 368.10  Click
Ag 3d5/2 AgI 368.10  Click
Ag 3d5/2 I2/Ag 368.10  Click
Ag 3d5/2 AgCl 368.10  Click
Ag 3d5/2 (Ag2O)0.5(TeO2)0.5 368.10  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.10(P2O5)0.40 368.10  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.15(P2O5)0.35 368.10  Click
Ag 3d5/2 Ag 368.16  Click
Ag 3d5/2 Ag/Ru 368.17  Click
Ag 3d5/2 Ag/Ru 368.19  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 Ag 368.20  Click
Ag 3d5/2 AgO(O)CCH3 368.20  Click
Ag 3d5/2 Ag2O 368.20  Click
Ag 3d5/2 Ag2S 368.20  Click
Ag 3d5/2 AgNO3 368.20  Click
Ag 3d5/2 (Ag2O)60(P2O5)40 368.20  Click
Ag 3d5/2 Ag98.9Pt1.1 368.20  Click
Ag 3d5/2 I2/Ag 368.20  Click
Ag 3d5/2 AgNO3 368.20  Click
Ag 3d5/2 Ag/(-C6H4S-)n 368.20  Click
Ag 3d5/2 Ag71Cu29 368.20  Click
Ag 3d5/2 (Ag2O)0.5(P2O5)0.5 368.20  Click
Ag 3d5/2 Ag 368.21  Click
Ag 3d5/2 Ag 368.22  Click
Ag 3d5/2 Ag 368.22  Click
Ag 3d5/2 Ag 368.23  Click
Ag 3d5/2 Ag 368.26  Click
Ag 3d5/2 Ag 368.27  Click
Ag 3d5/2 Ag 368.27  Click
Ag 3d5/2 Ag/Pt 368.27  Click
Ag 3d5/2 Ag/Pt 368.27  Click
Ag 3d5/2 Ag/Ru 368.27  Click
Ag 3d5/2 Ag 368.29  Click
Ag 3d5/2 Ag 368.30  Click
Ag 3d5/2 Ag 368.30  Click
Ag 3d5/2 Ag2SO4 368.30  Click
Ag 3d5/2 (AgI)57.1(Ag2O)28.6(P2O5)14.3 368.30  Click
Ag 3d5/2 I2/Ag 368.30  Click
Ag 3d5/2 AgO(O)CC6H5 368.30  Click
Ag 3d5/2 AgPO3 368.30  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.70 368.30  Click
Ag 3d5/2 Ag28.6Au17.1Cu54.3 368.30  Click
Ag 3d5/2 (Ag2O)0.30(B2O3)0.49(TeO2)0.21 368.30  Click
Ag 3d5/2 Ag 368.40  Click
Ag 3d5/2 AgO(O)CCH3 368.40  Click
Ag 3d5/2 AgGaSe2 368.40  Click
Ag 3d5/2 [Ag(C6H5CONCSN(C2H5)2)] 368.40  Click
Ag 3d5/2 Ag2O 368.40  Click
Ag 3d5/2 (AgI)50(Ag2O)30(P2O5)20 368.40  Click
Ag 3d5/2 (AgI)55.0(Ag2O)25.0(P2O5)10.0 368.40  Click
Ag 3d5/2 Ag/(-C6H4S-)n 368.40  Click
Ag 3d5/2 (AgPO3)0.90S0.10 368.40  Click
Ag 3d5/2 Ag/C6H5SH 368.40  Click
Ag 3d5/2 (Ag2O)0.50(TeO2)0.05(P2O5)0.45 368.40  Click
Ag 3d5/2 (AgI)50.0(Ag2O)33.3(P2O5)16.7 368.45  Click
Ag 3d5/2 (AgI)66.7(Ag2O)25(P2O5)8.3 368.50  Click
Ag 3d5/2 (AgI)50.0(Ag2O)25.0(P2O5)25.0 368.50  Click
Ag 3d5/2 (AgI)60(Ag2O)30(P2O5)10 368.50  Click
Ag 3d5/2 (AgI)60.0(Ag2O)25.0(P2O5)15.0 368.50  Click
Ag 3d5/2 Pd85Ag15/C 368.50  Click
Ag 3d5/2 (AgPO3)0.95S0.05 368.50  Click
Ag 3d5/2 [(Pt2(P(C6H5)3)4S2)2Ag2][NO3]2 368.50  Click
Ag 3d5/2 Zn/Ag/Ru 368.52  Click
Ag 3d5/2 (AgI)65.0(Ag2O)23.3(P2O5)11.7 368.55  Click
Ag 3d5/2 [Ag(N2(-CH2CH2(O)CH2CH2(O)CH2CH2-)3)]NO3 368.60  Click
Ag 3d5/2 [Ag(C5H4NCl)2NO3] 368.60  Click
Ag 3d5/2 Pd90Ag10/C 368.60  Click
Ag 3d5/2 (AgPO3)0.80S0.20 368.60  Click
Ag 3d5/2 Ag/(-C6H4S-)n 368.70  Click
Ag 3d5/2 (AgPO3)0.70S0.30 368.70  Click
Ag 3d5/2 (AgPO3)0.75S0.25 368.70  Click
Ag 3d5/2 Ag/Pt 368.78  Click
Ag 3d5/2 AgC2F3O2 368.80  Click
Ag 3d5/2 Ag2S 368.80  Click
Ag 3d5/2 Ag/(-C6H4S-)n 368.80  Click
Ag 3d5/2 (AgPO3)0.85S0.15 368.80  Click
Ag 3d5/2 Ag2Se 369.00  Click
Ag 3d5/2 Na28.3Ag25.5Al54Si138O184 369.10  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 Silver Materials

 


 

Expert Knowledge Explanations

 Periodic Table 


 

Silver Chemical Compounds


Peak-fits and Overlays of Chemical State Spectra

Pure Silver, Ago:  Ag (3d)
Cu (2p3/2) BE = 932.6 eV
AgO:  Ag (3d)
C (1s) BE = 284.2 eV
AgF2:  Ag (3d)
C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 


 

Overlay of Ag (3d) Spectra shown Above

C (1s) BE = 285.0 eV

 

Chemical Shift between Ag and AgO:  -0.7 eV
Chemical Shift between Ag and AgF2:  +0.6 eV

 

 Periodic Table 


 

Silver Oxide (AgO)
pressed pellet 

Survey Spectrum from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV
Ag (3d) Chemical State Spectrum from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV

  .
O (1s) Chemical State Spectrum from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV
C (1s) Chemical State Spectrum from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV

  .
Valence Band Spectrum from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV
Auger Signals from AgO
Flood gun is OFF, C (1s) BE = 284.2 eV


Shake-up Features for AgO

 


 

Multiplet Splitting Features for
Silver Compounds

Ag metal – NO Splitting for Ag (4s) and (4p) AgO – NO Splitting Peaks for Ag (4s) and (4p)

 

 

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 

 


 


Silver Chemical Compounds

 

 Periodic Table 



 

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.

 

Quantitation from Pure, Homogeneous Binary Compound
composed of Silver – AgO

This section is focused on measuring and reporting the atom % quantitation that results by using:

  • Scofield cross-sections,
  • Spectra corrected to be free from Transmission Function effects
  • A Pass Energy that does not saturate the detector system in the low KE range (BE = 1000-1400 eV)
  • A focused beam of X-ray smaller than the field of view of the lens
  • An angle between the lens and the source that is ~55 deg that negates the effects of beta-asymmetry
  • TPP-2M inelastic mean free path values, and
  • Either a linear background or an iterated Shirley (Sherwood-Proctor) background to define peak areas

The results show here are examples of a method being developed that is expected to improve the “accuracy” or “reliability” of the atom % values produced by XPS.

 

 Periodic Table 


 

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

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.
Ag (3d) Signal
 O (1s) Signal C (1s) Signal
Reconstruction BE shift ~0.05 eV C (1s) at 284.7 eV from UHV gases
Copyright ©:  The XPS Library

 

AES Study of UHV Gas Captured by
Freshly Ion Etched Silver 

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

Ag (LMM) Signal:
Ag at front -> AgO X at rear 
Ag KE = 347.0 eV,    AgO KE = 347.1 eV
O (KLL) Signal:
Ag at front -> AgO X at rear 
O KE = 509.7 eV
C (KLL) Signal:
Ag at front -> AgO X at rear 
O KE = 256.6 eV
   
     
 

Features Observed

  • xx
  • xx
  • xx

 Periodic Table 


 

 

 

Silver Alloys

   
XxCu XxCu
 Periodic Table   
XxCu XxCu

 

Copyright ©:  The XPS Library 

 



 

XPS Facts, Guidance & Information

 Periodic Table 

    Element Silver (Ag)
 
    Primary XPS peak used for Peak-fitting: Ag (3d5/2)  
    Spin-Orbit (S-O) splitting for Primary Peak: Spin-Orbit splitting for “d” orbital, ΔBE = 6.1 eV
 
    Binding Energy (BE) of Primary XPS Signal: 368.2 eV
 
    Scofield Cross-Section (σ) Value: Ag (3d5/2) = 10.66      Ag (3d3/2) = 7.38
 
    Conductivity: Ag resistivity =  
Native Oxide suffers Differential Charing
 
    Range of Ag (3d5/2) Chemical State BEs: 367 – 372 eV range   (Ago to AgF2)  
Signals from other elements that overlap
Ag (3d5/2) Primary Peak:
  xx (xx)
Bulk Plasmons:   ~xx eV above peak max for pure
Shake-up Peaks: xx
Multiplet Splitting Peaks:   xx

 

 

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

xx 

Copyright ©:  The XPS Library 

 Periodic Table 



 

Information Useful for Peak-fitting Ag (3d5/2)

  • FWHM (eV) of Ag (3d5/2) for Pure Ago ~0.6 eV using 25 eV Pass Energy after ion etching:
  • FWHM (eV) of Ag (3d5/2) for AgO:  ~1.1 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  368 eV for Ag (3d5/2) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for Ag (3d5/2):  xxxx

 Periodic Table 


 

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.

 Periodic Table 


 

Contaminants Specific to Silver

  • Silver develops a thick native oxide due to the reactive nature of clean Silver.
  • The native oxide of Ag Ox is 1-3 nm thick.
  • Silver thin films often have a low level of iron (Fe) in the bulk as a contaminant or to strengthen the thin film
  • Silver 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

 Periodic Table 


 

Data Collection Guidance

  • Chemical state differentiation can be difficult
  • Collect principal Ag (3d) 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

 Periodic Table 


 

Data Collection Settings for Silver (Ag)

  • Conductivity:  Silver 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:  Ag (3d5/2) at 368 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:  355 – 385 eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  350 – 400 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 

 Periodic Table 


 

Effects of Argon Ion Etching

  • Carbides appear after ion etching Ag and various reactive surfaces.  Carbides form due to the presence of 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

 

 Periodic Table 

Copyright ©:  The XPS Library 


Gas Phase XPS or UPS Spectra


 

Chemical State Spectra from Literature
xxx



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