Oso Native OsOx OsO2 K2OsO2(OH)4 OsCl3-H2O              

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

 

Osmium (Os)

 

Osmium tetroxide – OsO4 Osmium – Oso Potassium Osmalate – K2OsO2(OH)4

 

  Page Index
  • Expert Knowledge & Explanations


Osmium (Oso) Metal

Peak-fits, BEs, FWHMs, and Peak Labels


Osmium (Oso) Metal
Os (4f) Spectrum – raw spectrum, ion etched clean
Osmium (Oso) Metal
Peak-fit of Os (4f) Spectrum (w/o asymm)
→  Periodic Table – HomePage  
Osmium (Oso) Metal
Os (4f) Spectrum – extended range 
 Osmium (Oso) Metal
Peak-fit of Os (4f) Spectrum (w asymm)
 

 
Osmium (Oso) Metal
Os (4p) Spectrum		 Osmium (Oso) Metal
Os (4d) Spectrum

 

Survey Spectrum of Osmium (Oso) Metal
with Peaks Integrated, Assigned and Labelled

 

→  Periodic Table 

XPS Signals for Osmium (Oso) 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
  Os (4s) 658 1.86 xx.x
  Os (4p1/2) 548 2.13 xx.x
  Os (4p3/2) 470 5.45 xx.x
K (2p) & C (1s) overlap Os (4d3/2) 293 7.23 xx.x
  Os (4d5/2) 278 10.48 xx.x
Li (1s), Fe (3p), Zr (4s) overlap Os (4f5/2) 53.3 5.48 16.3
  Os (4f7/2) 50.6 6.96 16.3
  Os (5s) 84 0.422 xx.x
  Os (5p1/2) 53 0.408 xx.x
As (3d) overlaps Os (5p3/2) 44 0.928 xx.x
  Os (5d) 3 0.847 xx.x

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

Energy Loss Peaks

Auger Peaks

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

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

→  Periodic Table 

 

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

 

 

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

Os (4f) – Extended Range Spectrum Os (4f) – Extended Range Spectrum – Vertically Zoomed
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Os (MNN) Auger Peaks from Oso Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching
Oso Metal – main Auger peak Oso Metal – full Auger range
 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Artefacts Caused by Argon Ion Etching

C (1s) from Osmium Carbide(s)

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

Argon Trapped in Oso

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

 

Side-by-Side Comparison of

Os Native Oxide & Osmium Di-oxide (OsO2)
Peak-fits, BEs, FWHMs, and Peak Labels
Os Native Oxide OsO2
Os (4f) from Os Native Oxide
Flood Gun OFF
As-Measured, C (1s) at 284.7 eV 		 Os (4f) from OsO2 – pressed powder
Flood Gun OFF
Sample Conductive


→  Periodic Table   
Os Native Oxide OsO2
C (1s) from Os Native Oxide
As-Measured, C (1s) at 284.7 eV (Flood Gun OFF)

C (1s) from OsO2 – pressed powder
Flood Gun OFF, Sample Conductive

→  Periodic Table 
  
Os Native Oxide OsO2
O (1s) from Os Native Oxide
As-Measured, C (1s) at 284.7 eV
(Flood Gun OFF)

O (1s) from OsO2 – pressed powder
Flood Gun OFF
Sample Conductive
 

→  Periodic Table

 

 


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

 

→  Periodic Table 

 

 


Survey Spectrum of Osmium Di-oxide (OsO2)
with Peaks Integrated, Assigned and Labelled

 

→  Periodic Table  

 

Overlays of Os (4f) Spectra for:
Os Native Oxide and OsO2

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

 

 Overlay of Oso metal and Os Native Oxide – Os (4f)
Native Oxide C (1s) = 284.7  (Flood gun OFF)

  Overlay of Oso metal and OsO2 – Os (4f)
OsO2 is conductive
Chemical Shift: 1.2 eV

→  Periodic Table  Copyright ©:  The XPS Library 

 

Overlay of Os (4f)
Oso Metal, Os Native Oxide, & OsO2

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Valence Band Spectra
Oso, OsO2 

Oso
Ion etched clean		 OsO2 – pressed powder
Flood gun is ON,  Charge referenced so C (1s) = 285.0 eV

Overlay of Valence Band Spectra
for Oso metal and OsO2

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Osmium Minerals, Gemstones, and Chemical Compounds

 
Ammonium hexachloro-osmate – (NH4)2OsCl6 Osmium Trichloride – OsCl3-H2O Osmium metal – Oso Osmium di-Oxide – OsO2

→  Periodic Table 

 

 

Six (6) Chemical State Tables of Os (4f7/2) 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 between 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

Os (4f7/2) 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
Os 76 Os (N*4) 50.2 eV 50.7 eV 284.8 eV Avg BE – NIST
Os 76 Os – element 50.5 eV   285.0 eV The XPS Library
Os 76 Os – element 50.7 eV   284.8 eV  PHI Handbook
Os 76 Os-O2 51.9 eV   285.0 eV The XPS Library
Os 76 OsO2 (N*3) 52.0 eV 53.8 eV 284.8 eV Avg BE – NIST
Os 76 OsCl3 (N*2) 53.1 eV 53.4 eV 284.8 eV Avg BE – NIST
Os 76 Os-(OH)3 53.8 eV   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

Os (4f7/2) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Ulvac-PHI

Table #3

Os (4f7/2) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical state Binding energy (eV), Os (4f7/2)
Os metal 52

→  Periodic Table 

Copyright ©:  Thermo Scientific 

Table #4

Os (4f7/2) 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

na

→  Periodic Table 

Copyright ©:  Mark Beisinger

Table #5

Os (4f7/2) 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
Os 4f7/2 Os 50.5 ±0.3 50.2 ～ 50.7
Os 4f7/2 OsCl2(PhPMe2)4trans 50.6 ±0.3 50.3 ～ 50.8
Os 4f7/2 OsCl3(PhPMe2)3mer 51.8 ±0.3 51.5 ～ 52.0
Os 4f7/2 K2OsI6 52.0 ±0.3 51.7 ～ 52.2
Os 4f7/2 OsO2 52.4 ±0.4 52.0 ～ 52.8
Os 4f7/2 OsCl4(Et3P)2 52.6 ±0.3 52.3 ～ 52.8
Os 4f7/2 K2OsBr6 53.0 ±0.3 52.7 ～ 53.2
Os 4f7/2 OsCl4(PhPMe2)2trans 53.0 ±0.2 52.8 ～ 53.2
Os 4f7/2 K2OsCl6 53.5 ±0.5 53.0 ～ 53.9

 

→  Periodic Table 

 

 

Histograms of NIST BEs for Os (4f7/2) BEs

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

 

Histogram indicates:  50.6 eV for Oso based on 4 literature BEs Histogram indicates:  52.8 eV for OsO2 based on 3 literature BEs

Table #6


NIST Database of Os (4f7/2) 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
Os 4f7/2 Os 50.20  Click
Os 4f7/2 [OsCl2(P(CH3)2(C6H5))4] 50.50  Click
Os 4f7/2 ((C6H5)3P)3OsH4 50.50  Click
Os 4f7/2 Os 50.60  Click
Os 4f7/2 Os 50.66  Click
Os 4f7/2 Os 50.70  Click
Os 4f7/2 Os 50.70  Click
Os 4f7/2 [Os(NH3)5(N2)]I2 50.90  Click
Os 4f7/2 [OsCl(CO)H((C6H5)3P)3] 51.10  Click
Os 4f7/2 ((C6H5)3P)3OsHBrCO 51.10  Click
Os 4f7/2 [Os(CO)Br(P(C6H5)3)2(C5H3NOCH3)] 51.20  Click
Os 4f7/2 [((C6H5)3P)4OsH3][HC(SO2CF3)2] 51.20  Click
Os 4f7/2 [N(C4H9)4][Os(H2O)(S2O3)2(P(CH3)2C6H5)3] 51.20  Click
Os 4f7/2 ((C2H5)4N)[Os2OCH3CO2Cl5(C5H5N)4]((C2H5)4N) 51.20  Click
Os 4f7/2 [OsCl2(P(C6H5)3)2(C5H3NOCH3)] 51.30  Click
Os 4f7/2 [OsCl2(P(C6H5)3)2(C5H4NO)] 51.40  Click
Os 4f7/2 [OsBr3(CH3C6H4NN)(P(C6H5)3)2] 51.40  Click
Os 4f7/2 [(C6H5)3P=N=P(C6H5)3][H2Os4(CO)12I] 51.40  Click
Os 4f7/2 [(C6H5)3P=N=P(C6H5)3][H3Os4(CO)12] 51.40  Click
Os 4f7/2 [OsBr2(P(C6H5)3)2(C5H3NOCH3)] 51.50  Click
Os 4f7/2 [Os(CO)Cl(P(C6H5)3)2(C5H3NOCH3)] 51.50  Click
Os 4f7/2 [Os(NH3)4(N2)2]Br2 51.60  Click
Os 4f7/2 [OsBr4(P(C6H5)3)2] 51.60  Click
Os 4f7/2 [((C6H5)3P)3Os(CH3C(O)O)H2][HC(SO2CF3)2] 51.60  Click
Os 4f7/2 [OsCl3(P(CH3)2C6H5)3] 51.70  Click
Os 4f7/2 [OsBr2(P(C6H5)3)2(C5H4NO)] 51.70  Click
Os 4f7/2 Os 51.70  Click
Os 4f7/2 OsCl2(CH3C(O)CHC(O)CH3)(P(C6H5)3)2 51.70  Click
Os 4f7/2 [OsBr2(P(C6H5)3)2(C5H4NCOO)] 51.80  Click
Os 4f7/2 [H4Os4(CO)12] 51.80  Click
Os 4f7/2 Os3(CO)12 51.80  Click
Os 4f7/2 [OsBr3(NO)(P(C6H5)3)2] 51.90  Click
Os 4f7/2 [OsCl2(P(C6H5)3)2(C5H4NCOO)] 51.90  Click
Os 4f7/2 K2OsI6 51.90  Click
Os 4f7/2 [H3Os4(CO)12I] 51.90  Click
Os 4f7/2 [Os(NH3)5(N2)]Br2 52.00  Click
Os 4f7/2 OsO2 52.00  Click
Os 4f7/2 [Os(NH3)5(N2)]Cl2 52.20  Click
Os 4f7/2 Os(HSO3)2 52.20  Click
Os 4f7/2 [OsCl4(P(C2H5)3)2] 52.60  Click
Os 4f7/2 OsO2 52.70  Click
Os 4f7/2 K2[OsCl6] 52.80  Click
Os 4f7/2 K2OsBr6 52.90  Click
Os 4f7/2 [OsCl4(P(CH3)2(C6H5))2] 53.00  Click
Os 4f7/2 K2[OsCl6] 53.00  Click
Os 4f7/2 [Os2OCH3CO2Cl5(C5H5N)4] 53.00  Click
Os 4f7/2 OsCl3 53.10  Click
Os 4f7/2 K2[OsCl6] 53.20  Click
Os 4f7/2 K2[OsCl6] 53.20  Click
Os 4f7/2 K2[Os(NO)Br5] 53.30  Click
Os 4f7/2 K2[Os(NO)Cl5] 53.40  Click
Os 4f7/2 OsCl3 53.40  Click
Os 4f7/2 K2[OsCl6] 53.50  Click
Os 4f7/2 [N(C4H9)4]2[OsO2(S2O3)2(C8H20N2)] 53.60  Click
Os 4f7/2 [OsO6(C5H5N)4] 53.80  Click
Os 4f7/2 OsO2 53.80  Click
Os 4f7/2 K2[OsCl6] 53.90  Click
Os 4f7/2 [P(C6H5)4]2[OsO2(S2O3)2(C6H5N)2] 53.90  Click
Os 4f7/2 [N(C4H9)4]2[OsO2(S2O3)2] 53.90  Click
Os 4f7/2 [N(C4H9)4]2[OsO2(S2O3)2(C6H16N2)] 53.90  Click
Os 4f7/2 K2[(Os(O2)(OH)(H2O))2O2] 54.10  Click
Os 4f7/2 [OsCl2(O)2((C2H5)2P(C6H5))2] 54.10  Click
Os 4f7/2 K[(N)OsCl4(H2O)] 54.20  Click
Os 4f7/2 [OsBr2(O)2(P(C6H5)3)2] 54.20  Click
Os 4f7/2 [P(C6H5)4]2[OsO2(S2O3)2(C9H13N)2] 54.20  Click
Os 4f7/2 K4[(Os(O2)(NO2)2)2O2].6H2O 54.30  Click
Os 4f7/2 K2[OsO2(OH)4] 54.30  Click
Os 4f7/2 OsO2(C5H5N)2(C7H10O6) 54.40  Click
Os 4f7/2 OsO2(C5H5N)2(OC(C(O)O)(CH2C(O)OH)2) 54.40  Click
Os 4f7/2 OsO2(C5H5N)2(OC(O)C(O)O) 54.50  Click
Os 4f7/2 K2[OsO2(OCH2C(O)O)2] 54.70  Click
Os 4f7/2 [Os(O2)(NH3)4]I2 54.90  Click
Os 4f7/2 K2[Os(O2)(OH)4] 54.90  Click
Os 4f7/2 [Os(O2)(NH3)4]Br2 55.00  Click
Os 4f7/2 [Os(O2)(NH3)4]Cl2 55.00  Click
Os 4f7/2 K2[Os(O2)Cl4] 55.00  Click
Os 4f7/2 K2[Os(O2)(OH)4] 55.20  Click
Os 4f7/2 K2[Os(O2)(C2O4)2] 55.30  Click
Os 4f7/2 K[Os(NO3)] 56.10  Click
Os 4f7/2 KOsO3N 56.10  Click
Os 4f7/2 [OsO2Cl2(C5H5N)2] 56.40  Click
Os 4f7/2 Os2NCl5 57.10  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 Osmium Materials

 

 

 

Expert Knowledge Examples & Explanations

 

→  Periodic Table 

 

Osmium Chemical Compounds

 

Peak-fits and Overlays of Chemical State Spectra

Pure Osmium:  Os (4f)
Cu (2p3/2) BE = 932.6 eV		 OsO2:  Os (4f)
sample conductive		 OsF4:  Os (4f)
C (1s) BE = 285.0 eV
 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Overlay of Os (4f) Spectra shown Above

C (1s) BE = 285.0 eV

 

Chemical Shift between Os and OsO2:  1.2 eV

 

→  Periodic Table 

 


Osmium Oxide, OsO2
pressed powder

Survey Spectrum from OsO2
Flood Gun OFF
Sample Conductive		 Os (4f) Chemical State Spectrum from OsO2
Flood Gun OFF
Sample Conductive
  . 
O (1s) Chemical State Spectrum from OsO2
Flood Gun OFF
Sample Conductive		 C (1s) Chemical State Spectrum from OsO2
Flood Gun OFF
Sample Conductive
  . 
Valence Band Spectrum from OsO2
Flood Gun OFF
Sample Conductive		 Auger Signals from OsO2
Flood Gun OFF
Sample Conductive
na


Shake-up Features for OsO2

   
na na

 

 

Multiplet Splitting Features
 for Osmium Compounds

Os metal – NO Splitting for Os (4s) OsO2  – Splitting Peaks for Os (4s)
na na

 

 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

 

Osmium 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 Osmium – OsO2

 

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

 

 

 

Osmium Alloys

   
XxCu XxCu
→  Periodic Table   
XxCu XxCu

 

Copyright ©:  The XPS Library 

 

 


XPS Facts, Guidance & Information

→  Periodic Table 

    Element   Osmium (Os)
  
    Primary XPS peak used for Peak-fitting:   Os (4f7/2)  
    Spin-Orbit (S-O) splitting for Primary Peak:   Spin-Orbit splitting for “f” orbital,  ΔBE = 2.7 eV
  
    Binding Energy (BE) of Primary XPS Signal:   50.5 eV
  
    Scofield Cross-Section (σ) Value:   Os (4f7/2) = 6.96     Os (4f5/2) = 5.48
  
    Conductivity:   Os resistivity =  
Native Oxide suffers Differential Charing		  
    Range of Os (4f7/2) Chemical State BEs:   50 – 53 eV range   (Oso to OsF2)  
    Signals from other elements that overlap
Os (4f7/2) Primary Peak:		   Mg (2p)  
    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 Os (4f7/2)

 

  • FWHM (eV) of Os (4f7/2) for Pure Oso :  ~0.9 eV using 25 eV Pass Energy after ion etching
  • FWHM (eV) of Os (4f7/2) for OsO2:  ~1.7 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  50.5 eV for Os (4f7/2) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for Os (4f7/2):  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) = ~0.90 eV for PE 50 on Thermo K-Alpha
    • Ag (3d5/2) FWHM (eV) = ~0.95 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 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 a very few compounds are negative due to unusual electron polarization.

→  Periodic Table 

 

Contaminants Specific to Osmium

 

  • Osmium develops a native oxide due to the reactive nature of clean Osmium.
  • The native oxide of OsOx is 1-4 nm thick.
  • Osmium thin films can have a low level of iron (Fe) in the bulk as a contaminant or due to sputter coater shields
  • Osmium forms a low level of carbide when the surface is argon 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. The BE for C (1s) is a useful guide.  It is not absolute. Chemical shifts from native oxides can be erroneous.
  • Collect spectra from the valence band, and the principal Os (4f7/2) peak.  Auger peaks are sometimes used to decide chemical state assignments.
  • Long time exposures (high dose) to X-rays can degrade various polymers, catalysts, and 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 are sometimes used to discern chemical states when XPS shifts are very small. Auger shifts can be larger than XPS shifts.

→  Periodic Table 

 

Data Collection Settings for Osmium (Os)

 

  • Conductivity:  Osmium 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:  Os (4f7/2) at 51 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:  45- 65eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  40- 100 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, As, 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 Os 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 

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Gas Phase XPS or UPS Spectra
 
 
     
     
     
     
     
     
     
     
     
 
 
 
 

 

Chemical State Spectra from Literature
 
 
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