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


Copper (Cu)

Cuprum

Cuprite – Cu2O Copper – Cuo Chalcocite – Cu2S

 

  Page Index
  • Expert Knowledge & Explanations


Copper (Cuo) Metal
Peak-fits, BEs, FWHMs, and Peak Labels

  .
Copper (Cuo) Metal
Cu (2p3/2) Spectrum – raw spectrum
ion etched clean		 Copper (Cuo) Metal
Peak-fit of Cu (2p3/2) Spectrum (w/o asymm)
used Voigt peak-shape, with 50% Gauss, no asymmetry
→  Periodic Table – HomePage  
Copper (Cuo) Metal
Cu (2p) Spectrum – extended range 
 Copper (Cuo) Metal
Cu (2p) Spectrum –  vertically expanded

 

Survey Spectrum of Copper (Cuo) Metal
with Peaks Integrated, Assigned and Labelled

 

→  Periodic Table 

XPS Signals for Copper, (Cuo) 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
  Cu (2s) 1097 5.46 8.0
  Cu (2p1/2) 952 8.66 10.1
Pr (3d) overlaps Cu (2p3/2) 932.6 16.73 10.1
Al (2s) overlaps Cu (3s) 122 0.957 19.6
Al (2p), Pt (4f) overlaps Cu (3p) 75 2.478 20.1

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

Plasmon and Satellite Peaks

Auger Peaks

Expected Bandgap for Cu2O: ~2 eV 

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

→  Periodic Table 

 

Valence Band Spectrum from Copper (Cuo) Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

 

 

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

Cu (2p) – Extended Range Spectrum Cu (2p) Extended Range Spectrum – Vertically Zoomed
 

 

Cu (LMM) Auger Peaks from Copper, Cuo Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching
Cuo Metal – High Resolution for Chemical State Analysis Cu Metal – all Auger peaks

  . 
Cu (3s) Cu (3p)

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Artefacts Caused by Argon Ion Etching

Copper Carbide(s)

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

Argon Trapped in Cuo

can form when Argon Ions are used
to removed surface contamination
na na

 

Side-by-Side Comparison of
Cu Native Oxide & Cupric Oxide, CuO
Peak-fits, BEs, FWHMs, and Peak Labels
Cu Native Oxide CuO
Cu (2p3/2) from Cu Native Oxide
Flood Gun OFF
As-Measured, C (1s) at 284.9 eV 		 Cu (2p3/2) from CuO – pressed powder
Flood Gun OFF
C (1s) at 285.0 eV

→  Periodic Table 
   
Cu Native Oxide CuO
C (1s) from Cu Native Oxide
on Copper
As-Measured, C (1s) at 284.9 eV (Flood Gun OFF)

C (1s) from CuO – pressed powder
Flood Gun OFF
C (1s) at 285.0 eV

 
  . 
Cu Native Oxide CuO
O (1s) from Cu Native Oxide
on Copper
As-Measured, C (1s) at 284.9 eV (Flood Gun OFF)

O (1s) from CuO – pressed powder
Flood Gun OFF
C (1s) at 285.0 eV
 

 
 
Cuo CuO
Cu (KLL) Auger Peaks from Cuo
ion etched clean

Cu (KLL) Auger Peaks from CuO – pressed powder
Flood Gun OFF, C (1s) at 285.0 eV


Overlay of Auger Peak
Cuo, Cu2O, and CuO

 


Survey Spectrum of Copper (Cu) Native Oxide
with Peaks Integrated, Assigned and Labelled

→  Periodic Table 

 

 

Survey Spectrum of Cupric Oxide (CuO)
with Peaks Integrated, Assigned and Labelled


→  Periodic Table  

 

Overlays of Cu (2p3/2) Spectra for:
Cuo metal, Cu Native Oxide, Cu2O, CuO, and CuF2

 

 Overlay of Cu (2p3/2)
Cuo metal and Cu Native Oxide
 (Flood gun OFF)
Native Oxide C (1s) = 284.9 
  Overlay of Cu (2p3/2)
Cuo metal and CuO
Flood Gun OFF
C (1s) at 285.0 eV,  Chemical Shift 1.0 eV
.
Overlay of Cu (2p3/2)
Cuo Metal, Cu Native Oxide, & CuO		 Expanded Overlay of Cu (2p3/2)
Cuo Metal, Cu Native Oxide, & CuO
Chemical Shift between Cu and CuO = 1.0 eV
  . 
Overlay of Cu (2p3/2)
Cuo metal, Cu2O, and CuO 		 Expanded Overlay of Cu (2p3/2)
Cuo metal, Cu2O, and CuO
C (1s) at 285.0 eV
Chemical Shift between Cu and Cu2O = 0.4 eV
Chemical Shift between Cu and CuO = 1.0 eV

 
Overlay of Cu (2p3/2)
Cuo metal, CuO, and CuF2		 Expanded Overlay of Cu (2p3/2)
Cuo metal, CuO, and CuF2
C (1s) at 285.0 eV
Chemical Shift between Cu and CuO = 1.0 eV
Chemical Shift between Cu and CuF2 = 0.6 eV

→  Periodic Table  Copyright ©:  The XPS Library 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Valence Band Spectra
Cuo, CuO 

Cuo
Ion etched clean		 CuO – pellet or fresh bulk
Flood Gun OFF,  C (1s) at 285.0 eV


Overlay of Valence Band Spectra
for Cuo metal and CuO

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Copper Minerals, Gemstones, and Chemical Compounds

 
Tenorite – CuO Marshite – CuI Covellite – CuS Santarosaite – CuB2O4

→  Periodic Table 

 

 

Six (6) Chemical State Tables of Cu (2p3/2) 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 (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

Cu (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
Cu 29 Cu2Se (N*3) 931.9 eV 932.5 eV 284.8 eV Avg BE – NIST
Cu 29 CuCl 931.9 eV   285.0 eV The XPS Library
Cu 29 CuI (N*1) 931.9 eV   284.8 eV Avg BE – NIST
Cu 29 CuS (N*5) 931.9 eV 932.5 eV 285.0 eV The XPS Library
Cu 29 Cu2Se 932.0 eV 932.6 eV 285.0 eV The XPS Library
Cu 29 CuCl (N*4) 932.1 eV 932.4 eV 284.8 eV Avg BE – NIST
Cu 29 YBaCuOx 932.1 eV   284.8 eV Avg BE – NIST
Cu 29 Cu2O (N*14) 932.2 eV 932.7 eV 284.8 eV Avg BE – NIST
Cu 29 Cu2S (N*6) 932.2 eV 932.7 eV 284.8 eV Avg BE – NIST
Cu 29 CuP2 (N*2) 932.2 eV 932.4 eV 284.8 eV Avg BE – NIST
Cu 29 CuNi (N*2) 932.3 eV 932.4 eV 284.8 eV Avg BE – NIST
Cu 29 Cu-S 932.3 eV   285.0 eV The XPS Library
Cu 29 Cu-2O 932.5 eV   285.0 eV The XPS Library
Cu 29 Cu – element 932.67 eV   285.0 eV The XPS Library
Cu 29 CuCN (N*2) 932.8 eV 933.1 eV 284.8 eV Avg BE – NIST
Cu 29 BiSrCaCuOx 932.9 eV   285.0 eV The XPS Library
Cu 29 BiSrCuOx 932.9 eV   285.0 eV The XPS Library
Cu 29 Cu-O 933.0 eV   285.0 eV The XPS Library
Cu 29 CuCN 933.1 eV   285.0 eV The XPS Library
Cu 29 CuO (N*15) 933.2 eV 934.2 eV 284.8 eV Avg BE – NIST
Cu 29 Cu (OH)2 (N*2) 934.4 eV 935.1 eV 284.8 eV Avg BE – NIST
Cu 29 Cu-(OH)2 934.4 eV   285.0 eV The XPS Library
Cu 29 Cu-Cl2 (N*6) 934.4 eV 935.6 eV 284.8 eV Avg BE – NIST
Cu 29 Cu-CO3 934.9 eV 935.2 eV 285.0 eV The XPS Library
Cu 29 CuSO4 (N*4) 934.9 eV 935.6 eV 284.8 eV Avg BE – NIST
Cu 29 Cu(NO3)2 (N*1) 935.5 eV   284.8 eV Avg BE – NIST
Cu 29 Cu-F2 936.1 eV 937.2 eV 285.0 eV The XPS Library
Cu 29 CuF2 (N*4) 936.1 rV 936.8 eV 284.8 eV Avg BE – NIST
Cu 29 Cu-2S     285.0 eV The XPS Library
Cu 29 Cu-C     285.0 eV The XPS Library
Cu 29 Cu-N     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

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

C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Ulvac-PHI

Table #3

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

C (1s) BE = 284.8 eV

Chemical state Binding energy (eV),
Cu (2p3/2)
Cu metal 933 eV
Cu (I) oxide 933 eV
Cu (II) oxide ~933.5 eV
Cu (II) carbonate dihydroxide 934.7 eV

→  Periodic Table 

Copyright ©:  Thermo Scientific 

Table #4

Cu (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

Cu (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
Cu 2p3/2 Cu2S 932.5 ±0.3 932.2 ～ 932.8
Cu 2p3/2 CuS 932.5 ±0.7 931.8 ～ 933.2
Cu 2p3/2 CuCl 932.5 ±0.3 932.2 ～ 932.8
Cu 2p3/2 Cu2O 932.5 ±0.3 932.2 ～ 932.8
Cu 2p3/2 Cu 932.7 ±0.2 932.5 ～ 932.8
Cu 2p3/2 Cu(OAc)2 933.3 ±1.6 931.7 ～ 934.9
Cu 2p3/2 CuO 933.8 ±0.3 933.5 ～ 934.0
Cu 2p3/2 Cu(salicylaldoxime) 934.0 ±0.3 933.7 ～ 934.2
Cu 2p3/2 CuCl2 935.0 ±0.7 934.3 ～ 935.7
Cu 2p3/2 Cu(OH)2 935.1 ±0.3 934.8 ～ 935.3
Cu 2p3/2 CuSO4 935.2 ±0.4 934.8 ～ 935.5

→  Periodic Table 

 

 

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

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

Histogram indicates:  932.6 eV for Cuo based on 28 literature BEs Histogram indicates:  932.4 eV for Cu2O based on 18 literature BEs

 

 
Histogram indicates:  933.6 eV for CuO based on 20 literature BEs Histogram indicates:  932.5 eV for Cu2S based on 9 literature BEs

 

Histogram indicates:  932.5 eV for CuS based on 8 literature BEs

 

Histogram indicates:  935.4 eV for CuSO4 based on 5 literature BEs

Table #6


NIST Database of Cu (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
Cu 2p3/2 [Cu(CN)4(P(C6H5)4)3] 931.10  Click
Cu 2p3/2 Cu2Mo3O10 931.60  Click
Cu 2p3/2 CuInSe2 931.80  Click
Cu 2p3/2 Cu(C2H3O2)2 931.80  Click
Cu 2p3/2 CuFe2S3 931.80  Click
Cu 2p3/2 Cu2Se 931.90  Click
Cu 2p3/2 Cu2Se 931.90  Click
Cu 2p3/2 CuI 931.90  Click
Cu 2p3/2 CuInSe2 931.90  Click
Cu 2p3/2 AgCuSe 931.90  Click
Cu 2p3/2 CuS 931.90  Click
Cu 2p3/2 CuS 931.90  Click
Cu 2p3/2 CuSe 932.00  Click
Cu 2p3/2 Cu2O 932.00  Click
Cu 2p3/2 Cu2O 932.00  Click
Cu 2p3/2 CuFeS2 932.00  Click
Cu 2p3/2 [CuI]3[Co(S2(CN(CH2)4)3)] 932.00  Click
Cu 2p3/2 CuCl 932.10  Click
Cu 2p3/2 CuBr 932.10  Click
Cu 2p3/2 CuGaS2 932.10  Click
Cu 2p3/2 CuS 932.10  Click
Cu 2p3/2 Cu2S 932.10  Click
Cu 2p3/2 Ag71Cu29 932.10  Click
Cu 2p3/2 CuCl 932.20  Click
Cu 2p3/2 Cu 932.20  Click
Cu 2p3/2 Cu 932.20  Click
Cu 2p3/2 Cu 932.20  Click
Cu 2p3/2 [Cu(C2H5O)2PS2] 932.20  Click
Cu 2p3/2 Cu2O 932.20  Click
Cu 2p3/2 Cu2O 932.20  Click
Cu 2p3/2 CuP2 932.20  Click
Cu 2p3/2 CuFeS2 932.20  Click
Cu 2p3/2 CuS 932.20  Click
Cu 2p3/2 CuS 932.20  Click
Cu 2p3/2 Cu2S 932.20  Click
Cu 2p3/2 Au3Cu 932.25  Click
Cu 2p3/2 Cu 932.30  Click
Cu 2p3/2 [CuCl2(P(C6H5)4)] 932.30  Click
Cu 2p3/2 [CuCCC6H5] 932.30  Click
Cu 2p3/2 CrCuO2 932.30  Click
Cu 2p3/2 Cu2O 932.30  Click
Cu 2p3/2 Cu2O 932.30  Click
Cu 2p3/2 Cu3AsS4 932.30  Click
Cu 2p3/2 CuS 932.30  Click
Cu 2p3/2 CuS 932.30  Click
Cu 2p3/2 Cu/Ni 932.30  Click
Cu 2p3/2 CuInS2 932.30  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.32  Click
Cu 2p3/2 [CuC6H5CCP(C6H5)3]4 932.40  Click
Cu 2p3/2 CuCl 932.40  Click
Cu 2p3/2 CuCl 932.40  Click
Cu 2p3/2 CuBr 932.40  Click
Cu 2p3/2 Cu2O 932.40  Click
Cu 2p3/2 Cu2O 932.40  Click
Cu 2p3/2 Cu2O 932.40  Click
Cu 2p3/2 Cu2O 932.40  Click
Cu 2p3/2 CuP2 932.40  Click
Cu 2p3/2 CuInS2 932.40  Click
Cu 2p3/2 CuCo2S4 932.40  Click
Cu 2p3/2 Cu2S 932.40  Click
Cu 2p3/2 Cu2S 932.40  Click
Cu 2p3/2 Cu/Ni 932.40  Click
Cu 2p3/2 CuFeS2 932.40  Click
Cu 2p3/2 Pd/Cu 932.40  Click
Cu 2p3/2 CuInS2 932.40  Click
Cu 2p3/2 AuCu 932.40  Click
Cu 2p3/2 Ag28.6Au17.1Cu54.3 932.40  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.41  Click
Cu 2p3/2 Au3Cu 932.41  Click
Cu 2p3/2 AuCu3 932.45  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.45  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.45  Click
Cu 2p3/2 AuCu3 932.47  Click
Cu 2p3/2 CuInSe2 932.49  Click
Cu 2p3/2 CuInSe2 932.49  Click
Cu 2p3/2 CuCl 932.50  Click
Cu 2p3/2 Cu 932.50  Click
Cu 2p3/2 Cu 932.50  Click
Cu 2p3/2 Cu2Se 932.50  Click
Cu 2p3/2 [N(C2H5)4]2[CuCl4] 932.50  Click
Cu 2p3/2 Cu2O 932.50  Click
Cu 2p3/2 Cu2O 932.50  Click
Cu 2p3/2 CuS 932.50  Click
Cu 2p3/2 Cu2S 932.50  Click
Cu 2p3/2 Cu2S 932.50  Click
Cu 2p3/2 (GeO2)0.5(Na2O)0.3(CuO)0.2 932.50  Click
Cu 2p3/2 O2/Cu/Ni 932.50  Click
Cu 2p3/2 O2/Cu/Ni 932.50  Click
Cu 2p3/2 O2/Cu/Ni 932.50  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.50  Click
Cu 2p3/2 Pd/Cu 932.50  Click
Cu 2p3/2 Cu1.87S 932.50  Click
Cu 2p3/2 Zn/Cu 932.50  Click
Cu 2p3/2 Zn/Cu 932.50  Click
Cu 2p3/2 CuGa5Se8 932.50  Click
Cu 2p3/2 AuCu7 932.51  Click
Cu 2p3/2 CuI 932.52  Click
Cu 2p3/2 AuCu 932.52  Click
Cu 2p3/2 Cu 932.53  Click
Cu 2p3/2 Cu 932.55  Click
Cu 2p3/2 Cu 932.57  Click
Cu 2p3/2 AuCu19 932.58  Click
Cu 2p3/2 CuCl 932.60  Click
Cu 2p3/2 Cu 932.60  Click
Cu 2p3/2 Cu 932.60  Click
Cu 2p3/2 Cu 932.60  Click
Cu 2p3/2 Cu 932.60  Click
Cu 2p3/2 Cu 932.60  Click
Cu 2p3/2 Cu64Zn36 932.60  Click
Cu 2p3/2 CuFeO2 932.60  Click
Cu 2p3/2 Cu2O 932.60  Click
Cu 2p3/2 Cu2O 932.60  Click
Cu 2p3/2 Cu2O 932.60  Click
Cu 2p3/2 Cu2O 932.60  Click
Cu 2p3/2 Cu2S 932.60  Click
Cu 2p3/2 O2/Cu/Ni 932.60  Click
Cu 2p3/2 La/Cu 932.60  Click
Cu 2p3/2 Pd/Cu 932.60  Click
Cu 2p3/2 Cu/Ni 932.60  Click
Cu 2p3/2 Cu/Ni 932.60  Click
Cu 2p3/2 Cu/Ni 932.60  Click
Cu 2p3/2 Cu 932.61  Click
Cu 2p3/2 Cu 932.62  Click
Cu 2p3/2 Cu 932.63  Click
Cu 2p3/2 Cu 932.66  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.66  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.66  Click
Cu 2p3/2 Cu 932.67  Click
Cu 2p3/2 Cu 932.67  Click
Cu 2p3/2 Cu 932.67  Click
Cu 2p3/2 Ti(OCH(CH3)2)4 932.67  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 932.69  Click
Cu 2p3/2 [Cu(-C-6H5N3)] 932.70  Click
Cu 2p3/2 Cu 932.70  Click
Cu 2p3/2 Cu 932.70  Click
Cu 2p3/2 Cu 932.70  Click
Cu 2p3/2 CuO 932.70  Click
Cu 2p3/2 Cu2O 932.70  Click
Cu 2p3/2 Cu2O 932.70  Click
Cu 2p3/2 Cu2O 932.70  Click
Cu 2p3/2 Cu2S 932.70  Click
Cu 2p3/2 (GeO2)0.65(Na2O)0.3(CuO)0.05 932.70  Click
Cu 2p3/2 Cu/Si 932.70  Click
Cu 2p3/2 Cu(OH)2 932.70  Click
Cu 2p3/2 Cu/O2 932.70  Click
Cu 2p3/2 Cu/O2 932.70  Click
Cu 2p3/2 Cu/O2 932.70  Click
Cu 2p3/2 CuIn3Se5 932.70  Click
Cu 2p3/2 [CuClP(C6H5)3]4 932.80  Click
Cu 2p3/2 CuCN 932.80  Click
Cu 2p3/2 Cu 932.80  Click
Cu 2p3/2 Cu 932.80  Click
Cu 2p3/2 Cu 932.80  Click
Cu 2p3/2 [CuBr2(P(C6H5)4)] 932.80  Click
Cu 2p3/2 [CuCl((C6H5)3P)3] 932.80  Click
Cu 2p3/2 Cu2O 932.80  Click
Cu 2p3/2 (GeO2)0.6(Na2O)0.3(CuO)0.1 932.80  Click
Cu 2p3/2 Cu/NiO/Ni 932.80  Click
Cu 2p3/2 Cu/S 932.80  Click
Cu 2p3/2 (C112H166N2O4)n/Cu 932.80  Click
Cu 2p3/2 Al5Cu95 932.80  Click
Cu 2p3/2 (C100H158N2O4)n/Cu 932.80  Click
Cu 2p3/2 C82H114Br2N2O4/Cu 932.80  Click
Cu 2p3/2 Y/Cu 932.82  Click
Cu 2p3/2 [Cu(C5H10N)2(CS2)2] 932.90  Click
Cu 2p3/2 CuO 932.90  Click
Cu 2p3/2 Cu2S 932.90  Click
Cu 2p3/2 Cu2S 932.90  Click
Cu 2p3/2 La/Cu 932.90  Click
Cu 2p3/2 [CuCl(C7H6N2S)] 933.00  Click
Cu 2p3/2 Cu 933.00  Click
Cu 2p3/2 Cu/NiO/Ni 933.00  Click
Cu 2p3/2 Cu/NiO/Ni 933.00  Click
Cu 2p3/2 O2/Cu/NiO/Ni 933.00  Click
Cu 2p3/2 Al12Cu88 933.00  Click
Cu 2p3/2 CuInS2 933.00  Click
Cu 2p3/2 [(Pt2(P(C6H5)3)4S2Cu)2(mu-dppf)][PF6]2 933.00  Click
Cu 2p3/2 CuCN 933.10  Click
Cu 2p3/2 Cu 933.10  Click
Cu 2p3/2 [CuBr4(P(C6H5)4)3] 933.10  Click
Cu 2p3/2 O2/Cu3Sn 933.10  Click
Cu 2p3/2 Y/Cu 933.17  Click
Cu 2p3/2 [CuC(CN)3] 933.20  Click
Cu 2p3/2 [CuBr3(P(C6H5)4)] 933.20  Click
Cu 2p3/2 CuO 933.20  Click
Cu 2p3/2 CuO 933.20  Click
Cu 2p3/2 Al17Cu83 933.20  Click
Cu 2p3/2 Cu3Sn 933.20  Click
Cu 2p3/2 O2/Cu3Sn 933.20  Click
Cu 2p3/2 O2/Cu3Sn 933.20  Click
Cu 2p3/2 Cu/ZnO 933.22  Click
Cu 2p3/2 [CuS(C6H4NCS)] 933.30  Click
Cu 2p3/2 CuBr2 933.30  Click
Cu 2p3/2 CuBr2 933.30  Click
Cu 2p3/2 CuO 933.30  Click
Cu 2p3/2 CuO 933.40  Click
Cu 2p3/2 CuO 933.40  Click
Cu 2p3/2 YBa2Cu3O7 933.40  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.43  Click
Cu 2p3/2 Bi2Sr2CaCu2O8 933.47  Click
Cu 2p3/2 [CuCl3(P(C6H5)4)] 933.50  Click
Cu 2p3/2 CuO 933.50  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.51  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.51  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.54  Click
Cu 2p3/2 CuO 933.60  Click
Cu 2p3/2 CuO 933.60  Click
Cu 2p3/2 CuO 933.60  Click
Cu 2p3/2 CuO 933.60  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.60  Click
Cu 2p3/2 [Cu(HSCH2CHNH2COO)] 933.70  Click
Cu 2p3/2 CuFe2O4 933.70  Click
Cu 2p3/2 YBa2Cu3O7 933.70  Click
Cu 2p3/2 [Cu((C6H5)2PS(C2H5))2]ClO4 933.80  Click
Cu 2p3/2 [Cu((C6H5)PS(C6H5)2)2]ClO4 933.80  Click
Cu 2p3/2 CuFe2O4 933.80  Click
Cu 2p3/2 CuO 933.80  Click
Cu 2p3/2 CuO 933.80  Click
Cu 2p3/2 CuO 933.80  Click
Cu 2p3/2 CuO 933.80  Click
Cu 2p3/2 CuO 933.80  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 933.81  Click
Cu 2p3/2 [Cu(SC(SCH3)CHC(C6H5)O)2] 933.90  Click
Cu 2p3/2 CuO 933.90  Click
Cu 2p3/2 CuO 933.90  Click
Cu 2p3/2 CuO 933.90  Click
Cu 2p3/2 CuO 933.90  Click
Cu 2p3/2 [Cu(HONCHC6H4O)2] 933.95  Click
Cu 2p3/2 CuCl2 934.00  Click
Cu 2p3/2 CuCl2 934.00  Click
Cu 2p3/2 CuO 934.00  Click
Cu 2p3/2 CuO 934.00  Click
Cu 2p3/2 CuMoO4 934.10  Click
Cu 2p3/2 Cu3Mo2O9 934.10  Click
Cu 2p3/2 CuO 934.10  Click
Cu 2p3/2 [(CH3)2NC6H3NSC6H3N(CH3)2]2[Cu(NCC(S)C(S)CN)2] 934.10  Click
Cu 2p3/2 [N(C4H9)4]2[Cu((-CC(O)C(S)C(S)C(O)-)C(CN)2)2] 934.10  Click
Cu 2p3/2 O2/Cu/NiO/Ni 934.10  Click
Cu 2p3/2 CuBr2 934.20  Click
Cu 2p3/2 CuBr2 934.20  Click
Cu 2p3/2 CuO 934.20  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 934.20  Click
Cu 2p3/2 Cu/HS(CH2)11CN/Au 934.23  Click
Cu 2p3/2 CuCl2 934.40  Click
Cu 2p3/2 Cu(OH)2 934.40  Click
Cu 2p3/2 CuRh2O4 934.40  Click
Cu 2p3/2 CuO 934.40  Click
Cu 2p3/2 K2[Cu(HNC(O)NHC(O)NH)2] 934.50  Click
Cu 2p3/2 K2[Cu(HNC(O)NHC(O)NH)2].2H20 934.50  Click
Cu 2p3/2 [Cu(CH3C(O)CHC(O)CH3)2] 934.50  Click
Cu 2p3/2 CuCr2O4 934.60  Click
Cu 2p3/2 CuO 934.60  Click
Cu 2p3/2 [N(C4H9)4]2[Cu(-CC(O)CC(S)C(S)-)2] 934.60  Click
Cu 2p3/2 YBa2Cu3O7 934.60  Click
Cu 2p3/2 Cu2CO3(OH)2 934.60  Click
Cu 2p3/2 Al2CuO4 934.70  Click
Cu 2p3/2 Cu(OH)2 934.70  Click
Cu 2p3/2 [Cu(C2O4)2(P(C6H5)4)2] 934.80  Click
Cu 2p3/2 CuCl2 934.80  Click
Cu 2p3/2 CuBr2 934.80  Click
Cu 2p3/2 CuBr2 934.80  Click
Cu 2p3/2 CuBr2 934.80  Click
Cu 2p3/2 CuBr2 934.80  Click
Cu 2p3/2 [N(C4H9)4]2[Cu(NCC(S)C(S)CN)2] 934.80  Click
Cu 2p3/2 CuMn2O4 934.80  Click
Cu 2p3/2 [Cu(-C-6H5N3)] 934.90  Click
Cu 2p3/2 CuSiO3 934.90  Click
Cu 2p3/2 CuSO4 934.90  Click
Cu 2p3/2 CuSO4 934.90  Click
Cu 2p3/2 [N(C4H9)4]2[Cu(-C(S)C(S)C(O)C(O)-)2] 934.90  Click
Cu 2p3/2 CuCO3 935.00  Click
Cu 2p3/2 [Cu(C9H6NO)2] 935.00  Click
Cu 2p3/2 Cu3(SO4)(OH)4 935.00  Click
Cu 2p3/2 Cu(C2H3O2)2 935.00  Click
Cu 2p3/2 Al2CuO4 935.00  Click
Cu 2p3/2 CuCr2O4 935.00  Click
Cu 2p3/2 CuS 935.00  Click
Cu 2p3/2 Cu(OH)2 935.10  Click
Cu 2p3/2 CuCl2 935.10  Click
Cu 2p3/2 [Cu((C6H5)2P(O)SC6H5)2](ClO4)2 935.20  Click
Cu 2p3/2 CuCl2 935.20  Click
Cu 2p3/2 Cu(UO2)2(PO4)2.8H2O 935.20  Click
Cu 2p3/2 CuSiO2(OH)2 935.20  Click
Cu 2p3/2 [N(CH3)4]2[Cu(NCC(S)C(S)CN)2] 935.20  Click
Cu 2p3/2 [Cu((C6H5)2P(O)SC2H5)2](ClO4)2 935.40  Click
Cu 2p3/2 CuSiO3.2H2O 935.40  Click
Cu 2p3/2 C32H16CuN8 935.40  Click
Cu 2p3/2 K[Cu(HNC(O)NHC(O)NH)2] 935.50  Click
Cu 2p3/2 [Cu(C6H5O)2(C(CN)H2C(CN)H2)] 935.50  Click
Cu 2p3/2 Cu(NO3)2 935.50  Click
Cu 2p3/2 CuSO4 935.50  Click
Cu 2p3/2 CuCl2 935.60  Click
Cu 2p3/2 CuCl2 935.60  Click
Cu 2p3/2 CuSO4.nH2O 935.60  Click
Cu 2p3/2 YBa2Cu3O7 935.70  Click
Cu 2p3/2 [Cu(H2NC(O)NHC(O)NH2)2]Cl2 935.80  Click
Cu 2p3/2 CuF2 936.00  Click
Cu 2p3/2 CuF2 936.00  Click
Cu 2p3/2 CuF2 936.00  Click
Cu 2p3/2 CuF2 936.00  Click
Cu 2p3/2 CuSO4 936.00  Click
Cu 2p3/2 CuF2 936.10  Click
Cu 2p3/2 CuF2 936.10  Click
Cu 2p3/2 CuF2 936.50  Click
Cu 2p3/2 CuF2 936.50  Click
Cu 2p3/2 CuF2 936.80  Click
Cu 2p3/2 CuF2 936.80  Click
Cu 2p3/2 CuF2 937.00  Click
Cu 2p3/2 CuF2 937.00  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 Copper Materials

 

 

 

Expert Knowledge Explanations

→  Periodic Table 

 

Copper Chemical Compounds

 

Peak-fits and Overlays of Chemical State Spectra

Pure Copper (Cuo):  Cu (2p)
Cu (2p3/2) BE = 932.6 eV		 CuO:  Cu (2p)
C (1s) BE = 285.0 eV		 CuF2:  Cu (2p)
C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Overlay of Cu (2p) Spectra shown Above

C (1s) BE = 285.0 eV

 

 

Chemical Shift between Cu and CuO: xx eV
 Chemical Shift between Cu and Cu2O3:  xx eV

 

→  Periodic Table 

 

Copper Oxide (CuO)
pressed powder

Survey Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
 Cu (2p3/2) Chemical State Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
O (1s) Chemical State Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
 C (1s) Chemical State Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
Cu (3s) Chemical State Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
 Cu (3p) Chemical State Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
Valence Band Spectrum from CuO
Flood gun is ON, C (1s) BE = 285.0 eV
 Auger Signals from CuO
Flood gun is ON, C (1s) BE = 285.0 eV


Shake-up Features
in CuO

Cu (2p3/2) in Cuo Cu (2p3/2) in CuO

 

 

Multiplet Splitting Features for
Copper Compounds

Cu metal – NO Splitting for Cu (3s) CuO Compound – Multiplet Splitting Peaks for Cu (3s)

.
Cu2O – Multiplet Splitting for Cu (3s) CuF2 Compound – Multiplet Splitting Peaks for Cu (3s)

 

Overlay of
“3s” Spectra for Cu, Cu2O, CuO, and CuF2

Multiplet Splitting Comparison

 

 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

 

Copper Chemical Compounds

 

Cupric Fluoride, CuF2

 

   
Survey Spectrum from CuF2  (pressed powder)
This survey was run at Start, so this survey has least degradation, but still the F atom% is low.
Cu (2p) signals were peak-fit – shown below

 

 

 
Survey Spectrum from CuF2
Flood gun is ON, C (1s) BE = 285.0 eV
This survey was run at the start, so degradation is minimum		 Cu (2p3/2) Chemical State Spectrum from CuF2
The large FWHM is due to the use of a large pass energy used in survey
This peak-fit represents the true peaks in CuF2 as much as possible
This survey data was run at the start, so degradation is minimum
  . 
Cu (2p) Chemical State Spectrum from CuF2
Significant degradation is present – loss of Fluorine.  Compare to the above spectrum.
This data was collected ~30 minutes later after significant degradation had occurred		 C (1s) Chemical State Spectrum from CuF2
Spectrum suffers from significant degradation – loss of Fluorine
   
Multiplet Splitting of Cu (3s)
Cu (3s) Chemical State Spectrum from CuF2
Spectrum suffers from significant degradation – loss of Fluorine		 Cu (3p) Chemical State Spectrum from CuF2
Spectrum suffers from significant degradation – loss of Fluorine
  . 
Valence Band Spectrum from CuF2
Spectrum suffers from significant degradation – loss of Fluorine		 Auger Signals from CuF2
Spectrum suffers from significant degradation – loss of Fluorine

→  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 Copper – CuO

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 

 

 

 

Flood Gun Effect on Native Oxide of Copper

 

Native Oxide of Copper Sheet – Sample GROUNDED
versus
Native Oxide of Copper Sheet – Sample FLOATING

 

 

Native Oxide of Copper Sheet – Sample Grounded

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

Cu (2p3/2) O (1s) C (1s)
     
→  Periodic Table     

 

Native Oxide of Copper Sheet – Sample Floating

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

Cu (2p3/2) O (1s) C (1s)
     
→  Periodic Table     

→  Peri

 

 

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

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.
 
 
 
Cu (2p) Signal
  O (1s) Signal C (1s) Signal
     
 
 
Copyright ©:  The XPS Library
 

 

AES Study of UHV Gas Captured by Freshly Ion Etched Copper

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

Cu (LMM) Signal:
Cu at front -> CuOx X at rear
Cu KE = 913.6 eV		 O (KLL) Signal:
Cu at front -> CuOx X at rear
O KE = 508 eV		 C (KLL) Signal:
Cu at front -> CuOx at rear 
C KE = 265.3 eV

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

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Chemical State Spectra from:
Slow Depth Profile of Cu Native Oxide by AES

Native Cu Oxide on Cu ribbon was slowly ion etched using High Energy Resolution conditions to measure Chemical States by Auger

Cu (LMM)
Cu KE = 918.2 eV    CuOx KE = 916.4 eV		 C (KLL)
C KE = 264 eV
   

 

 

 

Copper Alloys

   
XxCu XxCu
→  Periodic Table   
XxCu XxCu

 

Copyright ©:  The XPS Library 

 

 

XPS Facts, Guidance & Information

→  Periodic Table 

    Element   Copper (Cu)
  
    Primary XPS peak used for Peak-fitting:   Cu (2p3/2)  
    Spin-Orbit (S-O) splitting for Primary Peak:   Spin-Orbit splitting for “p” orbital, ΔBE = 20.0eV
  
    Binding Energy (BE) of Primary XPS Signal:   932.6 eV
  
    Scofield Cross-Section (σ) Value:   Cu (2p3/2) =16.73        Cu (2p1/2) = 8.66
  
    Conductivity:   Cu resistivity =  
Native Oxide suffers Differential Charing		  
    Range of Cu (2p) Chemical State BEs:   931 – 936 eV range   (Cuo to CuF2)  
    Signals from other elements that overlap
Cu (2p) 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 Cu (2p)

  • FWHM (eV) of Cu (2p3/2) from Pure Cuo :  ~0.92 eV using 50 eV Pass Energy after ion etching:
  • FWHM (eV) of Cu (2p3/2) from Cu2O xtal:  ~1.2 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  932.6 eV for Cu (2p3/2) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for Cu (2p):  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 Copper

  • Copper develops a thick native oxide due to the reactive nature of clean Copper .
  • The native oxide of CuOx is 1-2 nm thick.
  • Copper thin films often have a low level of iron (Fe) in the bulk as a contaminant or to strengthen the thin film
  • Copper 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 Cu (2p) peak as well as Cu (3p) and Cu (Auger).
  • 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 Copper (Cu)

  • Conductivity:  Copper 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:  Cu (2p3) at 932.6  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:  920 – 950 eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  920 – 1020 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

  • 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
 
from the Thermo-Scientific Website
 

Interpretation of XPS spectra

  • Cu2p peak has significantly split spin-orbit components (Δ=19.75eV, intensity ratio=0.508)
    • Possible to distinguish Cu oxidation states using satellite features of Cu2p.
    • Cu (II) has observable collection of satellite features 943eV.
    • Cu2p3/2 peak in Cu (II) oxide is shifted and is much broader compared to Cu (I) oxide.

In Cu (I) oxide, there is only a very weak satellite at 945eV.
Cu2p3/2 peak in Cu (I) oxide is NOT shifted but is broader compared to Cu metal.

  • Several Copper BEs from compounds have small binding energy shifts compared to copper metal, so we often analyze the Cu Auger peak BEs
    • Collect principal Cu LMM peak as well as Cu2p. Bigger chemical shifts observed for Cu LMM compared to Cu2p.
    • Use Wagner plot to help assign chemistry.

End of File