| AVS 63rd International Symposium & Exhibition | |
| Applied Surface Science | Monday Sessions |
| Session AS-MoM |
| Session: | Quantitative Surface Analysis: New Ways to Perform Old Tricks |
| Presenter: | Adam Roberts, Kratos Analytical Limited, UK |
| Authors: | A.J. Roberts, Kratos Analytical Limited, UK N. Fairley, Casa Software Ltd, UK J.D.P. Counsell, Kratos Analytical Limited, UK C.J. Blomfield, Kratos Analytical Limited, UK |
| Correspondent: | Click to Email |
Material characterisation by photoelectron spectroscopy is an established technique with a wealth of published data. With the improvement in spectrometer performance spectra are routinely acquired from areas with diameters in the tens of microns, although most routine analysis is performed at much larger areas. Spectra averaged over an analysed area assume a material is homogeneous over this probed area although this might not be true [1,2]. Information from lateral and in-depth distributions [3] for elemental and chemical states on a surface can be probed using XPS imaging either at a single binding (kinetic) energy or over a narrow energy range corresponding to a core-level photoemission peak.
A relatively new and under exploited approach for materials surface characterisation is multispectral XPS imaging, also referred to as spectromicroscopy, where a series of images incremented in energy such that each pixel contains a spectrum. A great advantage of this approach is that spectral information can be reconstructed from defined areas which are smaller than those possible with focused x-ray or virtual probe selected area XPS. Furthermore intensity may be classified by pixel location and binding energy, and summed to reveal multiple spectral forms from a measurement. These spectral forms are ideal for a novel vector method used to identify spectral components characteristic of a material [4,5]. Analysis of the spectra-from-images where the reconstructed spectra are no longer averaged over the total area from which the image is acquired is central to the success of the vector analysis approach. This allows both sample and instrument dependent differences to be ‘removed’ from the data.
Development of data processing to support spectromicroscopy data reduction has been necessary and a number of approaches have been successfully applied in the characterisation of model and real-world samples[6,7]. This approach has been extended to the interpretation of C 1s spectra for carbon based materials from purely sp2 graphite and a small number of polymeric materials. As part of this study the influence of sputter cleaning such materials using Ar+ ion gas clusters is also presented.
[1] S. Béchu et.al Surf. Interface Anal., 2016,48,301-309
[2] E.F. Smith et.al Surf. Interface Anal. 2005, 38, 69-75
[3] J. Walton, et.al Surf. Interface Anal. 2016, 48, 164–172
[4] J. Baltrusaitisa, et.al, Applied Surface Science 326 (2015) 151–161
[5] M. d’Halluin, at.al, 2015 Carbon, 93, 974 -983
[6] J. Walton, et.al, Surf. Interface Anal. 2008, 40, 478 - 481
[7] A.J. Barlow et.al, Surf. Interface Anal. 2015, 47, 173-175