A UHV-compatible photoelectron emission microscope for applications in surface science

Engel, W.; Kordesch, Martin E.; Rotermund, Harm Hinrich; Kubala, S.; Oertzen, Alexander von

doi:10.1016/0304-3991(91)90146-w

Cited by 232 publications

(81 citation statements)

References 16 publications

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“…In addition, NEXAFS spectra can be obtained at high spatial resolution using imaging techniques such as photoemission electron microscopy [2][3][4][5] and magnetically-guided imaging 6 . The wealth of detailed information NEXAFS spectroscopy yields has made it an increasingly attractive analytical tool for several research fields, such as catalysis [7][8][9][10][11] , tribology 6,12,13 , self-assembly at surfaces [14][15][16][17] , nanomaterials [18][19][20][21][22][23][24][25][26] , and polymer science [27][28][29][30][31][32] .…”

Section: Introductionmentioning

confidence: 99%

Accounting for Nanometer-Thick Adventitious Carbon Contamination in X-ray Absorption Spectra of Carbon-Based Materials

et al. 2014

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Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometerscale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photo-absorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp 2 -hybridized carbon from 5 to 20%, and reveals that the adventitious contamination can be

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Section: Introductionmentioning

confidence: 99%

Accounting for Nanometer-Thick Adventitious Carbon Contamination in X-ray Absorption Spectra of Carbon-Based Materials

et al. 2014

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“…Molecules adsorbed at or near a surface dramatically influence the surface properties in applications such as corrosion inhibition, catalysis, electronics, wettability, and biocompatibility [1,2]. For investigation of the surface and interfacial structure, second-harmonic generation (SHG) and sum-frequency generation (SFG) are powerful techniques in material analysis.…”

Section: Introductionmentioning

confidence: 99%

Feasibility Study for Near-Field Optical Sum-Frequency Generation Spectroscopy Using a Metal-Coated Fiber

Miyamae

Tokizaki

2013

e-J. Surf. Sci. Nanotechnol.

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A near-field optical spectroscopy technique has been developed that collects the nonlinear sum-frequency signal from the surface adsorbed monolayer sample. The sum-frequency signal generated at the surface was collected with a silver-coated multi-mode fiber probe. The metal coating of the fiber effectively eliminates the far-field stray light that enters the core fiber from the outer edge, passing through the clad region. As the tip was pulled away from the sample surface, the sum-frequency signal from the GaAs crystal sample decreased rapidly with increasing tip-sample distance, indicating that the signal is essentially due to the near-field generated by the sum-frequency process. By using the metal-coated multi-mode fiber probe, information about the vibrational structure of the adsorbed molecules at the surfaces is studied.

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“…Engel et al, 1991;Ehsasi, 1994;Shidahara et al, 1996). The standard method uses a laboratory UV source to excite photoelectrons from areas with work functions lower than the energy of the lamp.…”

Section: Introductionmentioning

confidence: 99%

Development of X-ray photoemission electron microscopy (X-PEEM) at the SRS

Smith¹,

Cressey²,

Schofield³

et al. 1998

J Synchrotron Radiat

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The use of synchrotron radiation sources for X-ray spectroscopy is a well known and developed ®eld. The majority of applications, however, have been limited to studies of materials containing only a single phase of the element of interest. Owing to limited availability of suitable instrumentation, the study of materials comprising intergrowths of different phases has presented dif®culties in analysis. The majority of natural materials, including mineralogical samples, fall into this category. However, by applying the technique of photoemission electron microscopy (PEEM) to view the X-ray stimulated photoemission generated at an absorption edge, micro-area-selectable spectroscopy becomes possible. An instrument for X-ray PEEM (X-PEEM) is being developed at the Daresbury SRS and this paper shows how it can be used to obtain characteristic L-edge XANES spectra from ®nely intergrown iron oxide minerals.

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A UHV-compatible photoelectron emission microscope for applications in surface science

Cited by 232 publications

References 16 publications

Accounting for Nanometer-Thick Adventitious Carbon Contamination in X-ray Absorption Spectra of Carbon-Based Materials

Accounting for Nanometer-Thick Adventitious Carbon Contamination in X-ray Absorption Spectra of Carbon-Based Materials

Feasibility Study for Near-Field Optical Sum-Frequency Generation Spectroscopy Using a Metal-Coated Fiber

Development of X-ray photoemission electron microscopy (X-PEEM) at the SRS

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