Photoelektronenspektroskopie an Niobiodiden

Geyer-Lippmann, J.; Simon, Arndt; Stollmaier, Friederike

doi:10.1002/zaac.19845160909

Cited by 23 publications

(13 citation statements)

References 34 publications

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“…The second contribution to the Nb 3d peak [BE(Nb 3d 5/2 ) ¼ 205.5 eV, FWHM ¼ 1.8 eV, 25% of the overall Nb] was attributed to the presence of NbON, [31][32][33] while the high BE doublet [BE(Nb 3d 5/2 ) ¼ 207.5 eV, FWHM ¼ 2.4 eV] was ascribed to Nb 2 O 5 . [34][35][36][37][38][39][40][41][42][43] In accordance with the above observations, the presence of both niobium oxynitride and pentoxide species was attributed to the sample oxidation upon contact with the outer atmosphere. Regarding the O 1s signal, the component at BE ¼ 530.5 eV (FWHM ¼ 1.9 eV, 67.0% of the overall oxygen) could be related to Nb 2 O 5 , [38,41,42] but likely also accounted for oxygen from NbON.…”

Section: Chemical Composition: Rbs Xps and Snms Analysessupporting

confidence: 80%

Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

Thiede

Parala

Reuter

et al. 2009

Chemical Vapor Deposition

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Niobium nitride thin films are deposited on 2 00 silicon (100) wafers using a modified industrial metal-organic (MO) CVD reactor of the type AIX-200RF, starting from tert-butylamido-tris-(diethylamido)-niobium (TBTDEN) and ammonia. Films of thicknesses 50-200 nm are deposited at temperatures ranging from 400 8C to 800 8C under reactor pressures of 1 and 5 mbar using various ammonia flow rates, and are characterized by the use of complementary techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), secondary neutral mass spectrometry (SNMS), Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), and electrical measurements. Films deposited above 450 8C consist of the cubic d-NbN phase, apart from the presence of Nb-O and Nb-O-N species predominantly in the outermost film regions. The lowest specific resistivities, determined by four point probe measurements, are in the range 500-600 mV cm. A NbN/SiO 2 /p-Si gate stack is fabricated using the grown niobium nitride films. From the capacitance-voltage (C-V)-curves, flatband voltages are extracted which, when plotted against SiO 2 -insulator thickness, yield a work function of 4.72 eV for asdeposited films.

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Section: Chemical Composition: Rbs Xps and Snms Analysessupporting

confidence: 80%

Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

Thiede

Parala

Reuter

et al. 2009

Chemical Vapor Deposition

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“…Although there is a small shift to lower electron binding energies of Mo 3d 5/2 electrons in the Q-M1 sample compared to B-M1, binding energies values of close to 233 eV in M1 [27,28] and molybdenum oxides [29,30] are attributed to Mo 6+ . Binding energies of Te 3d 5/2 (576.7 eV) and Nb 3d 5/2 (207.3 eV) core levels in Q-M1 are attributed to Te 4+ [31,32] and Nb 5+ [33,34] oxidation states. V 2p 3/2 spectra typically shows two contributions with binding energies at 516.6 eV and 517.6 eV, attributed to V 4+ and V 5+ , respectively [28,31,35,36].…”

Section: Physicochemical Properties Of Quaternarymentioning

confidence: 96%

On the Promoting Effects of Te and Nb in the Activity and Selectivity of M1 MoV-Oxides for Ethane Oxidative Dehydrogenation

et al. 2020

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The pathways of ethane oxidative dehydrogenation and total combustion have been elucidated for M1 phase type Mo-V oxide catalysts with different metal composition. The ethane oxidation mechanism is not affected by the presence of Te or Nb. Conversely, the selectivity is strongly affected by stoichiometry of M1 catalysts. This is attributed to the facile oxidation of ethene to CO x upon formation of unselective VO x species in the absence of Te and Nb.

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“…Due to the additional electron coming from hydrogen atom insertion, the [HNb6I i 8] 3+ cluster core in HNb6I11 presents a VEC of 20 explaining the diamagnetic behavior observed at low temperature [40]. Photoelectron spectroscopy data indicated that insertion of hydrogen into Nb6I11 induces an increase of the oxidation state of niobium from ≈ 1.8 to ≈ 2.0 [56]. This result could be related with the weak polarization of hydrogen atom by neighboring niobium atoms highlighted by theoretical calculations performed with the self-consistent-field-X-scattered-wave (SCF-X-SW) method [57].…”

Section: Nb6i11-type (Ht and Lt Forms)mentioning

confidence: 99%

Inorganic Niobium and Tantalum Octahedral Cluster Halide Compounds with Three-Dimensional Frameworks: A Review on Their Crystallographic and Electronic Structures

Lemoine

Halet

Cordier

2019

Structure and Bonding

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This review summarizes the development of the rich crystal and bonding chemistry of facecapped and edge-bridged inorganic niobium and tantalum octahedral cluster halide compounds, with a particular emphasis on those showing three-dimensional cluster frameworks. Discussion is made on varied structures and bonding which are intimately linked to the valence electron concentration, i.e., the number of electrons that held the octahedral metal cluster architecture. Exploration of the literature indicates that apart from Nb6I11 and derivatives, which show electron-deficient face-capped M6X i 8X a 6 units, compounds containing edge-bridged M6X i 12X a 6 motifs are the most largely encountered. Closed-shell compounds with a valence electron concentration of 16 are predominant, although a few 15-electron open-shell magnetic compounds or even 14-electron closed-shell species have also been reported. Particularly interesting from a structural point of view is the fashion in which these facecapped and edge-bridged clusters "pack" in crystals. The astonishing diversity of structural types, which are observed, is mainly due to the flexibility of the halogen ligands to coordinate in various manners to metal atoms. However, a rigorous structural analysis of these compounds reveals no close relationship between the valence electron concentration and the variability of the intercluster connections and/or the nature of the counter-ions. Indeed, the main bonding features of these compounds can be understood from the delocalized bonding picture of isolated 'molecular-like' M6X i 8X a 6 or M6X i 12X a 6 clusters. Keywords Crystal structure  Electronic effect  Electronic structure  Halide  Inorganic compound  Interatomic distance  Intercluster distance  Ligand  Matrix effect  Metal-metal bond  Niobium  Octahedral cluster  Structure type  Tantalum  Three-dimensional framework  Valence electron concentration Contents 5 Cluster Frameworks of Structural Formula [M6X i 12X a-a 6/2] 5.1 Cluster Compounds with Linear M-X a-aM Bridges 5.2 Cluster Compounds with Bent M-X a-aM Bridges in Cubic Structure 5.3 Cluster Compounds with Bent M-X a-aM Bridges in Trigonal Structure 5.4 Cluster Compounds with Both Linear and Bent M-X a-aM Bridges 6 Interatomic Distances in Inorganic Nb6 and Ta6 Cluster Halide Compounds with Threedimensional Frameworks 6.1 Cluster Units Based on Face-capped M6X i 8X a 6 Building Blocks 6.2 Cluster Units Based on Edge-bridged M6X i 12X a 6 Building Blocks 7 Structural Relationships Between Crystal Structures Based on Hexagonal, Cubic and Trigonal Symmetry 8 Electronic Structure of Niobium and Tantalum Octahedral Cluster Halide Compounds 8.1 Variable VEC of Nb6I11 and Derivatives 8.2 Electronic Structure of Edge-bridged M6X i 12X a 6 Clusters 9 Summary References

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Photoelektronenspektroskopie an Niobiodiden

Cited by 23 publications

References 34 publications

Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

Deposition of Niobium Nitride Thin Films from Tert‐Butylamido‐Tris‐(Diethylamido)‐Niobium by a Modified Industrial MOCVD Reactor

On the Promoting Effects of Te and Nb in the Activity and Selectivity of M1 MoV-Oxides for Ethane Oxidative Dehydrogenation

Inorganic Niobium and Tantalum Octahedral Cluster Halide Compounds with Three-Dimensional Frameworks: A Review on Their Crystallographic and Electronic Structures

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