Quantitative surface chemical‐state microscopy by x‐ray photoelectron spectroscopy

Walton, John; Fairley, Neal

doi:10.1002/sia.1654

Cited by 36 publications

(21 citation statements)

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“…Images were collected over a range covering the Ni 2p 3/2 envelope of 848 eV-870 eV at an interval of 0.2 eV, using medium magnification (400 ð 400 µm), an 80 eV pass energy, imaging aperture 2, charge neutralizer set to 1.6 A, 2.8 eV, and a dwell time of 240 s. X-ray focusing was assisted by drilling two holes into the surface of the Ni metal to produce regions of zero photoelectron counts. Our procedure is similar to that used by Barkshire et al,18,19 Prutton et al, 20 Artyushkova and Fulghum, 21,22 Walton and Fairley, 23,24 and Smith, Briggs, and Fairley. 25 The image dataset was then processed using the CasaXPS software.…”

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confidence: 92%

Structure and growth of oxides on polycrystalline nickel surfaces

Payne

Grosvenor

Biesinger

et al. 2007

Surface & Interface Analysis

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The oxidation of polycrystalline nickel (Ni) metal surfaces after exposure to oxygen gas (O 2 ) at 25 and 300°C and pressures near 130 Pa, was studied using X-ray photoelectron spectroscopy (XPS). Oxide structures involving both divalent (Ni 2+ ) and trivalent (Ni 3+ ) species could be distinguished using Ni 2p spectra, while surface adsorbed O 2 and atomic oxygen (O) species could be differentiated from bulk oxide (O 2− ) using O 1s spectra. Oxide thicknesses and distributions were determined using QUASES  , and the average oxide thickness was verified using the Strohmeier formula. The reaction kinetics for oxide films grown at 300°C followed a parabolic mechanism, with an oxide thickness of greater than 4 nm having formed after 60 min. Exposure at 25°C followed a direct logarithmic mechanism with an oxide growth rate about four to five times slower than at 300°C. Reaction of a Ni (100) single crystal under comparable conditions showed much slower reaction rates compared to polycrystalline specimens. The higher reaction rate of the polycrystalline materials is attributed to grain boundary transport of Ni cations. Oxide thickness was measured on a microscopic scale for polycrystalline Ni exposed to large doses of O 2 at 25 and 300°C. The thickness of oxide was not strongly localized on this scale. However, the QUASES  analysis suggests that there is localized growth on a nanometric scale -the result of island formation. Copyright  2007 John Wiley & Sons, Ltd.KEYWORDS: X-ray photoelectron spectroscopy; nickel; oxidation; polycrystalline surfaces INTRODUCTIONThe oxidation of nickel (Ni) metal surfaces at ambient temperatures leads to the formation of thin passive films that tend to be described best using logarithmic kinetics. 1Following passivation there is little subsequent change in oxide thickness with time. 2 The mechanism is believed to follow that which was first suggested by Mott and Cabrera. 3 Reactant oxygen molecules (O 2 ) adsorb onto the surface of the metal and decompose into atomic oxygen (O (ads)). 4 The O (ads) then bonds covalently with the Ni metal atoms at the surface, weakening their attachment to the lattice. 4 Owing to the difference in electronegativity between Ni and O, a dipole forms which allows the two atoms to exchange places.4 Such a place exchange mechanism is responsible for the formation of the first one or two monolayers of oxide only. 4 Further oxidation is driven by the formation of an electric field created by the tunneling of electrons from the Ni atoms in the metal, through the thin oxide layer, to the O (ads) sitting on the surface. 1 The presence of this electric field induces the movement of ions through the oxide leading to the formation of a thicker film.1 After the film reaches a Ł Correspondence to: Brad P. Payne, Department of Chemistry, Room G-4, Western Science Centre, The University of Western Ontario, London, ON N6A 5B7, Canada. E-mail: bpayne2@uwo.ca certain thickness, the electric field is no longer strong enough to promote ion diffusion and oxidation sto...

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confidence: 92%

Structure and growth of oxides on polycrystalline nickel surfaces

Payne

Grosvenor

Biesinger

et al. 2007

Surface & Interface Analysis

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“…[20] These methods were pioneered by Fairley and Walton in XPS imaging, and were refined and extended over the last years. [21,22 22,23] One of the strongest recent advances in parallel imaging is certainly the quantitative analysis of XPS images [24,15,25] with the advent of delay-line detectors.…”

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confidence: 99%

High‐resolution XPS spectromicroscopy

Renault

2010

Surface & Interface Analysis

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The field of XPS imaging and spectromicroscopy has recently made significant progress thanks to laboratory X-ray photoelectron emission microscopy (XPEEM), a novel, versatile parallel imaging method for which lateral resolution of core-level images in the 500 nm range, and spectromicroscopy from decanometric-size area of interest have been demonstrated (J. Electron Spectroc. Relat. Phenom. 171 (2009), 68). It uses a bright microfocussed monochromated Al Kα source and a photoelectron emission microscope (PEEM) as entrance lens of a high-transmission, aberration-compensated imaging spectrometer in the form of a double hemispherical analyzer. In this paper, restricted to laboratory aspects of XPS spectromicroscopy, we will first give some details of this novel instrumentation after a short historical review of the field until the presently existing imaging techniques. Then, some of the first results of laboratory core-level XPEEM on practical samples will be presented. Future perspectives towards quantitative analysis, improvements of lateral resolution and multitechnique spectromicroscopic aspects with laboratory sources (including UPS spectromicroscopy in direct and reciprocal space) will be drawn.

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“…Spectromicroscopy, carried out by acquiring a series of parallel images at fixed energy intervals over an energy region of interest (e.g. a complex core level at high energy resolution, or a survey scan at low energy resolution) would normally be very time-consuming, but Walton and Fairley have recently demonstrated approaches to noise reduction using principal component analysis (PCA) 3 and, particularly, single value decomposition (SVD) sorting prior to PCA, 4 which can significantly reduce data acquisition times. These approaches, and other useful features for data interpretation which exploit them, have been incorporated into evolving thirdpart software.…”

Section: Introductionmentioning

confidence: 99%

Further developments in quantitative X-ray photoelectron spectromicroscopy: preliminary results from the study of germanium corrosion

Smith

Briggs

Fairley

2006

Surf. Interface Anal.

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The moisture-induced corrosion of an evaporated germanium film has been observed and studied using quantitative X-ray photoelectron spectromicroscopy. The application of recently reported software for the processing of multi-spectral image datasets (particularly noise reduction) to this real-world problem revealed the formation of oxide islands above the continuous passive oxide layer. The software has been developed to map the thickness of these structures within the XPS sampling depth, with a spatial resolution of a few microns. This exemplifies a characterisation methodology of use in any situation where (non-uniform) surface modification results in chemically shifted components of the same core level (or Auger peak) between the original substrate and new overlayer.

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Quantitative surface chemical‐state microscopy by x‐ray photoelectron spectroscopy

Cited by 36 publications

References 8 publications

Structure and growth of oxides on polycrystalline nickel surfaces

Structure and growth of oxides on polycrystalline nickel surfaces

High‐resolution XPS spectromicroscopy

Further developments in quantitative X-ray photoelectron spectromicroscopy: preliminary results from the study of germanium corrosion

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