Six (6) Chemical State Tables of Ge (3d_5/2) BEs

 

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

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

• Accuracy of Published BEs
  • The accuracy depends on the calibration BEs used to calibrate the energy scale of the instrument.  Cu (2p3) BE can vary from 932.2 to 932.8 eV for old publications 
  • Different authors use different BEs for the C (1s) BE of the hydrocarbons found in adventitious carbon that appears on all materials and samples.  From 284.2 to 285.3 eV
  • The accuracy depends on when the authors last checked or adjusted their energy scale to produce the expected calibration BEs
• Worldwide Differences in Energy Scale Calibrations
  • For various reasons authors still use older energy scale calibrations 
  • Some authors still adjust their energy scale so Cu (3d5/2) appears at 932.2 eV or 932.8 eV because this is what the maker taught them
  • This range causes BEs in the higher BE end to be larger than expected 
  • This variation increases significantly above 600 eV BE
• Charge Compensation
  • Samples that behave as true insulators normally require the use of a charge neutralizer (electron flood gun with or without Ar+ ions) so that the measured chemical state spectra can be produced without peak-shape distortions or sloping tails on the low BE side of the peak envelop. 
  • Floating all samples (conductive, semi-conductive, and non-conductive) and always using the electron flood gun is considered to produce more reliable BEs and is recommended.
• Charge Referencing Methods for Insulators
  • Charge referencing is a common method, but it can produce results that are less reliable.
  • When an electron flood gun is used, the BE scale will usually shift to lower BE values by 0.01 to 5.0 eV depending on your voltage setting. Normally, to correct for this flood gun induced shift, the BE of the hydrocarbon C (1s) peak maximum from adventitious carbon is used to correct for the charge induced shift.
  • The hydrocarbon peak is normally the largest peak at the lowest BE. 
  • Depending on your preference or training, the C (1s) BE assigned to this hydrocarbon peak varies from 284.8 to 285.0 eV.  Other BEs can be as low as 284.2 eV or as high as 285.3 eV
  • Native oxides that still show the pure metal can suffer differential charging that causes the C (1s) and the O (1s) and the Metal Oxide BE to be larger
  • When using the electron flood gun, the instrument operator should adjust the voltage and the XY position of the electron flood gun to produce peaks from a strong XPS signal (eg O (1s) or C (1s) having the most narrow FWHM and the lowest experimentally measured BE. 

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Table #1

Ge (3d_5/2) 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
Ga	31	GaInAs	17.5 eV	18.2 eV	285.0 eV	The XPS Library
Ga	31	GaSe	17.6 eV		285.0 eV	The XPS Library
Ga	31	Ga – element	18.6 eV		285.0 eV	The XPS Library
Ga	31	GaAs (N*16)	18.6 eV	19.7 eV	284.8 eV	Avg BE – NIST
Ga	31	GaSb	18.6 eV	19.1 eV	285.0 eV	The XPS Library
Ga	31	GaSb (N*4)	18.9 eV	19.0 eV	284.8 eV	Avg BE – NIST
Ga	31	GaAs	19.1 eV	19.7 eV	285.0 eV	The XPS Library
Ga	31	GaP (N*5)	19.2 ev	19.9 eV	284.8 eV	Avg BE – NIST
Ga	31	GaN (N*2)	19.5 eV	19.7 eV	284.8 eV	Avg BE – NIST
Ga	31	GaAlAs	19.6 eV		285.0 eV	The XPS Library
Ga	31	Ga2Se3 (N*2)	19.7 eV	19.9 eV	284.8 eV	Avg BE – NIST
Ga	31	GaP	19.7 eV	20.0 eV	285.0 eV	The XPS Library
Ga	31	GaN	20.0 eV		285.0 eV	The XPS Library
Ga	31	Ga2O3 (N*5)	20.2 eV	20.7 eV	284.8 eV	Avg BE – NIST
Ga	31	Ga-2O3	21.3 eV		285.0 eV	The XPS Library
Ga	31	Ga-(OH)3			285.0 eV	The XPS Library
Ga	31	Ga-2O			285.0 eV	The XPS Library
Ga	31	Ga-Cl3			285.0 eV	The XPS Library
Ga	31	Ga-CO3			285.0 eV	The XPS Library
Ga	31	Ga-F3			285.0 eV	The XPS Library
Ga	31	Ga-S			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 (2p_3/2) BE = 932.62 eV and Au (4f_7/2) 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)

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Table #2

Ge (3d_5/2) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

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Copyright ©:  Ulvac-PHI

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Table #3

Ge (3d_5/2) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical state	Binding energy (eV), Ge (2p3)	Binding Energy (eV), Ge (3d)
Ge elemental	1217.3	29.3
GeO	1218.0	30.9
GeO2	1220.2	32.5

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Copyright ©:  Thermo Scientific 

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Table #4

Ge (3d_5/2) 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

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Copyright ©:  Mark Beisinger

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Table #5

Ge (3d_5/2) 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 Ge 3d Ge 29.4 ±0.2 29.2 ～ 29.5 Ge 3d GeAs2 29.8 ±0.3 29.5 ～ 30.0 Ge 3d GeTe 29.8 ±0.2 29.6 ～ 30.0 Ge 3d Sulfides 29.9 ±0.5 29.4 ～ 30.4 Ge 3d GeTe3As2 30.0 ±0.3 29.7 ～ 30.2 Ge 3d GeTe2 30.1 ±0.3 29.8 ～ 30.3 Ge 3d GeS2TeAs2 30.3 ±0.3 30.0 ～ 30.5 Ge 3d GeS3As 30.4 ±0.3 30.1 ～ 30.7 Ge 3d GeSe 30.9 ±0.3 30.6 ～ 31.2 Ge 3d GeSe2 31.0 ±0.3 30.7 ～ 31.3 Ge 3d GeO2 32.5 ±0.3 32.2 ～ 32.8

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Histograms of NIST BEs for Ge (3d_5/2) BEs

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

Histogram indicates:  29.2 eV for Geo based on 11 literature BEs	Histogram indicates:  32.9 eV for GeO2 based on 7 literature BEs

Table #6

NIST Database of Ge (3d_5/2) 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.

 

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Statistical Analysis of Binding Energies in NIST XPS Database of BEs

 

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