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X-ray Photoelectron Spectroscopy

643 Axis Ultra DLD
Credit: Justin Gorham/NIST

Axis Ultra DLD X-ray photoelectron Spectrometer











The Material Measurement Science Division at NIST  performs surface chemical analysis using X-ray Photoelectron Spectroscopy (XPS) with capabilities for routine spectroscopy, imaging, depth profiling, angle resolved measurements and more. The POC for the XPS is Justin Gorham in the Nano Materials Research Group

Notable Applications

Distinguishing carbonaceous materials through differential charging and XPS imaging


Detecting carbon in carbon
Credit: Justin M Gorham
(Left) Model of a surface with domains of conductive carbon (MWCNTs) surrounded by relatively insulating polymer composite. (middle) XPS images of conductive carbon and charged insulating carbon.  (right)Spectra extracted from XPS images demonstrating conductive MWCNTs vs insulating composite materials at different nominal MWCNT additions.

Gorham, Osborn, et al.  Carbon 2016

Ligand photo-transformations identified using high resolution XPS spectroscopy

Hi-res XP spectra reveal photochemical transformations
Credit: Justin M Gorham
(Left) Poly(vinyl pyrollidone) coated gold nanoparticles (PVP-Au) exposed to solution conditions in the light exhibit transformed physicochemical properties.  The dark control was unchanged.  (right) XP spectra of controls and experimental samples suggests an oxidation of the PVP lactam ring to a cyclic imide.  

Louie, Gorham et al. ESNano 2017


  • 4 distinct x-ray sources:
    • Monochromatic Al Kα / Ag Lα
    • Mg Kα and Al Kα flood sources (not monochromated)
  • Surface spectroscopy 
    • Small area spectra down to nominally 15 micrometers
    • Energy resolution down to nominally 0.1 eV.
  • XPS imaging capable.
    • Three field of views from (200 x 200) μm to (800 x 800) μm with (256 x 256) pixels
    • Optimized spot size at approximately 3 μm
  • Movement on 5 axis
    • Mechanically translates in X, Y, and Z as well as tilting for angle resolved measurement
    • Comes with an azimuthal stage for rotation.
  • Ion gun ready
    • Argon ion cleaning
    • Depth profiling
    • Ion selective spectroscopy for topmost layer elemental analysis.
Created February 15, 2018, Updated November 15, 2019