Articles de revues : « X-ray Photoemission Spectroscopy (XPS) »

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Ekanayaka, Thilini K., Hannah Kurz, Kayleigh A. McElveen, Guanhua Hao, Esha Mishra, Alpha T. N’Diaye, Rebecca Y. Lai, Birgit Weber et Peter A. Dowben. « Evidence for surface effects on the intermolecular interactions in Fe(ii) spin crossover coordination polymers ». Physical Chemistry Chemical Physics 24, n^o 2 (2022) : 883–94. http://dx.doi.org/10.1039/d1cp04243b.

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From X-ray absorption spectroscopy (XAS) and X-ray photoemission spectroscopy (XPS) it is evident that the spin state transition behavior of Fe(ii) spin crossover coordination polymer crystallites at the surface differs from the bulk.

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Zhang, Hong-Guang, Yong-Tao Li, Liang Xie, Xue-Guang Dong et Qi Li. « Annealing temperature dependence of local atomic and electronic structure of polycrystalline La0.5Sr0.5MnO3 ». International Journal of Modern Physics B 29, n^o 03 (26 janvier 2015) : 1550006. http://dx.doi.org/10.1142/s021797921550006x.

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The local atomic and electronic structure of La 0.5 Sr 0.5 MnO 3 was investigated at different annealing temperatures (TA) by X-ray absorption spectroscopy (XAS) and photoemission spectroscopy (XPS). The extended X-ray absorption fine structure indicates that the MnO 6 octahedral distortion is reduced by increasing TA. The chemical shift for the sample with TA = 1350° C measured by XPS of Mn 2p core level demonstrates the increasing of Mn 3+ ions content. From the deconvolution of valence band photoemission spectra, the number of eg electron is also proved to increase with increasing TA. It is also demonstrated that there is a strongest hybridization between O 2p and surrounding atomic orbital states in sample with TA = 1350° C , which is consistent with valence band photoemission.

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Favaro, Marco, Mattia Cattelan, Stephen W. T. Price, Andrea E. Russell, Laura Calvillo, Stefano Agnoli et Gaetano Granozzi. « In Situ Study of Graphene Oxide Quantum Dot-MoSx Nanohybrids as Hydrogen Evolution Catalysts ». Surfaces 3, n^o 2 (16 juin 2020) : 225–36. http://dx.doi.org/10.3390/surfaces3020017.

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Graphene quantum dots (GOQDs)-MoSx nanohybrids with different MoSx stoichiometries (x = 2 and 3) were prepared in order to investigate their chemical stability under hydrogen evolution reaction (HER) conditions. Combined photoemission/electrochemical (XPS/EC) measurements and operando X-ray absorption spectroscopy (XAS) were employed to determine the chemical changes induced on the MoSx-based materials as a function of the applied potential. This in situ characterization indicates that both MoS2 and MoS3 materials are stable under operating conditions, although sulfur terminal sites in the MoS3 nanoparticles are converted from S-dimer (S22−) to S-monomer (S2−), which constitute the first sites where the hydrogen atoms are adsorbed for their subsequent evolution. In order to complete the characterization of the GOQDs-MoSx nanohybrids, the composition and particle size were determined by X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy; whereas the HER activity was studied by conventional electrochemical techniques.

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Zhu, Menglong, Lu Lyu, Dongmei Niu, Hong Zhang, Shitan Wang et Yongli Gao. « Effect of a MoO3 buffer layer between C8-BTBT and Co(100) single-crystal film ». RSC Advances 6, n^o 113 (2016) : 112403–8. http://dx.doi.org/10.1039/c6ra23981a.

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The effect of a MoO₃ buffer layer inserted between 2,7-dioctyl[1]benzothieno[3,2-b]benzothiophene (C8-BTBT) and Co single-crystal film has been investigated using X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS).

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Petraki, Fotini, Heiko Peisert, Johannes Uihlein, Umut Aygül et Thomas Chassé. « CoPc and CoPcF16 on gold : Site-specific charge-transfer processes ». Beilstein Journal of Nanotechnology 5 (25 avril 2014) : 524–31. http://dx.doi.org/10.3762/bjnano.5.61.

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Interface properties of cobalt(II) phthalocyanine (CoPc) and cobalt(II) hexadecafluoro-phthalocyanine (CoPcF16) to gold are investigated by photo-excited electron spectroscopies (X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and X-ray excited Auger electron spectroscopy (XAES)). It is shown that a bidirectional charge transfer determines the interface energetics for CoPc and CoPcF16 on Au. Combined XPS and XAES measurements allow for the separation of chemical shifts based on different local charges at the considered atom caused by polarization effects. This facilitates a detailed discussion of energetic shifts of core level spectra. The data allow the discussion of site-specific charge-transfer processes.

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El Jamal, Ghada, Thomas Gouder, Rachel Eloirdi et Mats Jonsson. « Time-dependent surface modification of uranium oxides exposed to water plasma ». Dalton Transactions 50, n^o 14 (2021) : 4796–804. http://dx.doi.org/10.1039/d1dt00486g.

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The dynamics of water plasma induced redox changes in UO₂ films are monitered with X-Ray photoelectron Photoemission (XPS) and Ultra-Violet Photoemission (UPS) spectroscopy as a function of exposure time.

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Cha, Myung Joo, Yu Jung Park, Jung Hwa Seo et Bright Walker. « Depth-dependent electronic band structure at the Au/CH3NH3PbI3−xClx junction ». Physical Chemistry Chemical Physics 21, n^o 27 (2019) : 14541–45. http://dx.doi.org/10.1039/c9cp00834a.

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The electronic properties of the interface between Au and the lead halide perovskite (CH₃NH₃PbI_3−xCl_x) were investigated by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS).

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Irfan, Franky So et Yongli Gao. « Photoemission Spectroscopy Characterization of Attempts to Deposit MoO2Thin Film ». International Journal of Photoenergy 2011 (2011) : 1–6. http://dx.doi.org/10.1155/2011/314702.

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Attempts to deposit molybdenum dioxide (MoO2) thin films have been described. Electronic structure of films, deposited by thermal evaporation of MoO2powder, had been investigated with ultraviolet photoemission and X-ray photoemission spectroscopy (UPS and XPS). The thermally evaporated films were found to be similar to the thermally evaporated MoO3films at the early deposition stage. XPS analysis of MoO2powder reveals presence of +5 and +6 oxidation states in Mo 3d core level along with +4 state. The residue of MoO2powder indicates substantial reduction in higher oxidation states while keeping +4 oxidation state almost intact. Interface formation between chloroaluminum phthalocyanine (AlPc-Cl) and the thermally evaporated film was also investigated.

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Kim, Geonhwa, Youngseok Yu, Hojoon Lim, Beomgyun Jeong, Jouhahn Lee, Jaeyoon Baik, Bongjin Simon Mun et Ki-jeong Kim. « AP-XPS beamline, a platform for operando science at Pohang Accelerator Laboratory ». Journal of Synchrotron Radiation 27, n^o 2 (28 janvier 2020) : 507–14. http://dx.doi.org/10.1107/s160057751901676x.

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Beamline 8A (BL 8A) is an undulator-based soft X-ray beamline at Pohang Accelerator Laboratory. This beamline is aimed at high-resolution ambient-pressure X-ray photoelectron spectroscopy (AP-XPS), soft X-ray absorption spectroscopy (soft-XAS) and scanning photoemission microscopy (SPEM) experiments. BL 8A has two branches, 8A1 SPEM and 8A2 AP-XPS, that share a plane undulator, the first mirror (M1) and the monochromator. The photon beam is switched between the two branches by changing the refocusing mirrors after the monochromator. The acceptance angle of M1 is kept glancing at 1.2°, and Pt is coated onto the mirrors to achieve high reflectance, which ensures a wide photon energy range (100–2000 eV) with high resolution at a photon flux of ∼1013 photons s−1. In this article, the main properties and performance of the beamline are reported, together with selected experiments performed on the new beamline and experimental system.

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Devan, Rupesh S., Shun-Yu Gao, Yu-Rong Lin, Shun-Rong Cheng, Chia-Er Hsu, Chia-Hao Chen, Hung-Wei Shiu, Yung Liou et Yuan-Ron Ma. « Scanning Photoemission Spectromicroscopic Study of 4-nm Ultrathin SiO3.4 Protrusions Probe-Induced on the Native SiO2 Layer ». Microscopy and Microanalysis 17, n^o 6 (11 octobre 2011) : 944–49. http://dx.doi.org/10.1017/s1431927611011901.

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AbstractAtomic force microscopy probe-induced large-area ultrathin SiOx (x ≡ O/Si content ratio and x > 2) protrusions only a few nanometers high on a SiO2 layer were characterized by scanning photoemission microscopy (SPEM) and X-ray photoemission spectroscopy (XPS). SPEM images of the large-area ultrathin SiOx protrusions directly showed the surface chemical distribution and chemical state specifications. The peak intensity ratios of the XPS spectra of the large-area ultrathin SiOx protrusions provided the elemental quantification of the Si 2p core levels and Si oxidation states (such as the Si4+, Si3+, Si2+, and Si1+ species). The O/Si content ratio (x) was evidently determined by the height of the large-area ultrathin SiOx protrusions.

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Biasotto, G., A. Z. Simões, C. S. Riccardi, M. A. Zaghete, E. Longo et J. A. Varela. « Retention Characteristics of CBTi144 Thin Films Explained by Means of X-Ray Photoemission Spectroscopy ». Advances in Materials Science and Engineering 2010 (2010) : 1–7. http://dx.doi.org/10.1155/2010/710269.

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CaBi4Ti4O15(CBTi144) thin films were grown on Pt/Ti/SiO2/Si substrates using a soft chemical solution and spin-coating method. Structure and morphology of the films were characterized by the X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman analysis, X-ray photoemission spectroscopy (XPS), and transmission electron microscopy (TEM). The films present a single phase of layered-structured perovskite with polar axis orient. Thea/b-axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. XPS measurements were employed to understand the nature of defects on the retention behavior of CBTi144 films. We have observed that the main source of retention-free characteristic of the capacitors is the oxygen environment in the CBTi144 lattice.

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Yagoub, Mubarak Y. A., Hendrik C. Swart et Elizabeth Coetsee. « Bulk and surface chemical compositions and microstructure properties of CaF₂:Y³⁺ material ». Journal of Vacuum Science & ; Technology B 41, n^o 1 (janvier 2023) : 014001. http://dx.doi.org/10.1116/6.0002279.

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The structural and chemical compositions of Y3+ ion-doped CaF2 were investigated as a possible lanthanide hosting material. A series of CaF2 nanomaterials doped with various concentrations of Y3+ ions under the chelating agent ethylene diamine tetraacetic acid (EDTA) were synthesized using the hydrothermal method. The x-ray diffraction results demonstrated that a mixture of cubic CaF2 and [CaY]F2 phases gradually formed with an increasing Y3+ ion concentration. A single [CaY]F2 cubic phase was formed when EDTA was added as the chelating agent. Scanning electron microscopy results demonstrated that the particle size and the morphology of the material depended on the Y3+ concentration and that EDTA (0.5 g) produced a spherical morphology. The surface and bulk chemical compositions were determined using a combined system of soft x-ray photoemission spectroscopy (XPS) (Al-Kα 1486.7 eV) and hard x-ray photoemission spectroscopy (HAXPES) (Cr-Kα 5414.7 eV). The relative changes in the chemical composition of the surface and subsurface/bulk were investigated. The combined XPS-HAXPES analysis demonstrated that the surface impurities in the accessible peaks (Ca 2p, Y 3d, and F 1s) completely diminished in the subsurface region. However, XPS-HAXPES analysis confirmed that the composition of the [CaY]F2 nanomaterial on the surface differs from that in the subsurface region.

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Chaiyo, Pitchanunt, Ladarat Kanlayavisut, Rinnatha Vongwatthaporn, Bok Ki Min, Seong Jun Kim, Ki Seok An, Supon Sumran et Supakorn Pukird. « Synthesis and Investigation of MoO₃ Microfilms and Nanorods by Thermal Chemical Vapor Deposition ». Key Engineering Materials 690 (mai 2016) : 23–27. http://dx.doi.org/10.4028/www.scientific.net/kem.690.23.

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MoO3 microfilms and nanorods can be synthesized by using the powder of MoS2 as starting materials by thermal chemical vapor deposition. The prepared products on substrates were investigated by field emission scanning electron microscope (FESEM), X-ray photoemission spectroscopy (XPS) and Raman spectroscopy. FESEM images showed the uniformly microfilms and nanorods-like with diameter around 50-100 nm and length of about through 5 μm, respectively. XPS patterns and Raman shifts revealed the prepared products consisting of MoO3 structure phases.

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Mishra, Esha, Subrata Majumder, Shikha Varma et Peter A. Dowben. « X-ray photoemission studies of the interaction of metals and metal ions with DNA ». Zeitschrift für Physikalische Chemie 236, n^o 4 (16 novembre 2021) : 439–80. http://dx.doi.org/10.1515/zpch-2021-3037.

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Abstract X-ray Photoelectron Spectroscopy (XPS) has been used to study the interactions of heavy metal ions with DNA with some success. Surface sensitivity and selectivity of XPS are advantageous for identifying and characterizing the chemical and elemental structure of the DNA to metal interaction. This review summarizes the status of what amounts to a large part of the photoemission investigations of biomolecule interactions with metals and offers insight into the mechanism for heavy metal-bio interface interactions. Specifically, it is seen that metal interaction with DNA results in conformational changes in the DNA structure.

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Nagai, Takehiko, Shinho Kim, Hitoshi Tampo, Kang Min Kim, Hajime Shibata, Shin’ichi Takaki, Kenta Kawasaki et al. « Band Alignment of CdS/Cu2ZnSnSe4 Heterointerface and Solar Cell Performances ». MRS Advances 2, n^o 53 (2017) : 3157–62. http://dx.doi.org/10.1557/adv.2017.315.

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ABSTRACTWe determined that the conduction band offset (CBO) and the valence band offset (VBO) at the CdS/ Cu2ZnSnSe4 (CZTSe) heterointerface are +0.56 and +0.89eV, respectively, by using X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and inversed photoemission spectroscopy (IPES). A positive CBO value, so-called “spike” structure, means that the position of conduction band becomes higher than that of absorber layer. The evaluated CBO of +0.56 eV suggests that the conduction band alignment at CdS/CZTSe interface is enough to become an electron barrier. Despite such a large spike structure in the conduction band at the interface, a conversion efficiency of 8.7 % could be obtained for the CdS/CZTSe heterojunction solar cells.

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Fraxedas, Jordi, Antje Vollmer, Norbert Koch, Dominique de Caro, Kane Jacob, Christophe Faulmann et Lydie Valade. « Characterization of Charge States in Conducting Organic Nanoparticles by X-ray Photoemission Spectroscopy ». Materials 14, n^o 8 (19 avril 2021) : 2058. http://dx.doi.org/10.3390/ma14082058.

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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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Susi, Toma, Thomas Pichler et Paola Ayala. « X-ray photoelectron spectroscopy of graphitic carbon nanomaterials doped with heteroatoms ». Beilstein Journal of Nanotechnology 6 (15 janvier 2015) : 177–92. http://dx.doi.org/10.3762/bjnano.6.17.

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X-ray photoelectron spectroscopy (XPS) is one of the best tools for studying the chemical modification of surfaces, and in particular the distribution and bonding of heteroatom dopants in carbon nanomaterials such as graphene and carbon nanotubes. Although these materials have superb intrinsic properties, these often need to be modified in a controlled way for specific applications. Towards this aim, the most studied dopants are neighbors to carbon in the periodic table, nitrogen and boron, with phosphorus starting to emerge as an interesting new alternative. Hundreds of studies have used XPS for analyzing the concentration and bonding of dopants in various materials. Although the majority of works has concentrated on nitrogen, important work is still ongoing to identify its precise atomic bonding configurations. In general, care should be taken in the preparation of a suitable sample, consideration of the intrinsic photoemission response of the material in question, and the appropriate spectral analysis. If this is not the case, incorrect conclusions can easily be drawn, especially in the assignment of measured binding energies into specific atomic configurations. Starting from the characteristics of pristine materials, this review provides a practical guide for interpreting X-ray photoelectron spectra of doped graphitic carbon nanomaterials, and a reference for their binding energies that are vital for compositional analysis via XPS.

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Syari’ati, Ali, Sumit Kumar, Amara Zahid, Abdurrahman Ali El Yumin, Jianting Ye et Petra Rudolf. « Photoemission spectroscopy study of structural defects in molybdenum disulfide (MoS2) grown by chemical vapor deposition (CVD) ». Chemical Communications 55, n^o 70 (2019) : 10384–87. http://dx.doi.org/10.1039/c9cc01577a.

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Mishra, Esha, Cody M. Schultz, Rebecca Y. Lai et Peter A. Dowben. « Coordination Chemistry of Uranyl Ions with Surface-Immobilized Peptides : An XPS Study ». Molecules 27, n^o 24 (16 décembre 2022) : 8960. http://dx.doi.org/10.3390/molecules27248960.

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The coordination chemistry of uranyl ions with surface immobilized peptides was studied using X-ray photoemission spectroscopy (XPS). All the peptides in the study were modified using a six-carbon alkanethiol as a linker on a gold substrate with methylene blue as the redox label. The X-ray photoemission spectra reveal that each modified peptide interacts differently with the uranyl ion. For all the modified peptides, the XPS spectra were taken in both the absence and presence of the uranium, and their comparison reveals that the interaction depends on the chemical group present in the peptides. The XPS results show that, among all the modified peptides in the current study, the (arginine)9 (R9) modified peptide showed the largest response to uranium. In the order of response to uranium, the second largest response was shown by the modified (arginine)6 (R6) peptide followed by the modified (lysine)6 (K6) peptide. Other modified peptides, (alanine)6 (A6), (glutamic acid)6 (E6) and (serine)6 (S6), did not show any response to uranium.

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Choi, Minuk, Christoph Brabec et Tomokatsu Hayakawa. « X-ray Diffraction, Micro-Raman and X-ray Photoemission Spectroscopic Investigations for Hydrothermally Obtained Hybrid Compounds of Delafossite CuGaO2 and Wurtzite ZnO ». Ceramics 5, n^o 4 (22 septembre 2022) : 655–72. http://dx.doi.org/10.3390/ceramics5040048.

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P-type delafossite CuGaO2 is a wide-bandgap semiconductor for optoelectronic applications, and its lattice parameters are very similar to those of n-type semiconductor wurtzite ZnO. Accordingly, the investigation of crystalline heterostructures of CuGaO2 and ZnO has attracted significant attention. In this study, interfacial CuGaO2/ZnO hetero-compounds were examined through X-ray diffraction (XRD) analysis, confocal micro-Raman spectroscopy, and X-ray photo-electron spectroscopy (XPS). XRD and Raman analysis revealed that the hydrothermal deposition of ZnO on hexagonal platelet CuGaO2 base crystals was successful, and the subsequent reduction process could induce a unique, unprecedented reaction between CuGaO2 and ZnO, depending on the deposition parameters. XPS allowed the comparison of the binding energies (peak position and width) of the core level electrons of the constituents (Cu, Ga, Zn, and O) of the pristine CuGaO2 single crystallites and interfacial CuGaO2/ZnO hybrids. The presences of Cu2+ ions and strained GaO6 octahedra were the main characteristics of the CuGaO2/ZnO hybrid interface. The XPS and modified Auger parameter analysis gave an insight into a specific polarization of the interface, promising for further development of CuGaO2/ZnO hybrids.

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Bastl, Zdeněk, et Heidrun Gehlmann. « X-ray photoelectron spectroscopic (XPS) studies of iodine oxocompounds ». Collection of Czechoslovak Chemical Communications 53, n^o 3 (1988) : 425–32. http://dx.doi.org/10.1135/cccc19880425.

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The core electron binding energies of eighteen compounds containing iodine in different oxidation states ranging from (-I) to (VII) have been measured. The observed chemical shifts differ from the literature data. The anticipated existence of hexavalent iodine in certain compounds has not been demonstrated. The relative subshell photoemission intensities of iodine have been determined. Empirically derived atomic sensitivity factors and theoretical photoionization cross-sections have been used to calculate the surface stoichiometry. The concentration ratios obtained via the two methods are compared. In agreement with generally accepted view the results of this comparison imply that, for quantitative surface analysis, empirical values should be used rather than theoretical data.

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Aliyev, Elvin, Volkan Filiz, Muntazim M. Khan, Young Joo Lee, Clarissa Abetz et Volker Abetz. « Structural Characterization of Graphene Oxide : Surface Functional Groups and Fractionated Oxidative Debris ». Nanomaterials 9, n^o 8 (18 août 2019) : 1180. http://dx.doi.org/10.3390/nano9081180.

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The purpose of this work is the structural analysis of graphene oxide (GO) and by means of a new structural model to answer the questions arising from the Lerf–Klinowski and the Lee structural models. Surface functional groups of GO layers and the oxidative debris (OD) stacked on them were investigated after OD was extracted. Analysis was performed successfully using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), X-ray photoemission spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, solid-state nuclear magnetic resonance spectroscopy (SSNMR), standardized Boehm potentiometric titration analysis, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that graphene oxide layers, as well as oxidative debris contain different functional groups such as phenolic –OH, ketone, lactone, carboxyl, quinone and epoxy. Based on these results, a new structural model for GO layers is proposed, which covers all spectroscopic data and explains the presence of the other oxygen functionalities besides carboxyl, phenolic –OH and epoxy groups.

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Chamlek, Onanong, S. Pratontep, Teerakiat Kerdcharoen et Tanakorn Osotchan. « Spectroscopys Studies of Iron Phthalocyanine Thin Films ». Advanced Materials Research 55-57 (août 2008) : 301–4. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.301.

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Iron phthalocyanine (FePc) thin films prepared by thermally evaporated from as received and purified powders were studied. The molecular interaction between FePc thin films and acetone vapor was studies by X-ray photoemission spectroscopy (XPS) and optical absorption spectrometer. The core level XPS spectra and optical absorption spectra showed slightly different between the spectra before and after acetone exposure. For FePc film evaporated with purified powder, only the Fe 2p3/2 spectra at about 712 eV appeared and the height of peak dramatically decreased. Iron K-edge X-ray absorption near edge structure (XANES) spectra was used to investigate iron atom in as received and purified powders and also study the interaction between FePc molecule and methanol vapor. The X-ray diffraction pattern of as received, annealed and purified FePc powder were investigated to study the crystal reformation and Raman spectroscopy was used to investigate iron atom vibration in as received FePc film.

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Xue, Shu Wen, et Xiao Tao Zu. « Investigation of Aluminum Content on the Properties of Sol-Gel-Derived Zinc Oxide Thin Films ». Materials Science Forum 561-565 (octobre 2007) : 1173–76. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1173.

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This paper reports that ZnO:Al films were deposited onto glass substrates by sol-gel process. Al/Zn atomic ratio varied in a wide range from 0 ~ 20%. The structural and optical properties were investigated by X-ray diffraction (XRD) and optical transmittance, respectively. X-ray photoemission spectroscopy (XPS) was used to investigate the elemental compositions. XRD results showed that ZnO films remained c-axis-orientated when Al/Zn atomic ratio was below 20% and the grain size decreased with increasing Al content. The optical transmittance showed that the optical bandgap of ZnO films blueshifted with increasing Al/Zn atomic ratio from 0-20%. XPS measurements showed that the binding energy of O1s increased with increasing Al content.

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Karstens, Reimer, Mathias Glaser, Axel Belser, David Balle, Małgorzata Polek, Ruslan Ovsyannikov, Erika Giangrisostomi, Thomas Chassé et Heiko Peisert. « FePc and FePcF16 on Rutile TiO2(110) and (100) : Influence of the Substrate Preparation on the Interaction Strength ». Molecules 24, n^o 24 (13 décembre 2019) : 4579. http://dx.doi.org/10.3390/molecules24244579.

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Interface properties of iron phthalocyanine (FePc) and perfluorinated iron phthalocyanine (FePcF16) on rutile TiO2(100) and TiO2(110) surfaces were studied using X-ray photoemission spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and low-energy electron diffraction (LEED). It is demonstrated that the interaction strength at the interfaces is considerably affected by the detailed preparation procedure. Weak interactions were observed for all studied interfaces between FePc or FePcF16 and rutile, as long as the substrate was exposed to oxygen during the annealing steps of the preparation procedure. The absence of oxygen in the last annealing step only had almost no influence on interface properties. In contrast, repeated substrate cleaning cycles performed in the absence of oxygen resulted in a more reactive, defect-rich substrate surface. On such reactive surfaces, stronger interactions were observed, including the cleavage of some C–F bonds of FePcF16.

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Griffiths, Lee, et Les Bradley. « Calculation of Carbonaceous Overlayer Thickness in XPS to Yield Substrate Stoichiometries ». Applied Spectroscopy 46, n^o 9 (septembre 1992) : 1426–30. http://dx.doi.org/10.1366/0003702924123809.

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A method has been developed which calculates the thickness of the hydrocarbon overlayer from x-ray photoemission spectroscopy (XPS) spectra. The method is specific to each sample and utilizes the relative intensity of the C 1 s peak and all other peaks. Attenuations calculated with this overlayer thickness yield more accurate substrate stoichiometries. A rough-sample model is also developed which not only explains previous anomalies in the thickness of hydrocarbon overlayer calculated but is capable of yielding further accuracy in substrate stoichiometries.

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Donkov, N., A. Zykova, V. Safonov, S. Dudin, S. Yakovin, A. Goltsev et T. Dubrava. « Surface treatment of magnetron-sputtered tantalum pentoxide coatings and its effect on the phenotype and function of immune cells in vitro ». Journal of Physics : Conference Series 2240, n^o 1 (1 mars 2022) : 012013. http://dx.doi.org/10.1088/1742-6596/2240/1/012013.

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Abstract The effect was analyzed of surface treatment by argon ions and electron beam on the properties of tantalum pentoxide coatings deposited by reactive magnetron sputtering and the treatment’s correlation with immune cells response. The characteristics of the coatings were determined by means of energy dispersive X-ray (EDX) scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), and atomic force microscopy (AFM). The results demonstrate that the electron-irradiation post-treatment process stimulates the adhesive potential and phagocytic activity of antigen-presenting cells.

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Iqbal, Z., E. Leone, R. Chin, A. J. Signorelli, A. Bose et H. Eckhardt. « X-ray photoemission spectroscopy of the 90 K superconductor Ba2YCu3O7−δ ». Journal of Materials Research 2, n^o 6 (décembre 1987) : 768–74. http://dx.doi.org/10.1557/jmr.1987.0768.

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The x-ray photoemission spectroscopie (XPS) data from different pelletized samples of the 90 K superconductor Ba2YCu3O7−δ (where δ∼0.2) have been obtained. The valence band spectrum (recorded at 300 and 170 K), which is composed of contributions from both the Cu 3d and O 2p levels, is compared with the full potential linearized augmented plane wave (FLAPW) calculated electronic density-of-states (DOS) reported by Massidda et al. and Mattheiss and Hamann. The experimental data indicate a relatively low DOS at the Fermi level. Detailed measurements of the core level Cu 2p, O 1s, Ba 3d, 4d, and Y 3d spectra of the superconducting and related standard materials, are presented. Data for the superconducting material were recorded in the freshly prepared form as well as after scraping in situ. The Cu 2p core level, satellite, and Auger spectra for the various samples were carefully examined in order to assess the possibility of the presence of Cu3+ ions in Ba2YCu3O7-δ. It is observed that surface reaction in air to form carbonates and hydroxides occurs readily in the superconducting material.

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Carvalho, Alexandra, Mariana C. F. Costa, Valeria S. Marangoni, Pei Rou Ng, Thi Le Hang Nguyen et Antonio H. Castro Neto. « The Degree of Oxidation of Graphene Oxide ». Nanomaterials 11, n^o 3 (24 février 2021) : 560. http://dx.doi.org/10.3390/nano11030560.

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We show that the degree of oxidation of graphene oxide (GO) can be obtained by using a combination of state-of-the-art ab initio computational modeling and X-ray photoemission spectroscopy (XPS). We show that the shift of the XPS C1s peak relative to pristine graphene, ΔEC1s, can be described with high accuracy by ΔEC1s=A(cO−cl)2+E0, where c0 is the oxygen concentration, A=52.3 eV, cl=0.122, and E0=1.22 eV. Our results demonstrate a precise determination of the oxygen content of GO samples.

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Li, Tian, Jun Peng Liao et Ying Feng Wang. « Solvothermal synthesis and magnetic properties of β-Co2P nanorods ». Materials Science-Poland 33, n^o 2 (1 juin 2015) : 312–16. http://dx.doi.org/10.1515/msp-2015-0049.

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AbstractHexagonal high temperature phase β-Co2P nanorods with a diameter of around 50 nm were synthesized via a mild solvothermal route. The reaction was carried out at 180 °C using cobalt chloride hexahydrate (CoCl2 · 6H2O) as Co source and yellow phosphorous as P source. The composition, structure as well as morphology were characterized by X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS) and transmission electron microscopy (TEM). The magnetic susceptibility curve indicates that the β-Co2P nanorods show canted antiferromagnetic state, different from the paramagnetic state of orthorhombic low temperature phase β-Co2P.

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Saito, Yoshihiro, Shigeaki Uemura, Tomohiro Kagiyama et Ryo Toyoshima. « XPS and HAXPES analyses for pre-sputtered InP surface and InP/Pt interface ». Japanese Journal of Applied Physics 61, n^o 3 (1 mars 2022) : 031005. http://dx.doi.org/10.35848/1347-4065/ac55e6.

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Abstract The state of the pre-sputtered indium phosphide (InP) surface was analyzed by X-ray photoelectron spectroscopy, employing synchrotron-based relatively low-energy X-ray. It was found that the pre-sputtering treatment induced the phosphorus vaporization and made the surface composition In-rich, which was thought to promote oxidation of InP surface in atmosphere. The state of the interface between InP and Pt was also investigated nondestructively, by using hard X-ray photoemission spectroscopy. As a result, it was demonstrated that the interfacial layer was composed of the native oxide (In–O, P–O) and metallic state (In–Pt or In–In, P–P) and that the pre-sputtering treatment increased significantly the amount of the P–O, In–Pt or In–In, and P–P. From a simplified calculation, assuming a Pt/In–Pt/In–P layer stacking structure and neglecting the In–O and P–O components, the thickness of the interfacial layer was estimated to be approximately 3.0 nm.

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Zhang, Sun, Shen, Hu, Hu, Jiang et Song. « Recent Progress with In Situ Characterization of Interfacial Structures under a Solid–Gas Atmosphere by HP-STM and AP-XPS ». Materials 12, n^o 22 (7 novembre 2019) : 3674. http://dx.doi.org/10.3390/ma12223674.

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: Surface science is an interdisciplinary field involving various subjects such as physics, chemistry, materials, biology and so on, and it plays an increasingly momentous role in both fundamental research and industrial applications. Despite the encouraging progress in characterizing surface/interface nanostructures with atomic and orbital precision under ultra-high-vacuum (UHV) conditions, investigating in situ reactions/processes occurring at the surface/interface under operando conditions becomes a crucial challenge in the field of surface catalysis and surface electrochemistry. Promoted by such pressing demands, high-pressure scanning tunneling microscopy (HP-STM) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS), for example, have been designed to conduct measurements under operando conditions on the basis of conventional scanning tunneling microscopy (STM) and photoemission spectroscopy, which are proving to become powerful techniques to study various heterogeneous catalytic reactions on the surface. This report reviews the development of HP-STM and AP-XPS facilities and the application of HP-STM and AP-XPS on fine investigations of heterogeneous catalytic reactions via evolutions of both surface morphology and electronic structures, including dehydrogenation, CO oxidation on metal-based substrates, and so on. In the end, a perspective is also given regarding the combination of in situ X-ray photoelectron spectroscopy (XPS) and STM towards the identification of the structure–performance relationship.

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Allimi, B. S., S. P. Alpay, D. Goberman, T. Huang, J. I. Budnick, D. M. Pease et A. I. Frenkel. « Growth of V2O3 thin films on a-plane (110) and c-plane (001) sapphire via pulsed-laser deposition ». Journal of Materials Research 22, n^o 10 (octobre 2007) : 2825–31. http://dx.doi.org/10.1557/jmr.2007.0378.

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We report the direct deposition of epitaxial 215-nm-thick vanadium sesquioxide (V2O3) films on a- and c-plane sapphire substrates from powder-pressed V2O3 targets via pulsed-laser deposition (PLD) in an evacuated deposition chamber devoid of O2. The films were characterized using x-ray diffraction (XRD), x-ray photoemission spectroscopy (XPS), x-ray absorption fine structure (XAFS) spectroscopy, and atomic force microscopy (AFM). XPS measurements confirmed that the stoichiometry of the powder was conserved in the films. XRD patterns together with XAFS measurements proved that V2O3 was epitaxial on the a-sapphire substrate with epitaxial relation (110)film//(110)substrate, and the results are consistent with the epitaxy on the c-plane substrate as well. The room-temperature resistivities of V2O3 films on a- and c-plane substrates were 1.49 × 10−4 and 3.00 × 10−5 Ω m, respectively. The higher resistivities of the films compared to bulk V2O3 might be attributed to thermal stresses resulting from difference in thermal expansion coefficients (TECs) of the films and the substrates.

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Khan, Shadab Ali, Sanjay Gambhir et Absar Ahmad. « Extracellular biosynthesis of gadolinium oxide (Gd2O3) nanoparticles, their biodistribution and bioconjugation with the chemically modified anticancer drug taxol ». Beilstein Journal of Nanotechnology 5 (7 mars 2014) : 249–57. http://dx.doi.org/10.3762/bjnano.5.27.

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As a part of our programme to develop nanobioconjugates for the treatment of cancer, we first synthesized extracellular, protein-capped, highly stable and well-dispersed gadolinium oxide (Gd2O3) nanoparticles by using thermophilic fungus Humicola sp. The biodistribution of the nanoparticles in rats was checked by radiolabelling with Tc-99m. Finally, these nanoparticles were bioconjugated with the chemically modified anticancer drug taxol with the aim of characterizing the role of this bioconjugate in the treatment of cancer. The biosynthesized Gd2O3 nanoparticles were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). The Gd2O3–taxol bioconjugate was confirmed by UV–vis spectroscopy and fluorescence microscopy and was purified by using high performance liquid chromatography (HPLC).

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BAI, XUXU, WANQI JIE, GANGQIANG ZHA, WENHUA ZHANG, JUNFA ZHU, DONG QIAN et JINFENG JIA. « THE ADSORPTION AND DESORPTION OF OXYGEN ON CdZnTe (111)B-(2 × 2) SURFACE ». Surface Review and Letters 20, n^o 03n04 (août 2013) : 1320001. http://dx.doi.org/10.1142/s0218625x13200011.

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The oxygen adsorption and desorption on the CdZnTe (111) B -(2×2) surface were studied with synchrotron radiation ultraviolet photoemission spectroscopy (SRUPS) and X-ray photoelectron spectroscopy (XPS). The results show that a surface state of clean CdZnTe (111) B -(2×2) surface appears at 0.5 eV below Fermi level ( E F), which disappears after the oxygen exposure, and shows again after annealing in UHV. The surface work function of CdZnTe (111) B -(2×2) decreases after the oxygen exposure, and futher reduces after annealing.

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Ishihara, Tomoko, Takuo Ohkochi, Akinobu Yamaguchi, Yoshinori Kotani et Masaki Oura. « Visualization of elemental distributions and local analysis of element-specific chemical states of an Arachnoidiscus sp. frustule using soft X-ray spectromicroscopy ». PLOS ONE 15, n^o 12 (16 décembre 2020) : e0243874. http://dx.doi.org/10.1371/journal.pone.0243874.

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Using soft X-ray (SX) spectromicroscopy, we show maps of the spatial distribution of constituent elements and local analysis of the density of states (DOS) related to the element-specific chemical states of diatom frustules, which are composed of naturally grown nanostructured hydrogenated amorphous silica. We applied X-ray photoemission electron microscopy (X-PEEM) as well as microprobe X-ray fluorescence (μXRF) analysis to characterize the surfaces of diatom frustules by means of X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). We successfully demonstrated that SX spectromicroscopy is able to participate in potential observation tools as a new method to spectroscopically investigate diatom frustules.

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Liu, Baoxing, Haipeng Xie, Yuan Zhao, Dongmei Niu et Yongli Gao. « MoO3 Interlayer Modification on the Electronic Structure of Co/BP Interface ». Symmetry 14, n^o 11 (18 novembre 2022) : 2448. http://dx.doi.org/10.3390/sym14112448.

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The modification by molybdenum trioxide (MoO3) buffer layer on the electronic structure between Co and black phosphorus (BP) was investigated with ultraviolet photoemission spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS). It was found that the MoO3 buffer layer could effectively prevent the destruction of the outermost BP lattice during the Co deposition, with the symmetry of the lattice remaining maintained. There is a noticeable interfacial charge transfer in addition to the chemical reaction between Co and MoO3. The growth pattern of Co deposited onto the MoO3/BP film is the island growth mode. The observations reveal the significance of a MoO3 buffer layer on the electronic structure between Co and black phosphorus and provide help for the design of high-performance Co/BP-based spintronic devices.

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Pedraza, A. J., J. W. Park, H. M. Meyer et D. N. Braski. « X-ray photoelectron spectroscopy of uv laser irradiated sapphire and alumina ». Journal of Materials Research 9, n^o 9 (septembre 1994) : 2251–57. http://dx.doi.org/10.1557/jmr.1994.2251.

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X-ray photoelectron spectroscopy (XPS) was performed in as-received, thermally annealed, and laser-irradiated sapphire and alumina specimens in order to study the effects of the different treatments on surface chemistry and properties. Laser irradiations with a 308 nm wavelength laser were performed in air and in a reducing atmosphere consisting of a mixture of Ar and 4% of hydrogen. The atomic percentages of carbon, aluminum, and oxygen were measured in all the specimens. Particular attention was paid to the percentages of oxygen in the oxide and in a hydroxyl state. The XPS analyses clearly established that a very thin film of metallic aluminum is formed on the surface of both alumina and sapphire substrates when they are irradiated under a reducing atmosphere. However, the film is discontinuous because it is electrically insulating. Substrates irradiated in air have metallic aluminum only for fluences below 0.4 J/cm2. The valence band photoemission spectra of as-received, annealed, and laser-irradiated specimens were measured. In irradiated specimens, the width of the valence band spectra was found to decrease by ∼10%. One possible cause of this decrease is the generation of point defects during laser irradiation. Electroless copper deposition occurs on sapphire and alumina substrates if their surface has been activated by laser irradiation. The time required for copper deposition was monitored by measuring the electrical resistivity in the irradiated area while the substrates were immersed in an electroless bath. The kinetics of deposition on laser-activated substrates and the XPS results show that the presence of metallic aluminum accelerates the deposition process. However, the presence of aluminum is not the sole reason for laser activation in alumina. Very strong metal-ceramic bonding is produced after thermal annealing of samples having preirradiated substrates. This result is explained in terms of the excess oxygen that is present at the ceramic surface after irradiation.

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ATUCHIN, V. V., L. D. POKROVSKY, V. G. KESLER, N. YU. MAKLAKOVA, V. I. VORONKOVA et V. K. YANOVSKII. « SUPERSTRUCTURE FORMATION AND X-RAY PHOTOEMISSION PROPERTIES OF THE TlTiOPO4 SURFACE ». Surface Review and Letters 11, n^o 02 (avril 2004) : 191–98. http://dx.doi.org/10.1142/s0218625x04006013.

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X-ray photoemission spectroscopy (XPS) measurements have been executed for TlTiOPO 4 to elucidate the general features in the electronic structure of the KTiOPO 4 family compounds. The peculiarities of the valence band structure have been discussed for the crystals. The persistence of core level binding energy differences O 1s–P 2p and O 1s–Ti 2p 3/2 has been detected in TlTiOPO 4 and KTiOPO 4, which relates well with the constancy of averaged P – O and Ti – O chemical bond lengths in this crystal family. The superstructure ordering of the TlTiOPO 4 surface subjected to polishing and annealing has been detected by reflectance high energy electron diffraction (RHEED). From comparison of surface crystallographic properties of TlTiOPO 4 and KTiOPO 4, the most typical superstructure indices have been revealed.

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Klebanoff, L. E. « Technical and personal remembrances of David A. Shirley in studies of surface magnetism, photoelectron spectroscopy, EUV lithography, and hydrogen storage ». Journal of Vacuum Science & ; Technology A 40, n^o 3 (mai 2022) : 033206. http://dx.doi.org/10.1116/6.0001816.

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This article describes the influence of Professor David A. Shirley on the research science of one of his Ph.D. students in the diverse areas of surface magnetism, x-ray photoelectron spectroscopy (XPS), spin-resolved XPS (SRXPS), extreme ultraviolet (EUV) lithography, and hydrogen storage materials science. Examples are given from the author's work on Cr(001) surface magnetism, XPS, and SRXPS studies of multiplet-splitting in core-level photoemission from Fe. In addition, Dave's influence in understanding the radiation-induced deposition of carbon on EUV optics is described, along with the use of XPS in deciphering how hydrogen storage materials are modified by repeated hydrogen adsorption/desorption cycling. The current status of these particular topics is briefly summarized. These technical remembrances are combined with some fond personal stories about Dave, in recognition of his passing on March 29, 2021.

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Klebanoff, L. E. « Technical and personal remembrances of David A. Shirley in studies of surface magnetism, photoelectron spectroscopy, EUV lithography, and hydrogen storage ». Journal of Vacuum Science & ; Technology A 40, n^o 3 (mai 2022) : 033206. http://dx.doi.org/10.1116/6.0001816.

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This article describes the influence of Professor David A. Shirley on the research science of one of his Ph.D. students in the diverse areas of surface magnetism, x-ray photoelectron spectroscopy (XPS), spin-resolved XPS (SRXPS), extreme ultraviolet (EUV) lithography, and hydrogen storage materials science. Examples are given from the author's work on Cr(001) surface magnetism, XPS, and SRXPS studies of multiplet-splitting in core-level photoemission from Fe. In addition, Dave's influence in understanding the radiation-induced deposition of carbon on EUV optics is described, along with the use of XPS in deciphering how hydrogen storage materials are modified by repeated hydrogen adsorption/desorption cycling. The current status of these particular topics is briefly summarized. These technical remembrances are combined with some fond personal stories about Dave, in recognition of his passing on March 29, 2021.

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Fang, L. L., Bing Lin Zhang et Ning Yao. « Fabrication of Accurate Diamond - Metal Composite Cutting Blade by Electrotyping Method ». Key Engineering Materials 304-305 (février 2006) : 57–61. http://dx.doi.org/10.4028/www.scientific.net/kem.304-305.57.

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In this paper, we report that the experimental results of fabricated diamond-metal composite film. Electrotyping method was used to deposit the thick film. During the deposition, low internal stress electrolytic solution, the electric current density of cathode, PH value, temperature, the distance between cathode and anode, the pretreatment of motherboard cathode were selected simultaneously. It was found that stirring strongly affected the quality of the film. Especially stirring velocity affected the distribution of diamond grains. Scanning electron microscope (SEM), X-ray photoemission spectroscopy (XPS) and X-ray diffraction (XRD) were used to measure the surface morphology, the crystal microstructure, diamond grains distribution and the chemical environment of the film.

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Alonzo, Giuseppe, Nuccio Bertazzi, John R. Ferraro, Anita Furlani, Giovanna Iucci, Giovanni Polzonetti et Maria V. Russo. « Mössbauer, Far-Infrared, and XPS Investigations of SnCl2 and SnCl4 Introduced in Polyconjugated Monosubstituted Acetylene Matrices ». Applied Spectroscopy 49, n^o 2 (février 1995) : 237–40. http://dx.doi.org/10.1366/0003702953963742.

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Mössbauer, far-infrared, and X-ray photoemission spectroscopy (XPS) studies have been made on doped (SnCl2 or SnCl4) (PEFl) and polyphenylacetylene (PPA). The nature of the tin as it is incorporated into the polymer is examined. The resistance values of the doped polymers are followed with relative humidity. Results point to tetrahedral (SnCl4 and octahedral (SnCl4 · 2H2O) species in the SnCl4 doping. With SnCl2 doping, the nature of the species is less certain, although both Sn(II) and hexacoordinated Sn(IV) appear to be present. Index Headings: Mössbauer

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Pukird, Supakorn, Dheerachai Polsongkram, Suttinart Noothongkeaw, Khanidtha Jantasom et Ki Seok An. « Synthesis and Characterization of CuO/SnO2 Nanocomposites ». Applied Mechanics and Materials 575 (juin 2014) : 175–79. http://dx.doi.org/10.4028/www.scientific.net/amm.575.175.

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CuO/SnO2 nanocomposites materials were prepared by solution coprecipitation process using CuO nanowires-rods and SnO2 nanowires mixture as a starting materials. The mixture materials were put in beaker glass with distilled water and magnetic stering at 90 oC for 3 h. The mixture materials were filtered and heated at 980 oC for 20 h. The prepared products were investigated by FE scanning electron microscope (FESEM), X-rays photoemission spectroscopy (XPS) and X-ray driffraction technique (XRD). The results showed nanocomposites structures which consisting of CuO and SnO2 phase.

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Kim, Young K., Delroy A. Baugh, David K. Shuh, R. Stanley Williams, Larry P. Sadwick et Kang L. Wang. « Structural and chemical stability of thin films of Pt–Ga intermetallic compounds of GaAs(001) ». Journal of Materials Research 5, n^o 10 (octobre 1990) : 2139–51. http://dx.doi.org/10.1557/jmr.1990.2139.

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Nearly single-phase thin films of three different Pt–Ga intermetallic compounds have been grown on GaAs(001) by co-deposition of Pt and Ga. The resultant films have been annealed at various temperatures and then characterized using x-ray two-theta diffractometry (XRD), Auger electron spectroscopy (AES), and x-ray photoemission spectroscopy (XPS). The XRD results showed that PtGa2 and PtGa thin films are chemically stable on GaAs under one atmosphere of N2 up to 800 °C and 600 °C, respectively, but thin films of Pt2Ga react with GaAs at temperatures as low as 200 °C to form phases with higher Ga concentration PtAs2. The XRD patterns also revealed that the crystallite orientation and texture of the films were dependent on annealing temperature. Segregation of Ga to the surfaces of the films upon annealing was also observed by both AES and XPS. The results demonstrated that the as-deposited films of PtGa2 and PtGa were kinetically stabilized with respect to possible chemical reactions with the GaAs substrates that evolve gaseous As species during open system annealing.

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Al-Atabi, Hayder A., Xiaotian Zhang, Shanmei He, Cheng chen, Yulin Chen, Eli Rotenberg et James H. Edgar. « Lattice and electronic structure of ScN observed by angle-resolved photoemission spectroscopy measurements ». Applied Physics Letters 121, n^o 18 (31 octobre 2022) : 182102. http://dx.doi.org/10.1063/5.0119628.

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Scandium nitride (ScN) has recently attracted much attention for its potential applications in thermoelectric energy conversion, as a semiconductor in epitaxial metal/semiconductor superlattices, as a substrate for GaN growth, and alloying it with AlN for 5G technology. This study was undertaken to better understand its stoichiometry and electronic structure. ScN (100) single crystals 2 mm thick were grown on a single crystal tungsten (100) substrate by a physical vapor transport method over a temperature range of 1900–2000 °C and a pressure of 20 Torr. The core level spectra of Sc 2 p3/2,1/2 and N 1 s were obtained by x-ray photoelectron spectroscopy (XPS). The XPS core levels were shifted by 1.1 eV toward higher values as the [Sc]:[N] ratio varied from 1.4 at 1900 °C to ∼1.0 at 2000 °C due to the higher binding energies in stoichiometric ScN. Angle-resolved photoemission spectroscopy measurements confirmed that ScN has an indirect bandgap of ∼1.2 eV.

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Zhou, Wei, Su Jing Xia, Xiang Li, Jie Yang et Wu Tang. « The Effect of the Native Oxidation on the Characteristic of Surface Electron in the In_0.13Al_0.87N Epilayer Grown by MOCVD ». Advanced Materials Research 335-336 (septembre 2011) : 655–58. http://dx.doi.org/10.4028/www.scientific.net/amr.335-336.655.

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The property of surface electron in undoped IIn0.13Al0.87N epilayers with different thicknesses has been investigated using x-ray photoemission spectroscopy (XPS) and micro-Raman scattering spectra. XPS has been used to determine the characteristic of the native oxide at the free surfaces of In0.13Al0.87N film. It is showed that the binding energy shift to higher with the thickness reduction from the Al 2p, N 1s, In 3d5/2 spectra. While, there is more native oxide at the surface of In0.13Al0.87N film with the decrease of thickness. In addition, a broad peak in high energy region was only observed in the thinnest In0.13Al0.87N epilayer from micro-Raman results, and it may be relative to L+ coupled mode of In0.13Al0.87N.

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Bhola, Rahul, Shaily M. Bhola, Brajendra Mishra, Reed Ayers, David L. Olson et Timothy Ohno. « Cellular Response of Titanium and Its Alloys as Implants ». Journal of Oral Implantology 37, n^o 4 (1 août 2011) : 387–99. http://dx.doi.org/10.1563/aaid-joi-d-09-00075.1.

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Abstract The cellular response of osteocytes to commercially pure titanium (α) and its alloys (α + β and β) has been tested in a culture media, and the results have been supplemented by analyses from various techniques such as inductively coupled plasma atomic emission spectroscopic (ICP-AES) analysis, X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), metallography, and electrochemical measurements. These results have been correlated with respect to the presence of various alloying elements in these alloys to qualify them for human application. The newer β alloys have been examined for their potential use as implants. These results serve as a preliminary baseline to characterize the best alloy system for a comprehensive long-term investigation.

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Gonzalez-Valls, Irene, Belén Ballesteros et Mónica Lira-Cantu. « Vertically Aligned ZnO/InxSy Core–Shell Nanorods for High Efficient Dye-Sensitized Solar Cells ». Nano 10, n^o 07 (octobre 2015) : 1550103. http://dx.doi.org/10.1142/s1793292015501039.

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Innovative vertically aligned ZnO / In x S y nanorod (NR) electrodes were prepared by successive ion layer adsorption and reaction (SILAR) technique. The In x S y shell layer was deposited on top of ZnO NR electrodes of two different lengths, ~1.6 μm and ~3.2 μm. Two sulfur contents on the In x S y shell layer with different layer thicknesses were analyzed. These electrodes were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), Energy-dispersive x-ray spectroscopy (EDS), Infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) and then applied in dye-sensitized solar cells (DSC). Power conversion efficiency of 2.32% was observed when a low-sulfur content In x S y shell layer was applied in comparison to the stoichiometric In 2 S 3 shell layer (0.21%) or the bare ZnO NRs (0.87%). In the case of low sulfur content, a shell layer of In ( OH )x S y or/and In ( OH )3 is formed as observed by the presence of – OH observed by FTIR analyses. The presence of higher amounts of hydroxide groups modifies the bandgap and work function of the In x S y shell and facilitates dye adsorption, increasing the final solar cell performance.

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Moretti, Arianna, Diogo Vieira Carvalho, Niloofar Ehteshami, Elie Paillard, Willy Porcher, David Brun-Buisson, Jean-Baptiste Ducros et al. « A Post-Mortem Study of Stacked 16 Ah Graphite//LiFePO4 Pouch Cells Cycled at 5 °C ». Batteries 5, n^o 2 (7 mai 2019) : 45. http://dx.doi.org/10.3390/batteries5020045.

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Herein, the post-mortem study on 16 Ah graphite//LiFePO4 pouch cells is reported. Aiming to understand their failure mechanism, taking place when cycling at low temperature, the analysis of the cell components taken from different portions of the stacks and from different positions in the electrodes, is performed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS). Also, the recovered electrodes are used to reassemble half-cells for further cycle tests. The combination of the several techniques detects an inhomogeneous ageing of the electrodes along the stack and from the center to the edge of the electrode, most probably due to differences in the pressure experienced by the electrodes. Interestingly, XPS reveals that more electrolyte decomposition took place at the edge of the electrodes and at the outer part of the cell stack independently of the ageing conditions. Finally, the use of high cycling currents buffers the low temperature detrimental effects, resulting in longer cycle life and less inhomogeneities.

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