Characterization of free-standing InAs quantum membranes by standing wave hard x-ray photoemission spectroscopy

Pd/Y multilayers are high-reflectance mirrors designed to work in the 7.5–11 nm wavelength range. Samples, prepared by magnetron sputtering, are deposited with or without B4C barrier layers located at the interfaces of the Pd and Y layers to reduce interdiffusion, which is expected from calculating the mixing enthalpy of Pd and Y. Grazing-incident X-ray reflectometry is used to characterize these multilayers. B4C barrier layers are found to be effective in reducing Pd–Y interdiffusion. Details of the composition of the multilayers are revealed by hard X-ray photoemission spectroscopy with X-ray standing wave effects. This consists of measuring the photoemission intensity from the samples by performing an angular scan in the region corresponding to the multilayer period and an incident photon energy according to Bragg's law. The experimental results indicate that Pd does not chemically react with B nor C at the Pd–B4C interface while Y does react at the Y–B4C interface. The formation of Y–B or Y–C chemical compounds could be the reason why the interfaces are stabilized. By comparing the experimentally obtained angular variation of the characteristic photoemission with theoretical calculations, the depth distribution of each component element can be interpreted.

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Synthesis and characterization of TiN / Ti / AISI 410 coatings

Journal of Sciences and Engineering ◽

10.32829/sej.v2i1.54 ◽

2018 ◽

Vol 2 (1) ◽

pp. 7

Author(s):

S Chirino ◽

Jaime Diaz ◽

N Monteblanco ◽

E Valderrama

Keyword(s):

Synthesis And Characterization ◽

Photoemission Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Columnar Grains ◽

Tin Thin Films ◽

Steel Aisi ◽

Interacting Surfaces ◽

Stainless Steel Aisi

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified. Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.

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Characterization of Charge States in Conducting Organic Nanoparticles by X-ray Photoemission Spectroscopy

Materials ◽

10.3390/ma14082058 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2058

Author(s):

Jordi Fraxedas ◽

Antje Vollmer ◽

Norbert Koch ◽

Dominique de Caro ◽

Kane Jacob ◽

...

Keyword(s):

Partial Oxidation ◽

Chemical Shifts ◽

Large Family ◽

Photoemission Spectroscopy ◽

Intrinsic Structure ◽

X Ray ◽

Level Lines ◽

Donor And Acceptor ◽

Electronic Configurations

The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors.

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Characterization of reconstructed SiC(100) surfaces using soft‐x‐ray photoemission spectroscopy

Applied Physics Letters ◽

10.1063/1.114061 ◽

1995 ◽

Vol 66 (4) ◽

pp. 475-477 ◽

Cited By ~ 75

Author(s):

V. M. Bermudez ◽

J. P. Long

Keyword(s):

Photoemission Spectroscopy ◽

X Ray

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Layer-resolved many-electron interactions in delafossite PdCoO2 from standing-wave photoemission spectroscopy

Communications Physics ◽

10.1038/s42005-021-00643-y ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Qiyang Lu ◽

Henrique Martins ◽

Juhan Matthias Kahk ◽

Gaurab Rimal ◽

Seongshik Oh ◽

...

Keyword(s):

Charge Transfer ◽

Standing Wave ◽

Three Dimensional ◽

Photoemission Spectroscopy ◽

Electronic Coupling ◽

Many Body ◽

X Ray ◽

Charge Transfer Excitons ◽

Many Body Interactions ◽

Electron Interactions

AbstractWhen a three-dimensional material is constructed by stacking different two-dimensional layers into an ordered structure, new and unique physical properties can emerge. An example is the delafossite PdCoO2, which consists of alternating layers of metallic Pd and Mott-insulating CoO2 sheets. To understand the nature of the electronic coupling between the layers that gives rise to the unique properties of PdCoO2, we revealed its layer-resolved electronic structure combining standing-wave X-ray photoemission spectroscopy and ab initio many-body calculations. Experimentally, we have decomposed the measured VB spectrum into contributions from Pd and CoO2 layers. Computationally, we find that many-body interactions in Pd and CoO2 layers are highly different. Holes in the CoO2 layer interact strongly with charge-transfer excitons in the same layer, whereas holes in the Pd layer couple to plasmons in the Pd layer. Interestingly, we find that holes in states hybridized across both layers couple to both types of excitations (charge-transfer excitons or plasmons), with the intensity of photoemission satellites being proportional to the projection of the state onto a given layer. This establishes satellites as a sensitive probe for inter-layer hybridization. These findings pave the way towards a better understanding of complex many-electron interactions in layered quantum materials.

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