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


Selenium (Se)

 

Cobaltomenite – CoSeO3-3H2O  Selenium – Seo Chalcomenite – CuSeO3-2H2O

 

  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 Se 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


Selenium (Seo) Non-metal

Peak-fits, BEs, FWHMs, and Peak Labels

.
Selenium (Seo)
Se (3d) Spectrum – raw spectrum
ion etched clean		 Selenium (Seo)
Peak-fit of Se (3d) Spectrum
(w/o asymm)
→  Periodic Table – HomePage  
Selenium (Seo)
Se (3d) Spectrum – extended range 
 Selenium (Seo)
Alternate Peak-fit of Se (3d) Spectrum – assumes 2 species 
   
 

Survey Spectrum of Selenium (Seo)

with Peaks Integrated, Assigned and Labelled

 
→  Periodic Table 

XPS Signals for Selenium, (Seo) 

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
Mo (3d) and S (2s) overlap Se (3s) 230 1.43 25.5
S (2p) overlaps Se (3p1/2) 167 1.55 26.5
S (2p) overlaps Se (3p3/2) 162 2.98 26.5
Li (1s) and Fe (3p) overlap Se (3d3/2) 55.70 2.29 28.2
Li (1s) and Fe (3p) overlap Se (3d5/2) 54.84 2.29 28.2
Se (4p) 6 0.210 xxx

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

Plasmon Peaks

Energy Loss Peaks

Auger Peaks

Energy Loss    Intrinsic Plasmon Peak:  ~xx eV above peak max
Expected Bandgap for PbSe:  1.0-1.5 eV  (https://materialsproject.org/)
Work Function for Se:  xx eV

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

→  Periodic Table 

 

Valence Band Spectrum from Selenium, Seo 
 Fresh exposed bulk produced by scraping bead in lab air

 

 

Plasmon Peaks from Selenium, Seo 
 Fresh exposed bulk produced by scraping bead in lab air

Se (3d) – Extended Range Spectrum Se (3d) – Extended Range Spectrum – Vertically Zoomed
→  Periodic Table 
 

Se (LMM) Auger Peaks from Seo 
 Fresh exposed bulk produced by extensive Ar+ ion etching
Seo – main Auger peak Seo – full Auger range

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 
 

Artefacts Caused by Argon Ion Etching

C (1s) from Carbide(s)

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

Argon Trapped in Seo

can form when Argon Ions are used
to removed surface contamination
 

Side-by-Side Comparison of
Lead Selenide (PbSe) Surfaces
Exposed Bulk compared to Native Oxide

Peak-fits, BEs, FWHMs, and Peak Labels
PbSe crystal – freshly exposed bulk PbSe crystal – old native oxide
Se (3d) from fresh PbSe
Flood Gun OFF
As-Measured		 Se (3d) from old PbSe
Flood Gun OFF
As-Measured, C (1s) at 284.7 eV
  .
PbSe crystal – freshly exposed bulk PbSe crystal – old native oxide
C (1s) from freshly exposed bulk of PbSe
As-Measured,  (Flood Gun OFF)

C (1s) from old native oxide of PbSe
As-Measured, C (1s) at 284.7 eV, Flood Gun OFF
→  Periodic Table 
  . 
PbSe crystal – freshly exposed bulk PbSe crystal – old native oxide
O (1s) from freshly exposed bulk of PbSe
As-Measured, (Flood Gun OFF)

O (1s) from old native oxide of PbSe
As-Measured, C (1s) at 284.7 eV, Flood Gun OFF
→  Periodic Table

 

 

Survey Spectrum of Lead Selenide, PbSe
(fresh exposed bulk)
with Peaks Integrated, Assigned and Labelled

 

→  Periodic Table 

 

 

Survey Spectrum of Lead Selenide, PbSe
(old native oxide)

with Peaks Integrated, Assigned and Labelled

Overlays of Se (3d) Spectra for
Seo, PbSe (fresh) and PbSe (old native oxide)

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

 Overlay of Seo and PbSe (fresh bulk) – Se (3d)
Native Oxide C (1s) = 284.7 eV (Flood gun OFF)
Chemical Shift: -1.9 eV		  Overlay of Seo and PbSe old Native oxide – Se (3d)
Pure Oxide C (1s) = 285.0 eV
Chemical Shift: +3.5 eV (Se and PbSeOx)
→  Periodic Table  Copyright ©:  The XPS Library 

 

Overlay of Se (3d)
Seo, PbSe (fresh bulk), & PbSe (old native oxide):   

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Valence Band Spectra
Seo, PbSe (fresh exposed bulk)

Seo
Ion etched clean		 PbSe (fresh exposed bulk)
Flood gun is ON,  Charge referenced so C (1s) = 285.0 eV

Overlay of Valence Band Spectra
for Seo and PbSe (fresh bulk)

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Selenium Minerals, Gemstones, and Chemical Compounds

 
Laphamite – As2Se3 Athabascaite – Cu5Se4 Weibullite – Pb5Bi8Se7S11 Cadmoselite – CdSe

→  Periodic Table 

 

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

Se (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
Se 34 Pb-Se 53.2 eV 285.0 eV The XPS Library
Se 34 Cd-Se (N*1) 54.1 eV 284.8 eV Avg BE – NIST
Se 34 CuInSe2Ox (N*2) 54.9 eV 55.7 eV 284.8 eV Avg BE – NIST
Se 34 Cd-Se 54.0 eV 285.0 eV The XPS Library
Se 34 Se-Ga 54.0 eV 285.0 eV The XPS Library
Se 34 Zn-Se 54.1 eV 285.0 eV The XPS Library
Se 34 ZnSe (N*1) 54.1 eV 284.8 eV Avg BE – NIST
Se 34 Cu-Se 54.3 eV 285.0 eV The XPS Library
Se 34 Se-Ge 54.4 eV 285.0 eV The XPS Library
Se 34 Ge-Se2 54.7 eV 55.7 eV 285.0 eV The XPS Library
Se 34 In-2Se3 54.7 eV 285.0 eV The XPS Library
Se 34 Se – element 54.8 eV   285.0 eV The XPS Library
Se 34 Se3P4 (N*3) 55.4 eV 56.7 eV 284.8 eV Avg BE – NIST
Se 34 Pb-SeO4 58.3 eV 285.0 eV The XPS Library
Se 34 Ge-Se2 (N*1) 60.3 eV 284.8 eV Avg BE – NIST
Se 34 Se- 285.0 eV The XPS Library
Se 34 Se- 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

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

C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Ulvac-PHI

 

Table #3

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

C (1s) BE = 284.8 eV

Chemical state Binding energy (eV), Se (3d5/2)
Selenium 55.1

→  Periodic Table 

Copyright ©:  Thermo Scientific 

 

Table #4

Se (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

Se (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
Se 3d5/2 GeSe2 54.5 ±0.3 54.2 ～ 54.8
Se 3d5/2 Selenides 54.5 ±0.5 54.0 ～ 55.0
Se 3d5/2 Ga2Se3 54.6 ±0.3 54.3 ～ 54.9
Se 3d5/2 GeSe 54.7 ±0.3 54.4 ～ 55.0
Se 3d5/2 As2Se3 55.0 ±0.3 54.7 ～ 55.3
Se 3d5/2 Se 55.3 ±0.2 55.1 ～ 55.5
Se 3d5/2 (BrC6H4)2Se2 56.0 ±0.3 55.7 ～ 56.2
Se 3d5/2 C14H29Se)2 56.1 ±0.3 55.8 ～ 56.3
Se 3d5/2 (C4H8COOH)2SeO 58.5 ±0.3 58.2 ～ 58.8
Se 3d5/2 SeO2 59.4 ±0.5 58.9 ～ 59.8
Se 3d5/2 H2SeO3 59.6 ±0.4 59.2 ～ 59.9

→  Periodic Table 

 

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

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

Histogram indicates:  55.4 eV for Seo based on 23 literature BEs Histogram indicates:  59.4 eV for SeO2 based on 5 literature BEs

 
Histogram indicates:  54.3 eV for CuInSe2 based on 14 literature BEs Histogram indicates:  55.1 eV for CuInSe2 based on 15 literature BEs

Table #6


NIST Database of Se (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
Se 3d5/2 CdSe/GaSb 52.51  Click
Se 3d5/2 ZnSe 52.73  Click
Se 3d5/2 PbSe 53.40  Click
Se 3d5/2 In2Se3 53.40  Click
Se 3d5/2 In6Se7 53.50  Click
Se 3d5/2 InSe 53.50  Click
Se 3d5/2 CuInSe2 53.50  Click
Se 3d5/2 CuInSe2 53.50  Click
Se 3d5/2 [Pd(P(C6H5)3)2(SeP(C6H5)2)2] 53.70  Click
Se 3d5/2 NbSe2 53.70  Click
Se 3d5/2 Bi2Se3 53.70  Click
Se 3d5/2 SnSe 53.70  Click
Se 3d5/2 Au/CuInSe2 53.70  Click
Se 3d5/2 CuInSe2 53.80  Click
Se 3d5/2 Ag2Se 53.80  Click
Se 3d5/2 (GeSe2)60(Tl2Se)40 53.80  Click
Se 3d5/2 Au/CuInSe2 53.80  Click
Se 3d5/2 W6Se8(C5H5N)6 53.80  Click
Se 3d5/2 Hg0.86Mn0.14Se 53.88  Click
Se 3d5/2 HgSe 53.88  Click
Se 3d5/2 CdSe0.65Te0.35 53.90  Click
Se 3d5/2 Cu2Se 53.90  Click
Se 3d5/2 Cu90Se10 53.90  Click
Se 3d5/2 CrSe 53.90  Click
Se 3d5/2 W6Se8(C5H11N)6 53.90  Click
Se 3d5/2 Hg0.87Fe0.13Se 53.98  Click
Se 3d5/2 CuInSe2 54.00  Click
Se 3d5/2 CdSe 54.00  Click
Se 3d5/2 [N(CH3)4]2[CoSe(CN)4] 54.10  Click
Se 3d5/2 Bi2Se3 54.10  Click
Se 3d5/2 PbSe 54.10  Click
Se 3d5/2 CuInSe2Ox 54.10  Click
Se 3d5/2 Mo/CuInSe2 54.20  Click
Se 3d5/2 In2Se3 54.20  Click
Se 3d5/2 GeSe 54.30  Click
Se 3d5/2 [PSe(C6H5)3] 54.30  Click
Se 3d5/2 In2Se3 54.30  Click
Se 3d5/2 Ge0.50Se0.50 54.30  Click
Se 3d5/2 CuInSe2 54.33  Click
Se 3d5/2 CuInSe2 54.33  Click
Se 3d5/2 Bi15.6Ge20.1Se64.3 54.40  Click
Se 3d5/2 (GeSe2)70(Tl2Se)30 54.40  Click
Se 3d5/2 CuInSe2 54.40  Click
Se 3d5/2 CuInSe2 54.40  Click
Se 3d5/2 CuInSe2 54.40  Click
Se 3d5/2 CuInSe2 54.40  Click
Se 3d5/2 CuInSSe 54.40  Click
Se 3d5/2 [PH(C6H5)2]Se 54.50  Click
Se 3d5/2 Ga2Se3 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 ZnSe 54.50  Click
Se 3d5/2 Bi10.3Ge23.9Se65.8 54.50  Click
Se 3d5/2 P4Se3 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 GeSe2 54.50  Click
Se 3d5/2 WSe2 54.50  Click
Se 3d5/2 WSe2 54.50  Click
Se 3d5/2 Ge0.33Se0.67 54.50  Click
Se 3d5/2 CuGa5Se8 54.50  Click
Se 3d5/2 CoSe 54.60  Click
Se 3d5/2 Ga2Se3 54.60  Click
Se 3d5/2 Ag9GaSe6 54.60  Click
Se 3d5/2 MnSe 54.60  Click
Se 3d5/2 Bi6.5Ge25.2Se68.3 54.60  Click
Se 3d5/2 P4Se3 54.60  Click
Se 3d5/2 Ge0.43Se0.57 54.60  Click
Se 3d5/2 Ge0.27Se0.73 54.60  Click
Se 3d5/2 CuIn3Se5 54.60  Click
Se 3d5/2 Ge0.23Se0.77 54.60  Click
Se 3d5/2 Se 54.64  Click
Se 3d5/2 Se 54.64  Click
Se 3d5/2 CoSe 54.70  Click
Se 3d5/2 AgGaSe2 54.70  Click
Se 3d5/2 Ge2Se3 54.70  Click
Se 3d5/2 GeSe2 54.70  Click
Se 3d5/2 Se 54.70  Click
Se 3d5/2 Se 54.70  Click
Se 3d5/2 CdSe 54.70  Click
Se 3d5/2 ZnSe 54.70  Click
Se 3d5/2 Bi1.1Ge28.0Se70.9 54.70  Click
Se 3d5/2 Ge28.8Se71.2 54.70  Click
Se 3d5/2 (CH3)2NC(Se)Se3C(Se)N(CH3)2 54.70  Click
Se 3d5/2 CuInSe2 54.70  Click
Se 3d5/2 CuInSe2 54.70  Click
Se 3d5/2 CoSe 54.80  Click
Se 3d5/2 GeSe 54.80  Click
Se 3d5/2 GeSe3 54.80  Click
Se 3d5/2 SeC(NH2)2 54.80  Click
Se 3d5/2 In2Se3 54.80  Click
Se 3d5/2 As2Se3 54.90  Click
Se 3d5/2 As2Se3 54.90  Click
Se 3d5/2 As2Se3 54.90  Click
Se 3d5/2 Ga2Se3 54.90  Click
Se 3d5/2 GeSe2 54.90  Click
Se 3d5/2 NiSe 54.90  Click
Se 3d5/2 Se 54.90  Click
Se 3d5/2 Se 54.90  Click
Se 3d5/2 Nb3Se4 54.90  Click
Se 3d5/2 CuInSe2Ox 54.90  Click
Se 3d5/2 (GeSe2)60(Tl2Se)40 54.90  Click
Se 3d5/2 As2Se3 55.00  Click
Se 3d5/2 SnSe 55.00  Click
Se 3d5/2 TiSe 55.00  Click
Se 3d5/2 C15Se85 55.00  Click
Se 3d5/2 CuInSe2 55.00  Click
Se 3d5/2 CuInSe2 55.00  Click
Se 3d5/2 Ge0.20Se0.80 55.00  Click
Se 3d5/2 Se 55.10  Click
Se 3d5/2 VSe2 55.10  Click
Se 3d5/2 Se 55.20  Click
Se 3d5/2 Se 55.20  Click
Se 3d5/2 Se 55.20  Click
Se 3d5/2 Ni[Se2CN(CH3)2]2 55.20  Click
Se 3d5/2 (CH3)2NC(Se)SeC(Se)N(CH3)2 55.20  Click
Se 3d5/2 As2Se3 55.30  Click
Se 3d5/2 As2Se3 55.30  Click
Se 3d5/2 GeSe2 55.30  Click
Se 3d5/2 GeSe2 55.30  Click
Se 3d5/2 GeSe2 55.30  Click
Se 3d5/2 GeSe2 55.30  Click
Se 3d5/2 USe 55.39  Click
Se 3d5/2 ((-CSeC(CH3)C(CH3)Se-)2)2.BF4 55.40  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 Se 55.50  Click
Se 3d5/2 ((-CSeC(CH3)C(CH3)Se-)2)2ClO4 55.60  Click
Se 3d5/2 Ge20Se80 55.60  Click
Se 3d5/2 Se 55.60  Click
Se 3d5/2 (GeSe2)70(Tl2Se)30 55.60  Click
Se 3d5/2 Se 55.64  Click
Se 3d5/2 Se 55.70  Click
Se 3d5/2 [Se(C6H5)2] 55.80  Click
Se 3d5/2 [Se2(C6H5)2] 55.80  Click
Se 3d5/2 FeSe 55.80  Click
Se 3d5/2 P4Se3 55.80  Click
Se 3d5/2 (CH3)2NC(Se)Se3C(Se)N(CH3)2 55.80  Click
Se 3d5/2 (-CSeC(CH3)C(CH3)Se-)2 55.90  Click
Se 3d5/2 [SeS(C6H5)2] 55.90  Click
Se 3d5/2 Se 55.90  Click
Se 3d5/2 As2Se3 56.00  Click
Se 3d5/2 (C6H4SSe)n 56.00  Click
Se 3d5/2 (-CSeC(CH3)C(CH3)Se-)2 56.04  Click
Se 3d5/2 C14H29SeSeC14H29 56.10  Click
Se 3d5/2 P4Se3 56.10  Click
Se 3d5/2 [Se(SC2H4OH)2] 56.20  Click
Se 3d5/2 (-COC(S)N(C2H5)C(O)-)C(C2H5)CH(-CSe(C6H4)N(CH3)-) 56.20  Click
Se 3d5/2 (-C(O)C(CH2OC16H33)CHC(NO2)CHC-)CHCH(-CSe(C6H4)N(CH3)-) 56.20  Click
Se 3d5/2 ((-CSeC(CH3)C(CH3)Se-)2)2ReO4 56.23  Click
Se 3d5/2 ((-CSeC(CH3)C(CH3)Se-)2)2ClO4 56.29  Click
Se 3d5/2 ((-CSeC(CH3)C(CH3)Se-)2)2NO3 56.29  Click
Se 3d5/2 [Se(C6H4Br)2] 56.40  Click
Se 3d5/2 (-CSC(S)NHC(O)-)C(C2H5)CH(-CSe(C6H4)N(CH3)-) 56.40  Click
Se 3d5/2 (GeSe2)80(Tl2Se)20 56.40  Click
Se 3d5/2 Se 56.70  Click
Se 3d5/2 (CH3)2NC(Se)SeC(Se)N(CH3)2 56.70  Click
Se 3d5/2 Na2Se(S2O3)2 56.90  Click
Se 3d5/2 Se 57.50  Click
Se 3d5/2 [SeO(C6H5)2] 57.60  Click
Se 3d5/2 [SeCl2(C6H5)2] 57.70  Click
Se 3d5/2 [NCSeC16H33] 57.70  Click
Se 3d5/2 (GeSe2)80(Tl2Se)20 57.70  Click
Se 3d5/2 [Se(C6H5)2]Br2 57.80  Click
Se 3d5/2 [Se(C6H5)2]I2 58.10  Click
Se 3d5/2 (GeSe2)90(Tl2Se)10 58.10  Click
Se 3d5/2 [SeO(C6H4CH3)2] 58.20  Click
Se 3d5/2 [SeO(C6H4Br)2] 58.40  Click
Se 3d5/2 [SeO(C4H8COOH)2] 58.50  Click
Se 3d5/2 [SeCl2(C6H5)2] 58.80  Click
Se 3d5/2 [C6H5Se(O)OH] 58.80  Click
Se 3d5/2 SeO2 58.80  Click
Se 3d5/2 SeO2 58.80  Click
Se 3d5/2 H2SeO3 59.00  Click
Se 3d5/2 Na2SeO3 59.10  Click
Se 3d5/2 [SeI3C6H5] 59.30  Click
Se 3d5/2 [ClC6H4Se(O)OH] 59.30  Click
Se 3d5/2 GeSe2 59.40  Click
Se 3d5/2 (GeSe2)90(Tl2Se)10 59.50  Click
Se 3d5/2 SeO2 59.80  Click
Se 3d5/2 H2SeO3 59.90  Click
Se 3d5/2 SeO2 59.90  Click
Se 3d5/2 SeO2 59.90  Click
Se 3d5/2 [SeO2(C6H4OCH3)2] 60.00  Click
Se 3d5/2 ClC6H4SeO2(OH) 60.20  Click
Se 3d5/2 H2SeO4 61.00  Click
Se 3d5/2 Na2SeO4 61.60  Click

 

Statistical Analysis of Binding Energies in NIST XPS Database of BEs

 

 

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Advanced XPS Information Section

Expert Knowledge, Spectra, Features, Guidance and Cautions  

for XPS Research Studies on Selenium Materials

 

 

Expert Knowledge Explanations

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Selenium Chemical Compounds

 

Peak-fits and Overlays of Chemical State Spectra

Pure Selenium:  Se (3d)
Cu (2p3/2) BE = 932.6 eV		 PbSe (bulk):  Se (3d)
C (1s) BE = 284.7 eV		 PbSeO4:  Se (3d)
C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

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Overlay of Se (3d) Spectra shown Above

C (1s) BE = 285.0 eV

 

 Chemical Shift between PbSe and PbSeO4:  6 eV

 

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PbSe (fresh exposed bulk)
crystal

Survey Spectrum from Fresh PbSe
Flood gun is OFF, Sample is conductive		 Se (3d) Chemical State Spectrum from Fresh PbSe
Flood gun is OFF, Sample is conductive
  . 
Pb (4f) Chemical State from Fresh PbSe
Flood gun is OFF, Sample is conductive		 C (1s) Chemical State Spectrum from Fresh PbSe
Flood gun is OFF, Sample is conductive
  .
Valence Band Spectrum from Fresh PbSe
Flood gun is OFF, Sample is conductive

 

Features Observed

  • xx
  • xx
  • xx

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Selenium Chemical Compounds

 

Lead Selenate, PbSeO4

Survey Spectrum Se (3d) Spectrum
.
C (1s) Spectrum Pb (4f) Spectrum
.
Valence Band Spectrum O (1s) Spectrum

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Selenium Chemical Compounds

 

Zinc Selenide, ZnSe
single crystal – fresh exposed bulk
sample is conductive

Survey Spectrum Se (3d) Spectrum
.
C (1s) Spectrum Zn (2p3/2) Spectrum
  .
Valence Band Spectrum

 

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 – Selenium

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 “reliaSelity” of the atom % values produced by XPS.

 

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Copyright ©:  The XPS Library

 

Alloys

   
XxCu XxCu
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XxCu XxCu

 

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XPS Facts, Guidance & Information

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    Element Selenium (Se)
  
    Primary XPS peak used for Peak-fitting: Se (3d)  
    Spin-Orbit (S-O) splitting for Primary Peak: Spin-Orbit splitting for “d” Orbital, ΔBE = 0.86 eV
  
    Binding Energy (BE) of Primary XPS Signal: 54.9 eV
  
    Scofield Cross-Section (σ) Value: Se (3d) = 2.29
  
    Conductivity: Se resistivity =  
Native Oxide suffers Differential Charing		  
    Range of Se (3d5/2) Chemical State BEs: 52 – 59 eV range   (Seo to SeF3)  
Signals from other elements that overlap
Se (3d5/2) Primary Peak:		   Li (1s), Na (2s), Fe (3p)
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 

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

  • FWHM (eV) of Se (3d5/2) for Pure Seo :  ~0.7 eV using 25 eV Pass Energy after ion etching:
  • FWHM (eV) of Se (3d5/2) for PbSeOx:  ~1.2 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  54.9 eV for Se (3d5/2) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for Se (3d5/2):  Li (1s), Na (2s), Fe (3p)

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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) = ~0.90 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
    • Ag (3d5/2) FWHM (eV) = ~0.85 eV for PE 50 on SSI S-Probe
  • 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.
  • Constraints used on Peak-fitting: typically constrain the peak area ratios based on the Scofield cross-section values
  • Asymmetry for Conductive materials:  20-30% with increased Lorentzian %
  • Peak-fitting “2s” or “3s” Peaks:  Often need to use 50-60% Lorentzian peak-shape

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

  • Selenium does not develops a thick native oxide
  • The native oxide of Se Ox is 0-1 nm thick.  SeO2 can sublime in vacuum.
  • Metal thin films often have a low level of iron (Fe) in the bulk as a contaminant or to strengthen the thin film
  • Metal 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 Se (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

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Data Collection Settings for Selenium (Se)

  • Conductivity:  Metals readily develop 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:  Se (3d5/2) at 54.7 eV
  • Recommended Pass Energy for Measuring Chemical State Spectrum: 40-60 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: 45 – 65 eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  40 – 100eV
  • Recommended BE Range for Survey Spectrum:  -10 to 1,100 eV   (above 1,100 eV there are no useful XPS signals, except for Ge, As and Ga, above 1100 is waste of time)
  • 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 Se 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

 

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

 

Chemical State Spectra from Literature
from Thermo website

End of File