Alo

Al2O3

Al(OH)3

AlO(OH)

Al2(SO4)3

Al4C3

LiAlO2

AlF3

Al6Si2O13

BeAl2O4

AlN

YAlO3

Basic

XPS Spectra
Aluminum (Al) Compounds
The XPS Spectra section provides raw and processed survey spectra, chemical state spectra, BE values, FWHM values, and overlays of key spectra.
Atom% values from surveys are based on sample, as received, and Scofield cross-sections. Atom% values are corrected for IMFP and PE.
Peak-fits are guides for practical, real-world applications. Peak-fits are not fully optimized or designed to test any theory.

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Aluminum Sulfate  (Al₂(SO₄)₃)
Survey, Peak-fits, BEs, FWHMs, and Peak Labels

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→  Periodic Table	→ Six (6) BE Tables
Survey Spectrum from Al2(SO4)3 Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag (3d5/2) FWHM = 1.3 eV
→  Periodic Table	→ Six (6) BE Tables
Al (2p) Spectrum from Al2(SO4)3 – Raw Fresh exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	Al (2p) Spectrum from Al2(SO4)3 – Peak-Fit Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
Al (2s) Spectrum from Al2(SO4)3 – Raw Fresh exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	Al (2s) Spectrum from Al2(SO4)3 – Peak-Fit Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
Al (2p-2s) Spectrum from Al2(SO4)3 – Extended Range Fresh exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	Al (2p) Spectrum from Al2(SO4)3 – Raw – Vertically Expanded Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
O (1s) Spectrum from Al2(SO4)3 – Raw Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	O (1s) Spectrum from Al2(SO4)3 – Peak-Fit Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
O (1s) Spectrum from Al2(SO4)3 – Raw – Extended Range Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	O (1s) Spectrum from Al2(SO4)3 – Raw – Vertically Expanded Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
S (2p-2s) Spectrum from Al2(SO4)3 – Raw Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	S (2p) Spectrum from Al2(SO4)3 – Peak-Fit Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
C (1s) Spectrum from Al2(SO4)3 – Raw Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	C (1s) Spectrum from Al2(SO4)3 – Peak-Fit Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV

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→  Periodic Table	→ Six (6) BE Tables
O KLL Auger Signals from Al2(SO4)3 – Raw Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	Valence Band Signals from Al2(SO4)3 – Raw Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV

Overlays
→  Periodic Table	→ Six (6) BE Tables
Valence Band Spectra – Overlay of Alo and Al2(SO4)3 Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV	Al (2p) Spectra – Overlay of Alo and Al2(SO4)3 Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table	→ Six (6) BE Tables
	Al (2p) Spectra – Overlay of Al2O3 and Al2(SO4)3 Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
End-of-spectra Price to purchase raw data sets: Raw spectra – VAMAS ASCII format ($6) Raw spectra – SDP binary format ($5) SDP v9 – $145 (3 yr license)     Transmission Function Tests

December 2015 – Transmission Function of Thermo K-Alpha Plus

→  Periodic Table

Survey Spectra of Ion Etched Copper (Cr), PEs = 50, 100, 150 and 200 eV

→  Periodic Table

March 2016 – Transmission Function of Thermo K-Alpha Plus

Survey Spectra of Ion Etched Copper (Cr), PEs = 100, 150 and 200 eV

→  Periodic Table

August 2019 – Transmission Function of Thermo K-Alpha Plus

Survey Spectra of HOPG (C), PEs = 20, 50, 100 and 200 eV

→  Periodic Table

January 2022 – Transmission Function of Thermo K-Alpha Plus

Survey Spectra of Ion Etched Copper (Cr), PEs = 100, 120, 140, 160, 180 and 200 eV

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Six (6) Chemical State Tables of Al (2p) BEs

 

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

→  Periodic Table 

 

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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 (2p_3/2) 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
• There are uncertainties and error ranges in nearly all BEs 
  • Flood guns
• 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 (2p_3/2) 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 

 

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Table #1

Al (2p) 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
Al	13	Al – element	72.9 eV		285.0	The XPS Library
Al	13	AlGaAs	74.1 eV		285.0	The XPS Library
Al	13	Al2O3 (N*3)	74.3 eV	74.7 eV	284.8	Avg BE – NIST
Al	13	Al-N	74.3 eV		285.0	The XPS Library
Al	13	Pyrope	74.4 eV		285.0	The XPS Library
Al	13	Mica	74.5 eV		285.0	The XPS Library
Al	13	Al2SiO5	74.7 eV		285.0	The XPS Library
Al	13	Al2(SO4)3 (N*1)	74.9 eV		284.8	Avg BE – NIST
Al	13	LiAlSi2O6	75.3 eV		285.0	The XPS Library
Al	13	Al2O3/Al	75.4 eV	75.9 eV	285.0	The XPS Library
Al	13	Al2O3-TiC	75.4 eV		285.0	The XPS Library
Al	13	Al2O3/Al (N*16)	75.6 eV	75.8 eV	284.8	Avg BE – NIST
Al	13	Al-OOH	75.7 eV		285.0	The XPS Library
Al	13	Al(OH)3	76.2 eV		285.0	The XPS Library
Al	13	Al-F3	77.0 eV		285.0	The XPS Library
Al	13	Al-Br3			285.0	The XPS Library
Al	13	Al2(SO4)3	76.2 eV		285.0	The XPS Library

 

 

Charge Referencing

• (N*number) identifies the number of NIST BEs that were averaged to produce the BE in the middle column.
• Binding Energy Scale Calibration expects 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 (SO) 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

Al (2p) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

Copyright ©:  Ulvac-PHI

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Table #3

Al (2p) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical State	Binding Energy – Al (2p)
Al metal	72.6 eV
Aluminosilicate	74.4 eV
Al oxide	74.6 eV
Al oxide on Al foil	75.6 eV

Copyright ©:  Thermo Scientific website

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Table #4

Al (2p) 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

Copyright ©:  Mark Beisinger

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Table #5

Al (2p) Chemical State BEs from:  “Techdb.podzone.net” Website

XPS Spectra – Chemical Shift | Binding Energy
C (1s) BE = 284.6 eV

Element	Level	Compound	B.E. (eV)		min		max
Al	2p	Al	72.8	±0.3	72.5	～	73.0
Al	2p	AlAs	73.6	±0.3	73.3	～	73.9
Al	2p	AlGaAs	73.7	±0.4	73.3	～	74.0
Al	2p	Al2O3, alpha	73.9	±0.3	73.6	～	74.2
Al	2p	Al2O3, gamma	74.0	±0.3	73.7	～	74.3
Al	2p	Al2O3, sapphire	74.2	±0.3	73.9	～	74.5
Al	2p	AlOOH, boehmite	74.3	±0.3	74.0	～	74.6
Al	2p	Oxides	74.5	±0.3	74.2	～	74.8
Al	2p	Halides	75.4	±0.9	74.5	～	76.3
Al	2p	LiAlH4	75.6	±0.4	75.2	～	76.0
Al	2p	AlF3	76.4	±0.4	76.0	～	76.7

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Statistical Analysis of Binding Energies in NIST XPS Database of BEs

 

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