XPS Studies at the Interface of Ti/AIN Ceramic

1994 ◽  
Vol 357 ◽  
Author(s):  
Dian Hong Shen ◽  
Changlin Bao ◽  
Hua Lu ◽  
Zhangda Lin
Keyword(s):  
Lower Energy ◽  
Room Temperature ◽  
Binding Energies ◽  
Ceramic Substrate ◽  
Photoelectron Spectra ◽  
Oxygen Binding ◽  
Metallic Titanium ◽  
Alumina Layer ◽  
Hydrated Alumina ◽  
Two Peaks

AbstractThe photoelectron spectra for titanium deposition on a AIN ceramic substrate at room temperature have been measured. Before deposition, the binding energies of Ols and Al 2p show that the substrate contained oxygen as a major impurity and a top layer of degeneration was formed. After deposition of a small amount of titanium, it was found that the Nls separated into two peaks(396.5 eV and 402 eV) and Ti 2p corresponded to the oxide state. With an increase of titanium coverage, the Ti 2p peak shifted toward a lower energy. The peak at 402 eV dominated at a titanium coverage of 0.9 nm, showing the nitrogen-oxygen binding character. For a titanium coverage of 3.0 nm, a new peak at 406 eV was formed. These results suggest that during deposition of Ti onto the AIN substrate which has a top hydrated alumina layer, some of nitrogen atoms tend to be bound with oxygen and to form an interfacial oxynitride layer between the metallic titanium and substrate.

scholarly journals Photoelectron Spectroscopy using Pulsed Free Jets

1986 ◽  
Vol 39 (5) ◽  
pp. 789 ◽  
Author(s):  
Frank Carnovale ◽  
J Barrie Peel ◽  
Richard G Rothwell
Keyword(s):  
Band Structure ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Free Jets ◽  
Free Jet ◽  
Hot Band ◽  
The One ◽  
Ammonia Clusters

The use of pulsed gaseous free jets in the study of atomic and molecular species by ultraviolet photoelectron spectroscopy (UPS) offers a number of advantages over the usual continuous flow room temperature technique. Pulsed free jet expansions provide, on the one hand, 'cold' molecules for which spectroscopy is simplified through the absence of hot band structure and, on the other hand, cluster species including dimers, trimers and higher clusters, as well as intermolecular species, all generally of low intermolecular binding energies. Furthermore a high pressure gas pulse is a suitable medium for the preparation, relaxation and transport of reactive species formed in processes such as pyrolysis, photodissociation or electrical discharge. This paper describes the modifications made to an ultraviolet photoelectron spectrometer to allow measurements on pulsed free jet expansions. The important features of the modified instrument concern the control of the gas beam and the timing electronics for photoelectron detection. Examples of He I photoelectron spectra presented include (a) the demonstration of hot band structure in the room temperature UPS of ammonia, (b) the preparation of the dimer (NOh and higher clusters (NO) n of nitric oxide, (c) the UPS of sulfur dioxide clusters (S02) n' and (d) the UPS of ammonia clusters (NH 3) n'

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

Theoretical core spectroscopy of molecules interacting with ice surfaces 

2021 ◽  
Author(s):  
Richard Asamoah Opoku
Keyword(s):  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Trace Gases ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Development Fund ◽  
Xps Spectra ◽  
The Core ◽  
Ice Surfaces

<p><strong>Céline TOUBIN</strong><strong><sup>2</sup></strong><strong> and </strong><strong>André Severo Pereira GOMES</strong><strong><sup> 3</sup></strong></p><p><sup>2,3</sup> Laboratoire de Physique des Lasers, des atomes et des Molécules, Université de Lille, Cité Scientifique, 59655 Villeneuve d’Ascq Cedex, France</p><p>E-mail : [email protected]<sup>2</sup> ; [email protected]<sup>3</sup></p><p>Ice plays an essential role as a catalyst for reactions between atmospheric trace gases. The uptake of trace gases to ice has been proposed to have a major impact on geochemical cycles, human health, and ozone depletion in the stratosphere [1]. X-ray photoelectron spectroscopy (XPS) [2], serves as a powerful technique to characterize the elemental composition of such interacting species due to its surface sensitivity. Given the existence of complex physico-chemical processes such as adsorption, desorption, and migration within ice matrix, it is important to establish a theoretical framework to determine the electronic properties of these species under different conditions such as temperature and concentration. The focus of this work is to construct an embedding methodology employing Density Functional (DFT) and Wave Function Theory (WFT) to model and interpret photoelectron spectra of adsorbed halogenated species on ice surfaces at the core level with the highest accuracy possible. </p><p>We make use of an embedding approach utilizing full quantum mechanics to divide the system into subunits that will be treated at different levels of theory [3].</p><p>The goal is to determine core electron binding energies and the associated chemical shifts for the adsorbed halogenated species such as molecular HCl and the dissociated form Cl- at the surface and within the uppermost bulk layer of the ice respectively [4]. The core energy shifts are compared to the data derived from the XPS spectra [4].</p><p>We show that the use of a fully quantum mechanical embedding method, to treat solute-solvent systems is computationally efficient, yet accurate enough to determine the electronic properties of the solute system (halide ion) as well as the long-range effects of the solvent environment (ice).</p><p>We acknowledge support by the French government through the Program “Investissement d'avenir” through the Labex CaPPA (contract ANR-11-LABX-0005-01) and I-SITE ULNE project OVERSEE (contract ANR-16-IDEX-0004), CPER CLIMIBIO (European Regional Development Fund, Hauts de France council, French Ministry of Higher Education and Research) and French national supercomputing facilities (grants DARI x2016081859 and A0050801859).</p><p> </p>

X-Ray photoelectron spectroscopy of monosubstituted perfluorobenzenes

1977 ◽  
Vol 55 (8) ◽  
pp. 1279-1284 ◽  
Author(s):  
Barry C. Trudell ◽  
S. James W. Price
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Atomic Charges ◽  
X Ray ◽  
Sophisticated Analysis ◽  
Charge Calculations

The gas phase X-ray photoelectron spectra, XPS, were observed for the series C6F5X (X = F, Cl, I, Br, H). Binding energies were determined from the spectra using the ESCAPLOT Program. Charge calculations were carried out using Equalization of Electronegativity, CNDO/2, and ACHARGE approaches on each molecule. The more sophisticated analysis leads to the following equation correlating the (C 1s) binding energies and the atomic charges qi[Formula: see text]

Photoluminescence of 10H-SiC

2016 ◽  
Vol 858 ◽  
pp. 269-273
Author(s):  
Anne Henry ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama
Keyword(s):  
Electron Microscope ◽  
Band Gap ◽  
Transmission Electron Microscope ◽  
Lower Energy ◽  
Free Exciton ◽  
Binding Energies ◽  
Photoluminescence Spectra ◽  
Transmission Electron ◽  
First Time

The photoluminescence of the near band gap emission of 10H-SiC is revealed for the first time and detected just below 3.0 eV. The crystallinity thus polytype of the sample is controlled with transmission electron microscope analyses and Laue diffraction. On the photoluminescence spectra up to eight sharp lines are associated to the non-phonon lines of the nitrogen bound exciton even if ten are expected in 10H-SiC. Phonon replicas of these non-phonon lines are observed at lower energy with energy separations similar than those in other hexagonal SiC polytypes. At moderate temperature free-exciton replicas are also observed which allow the determination of the excitonic band gap at 3020.6 meV, value in agreement with the hexagonality of 10H-SiC of 40%. The binding energies associated to the nitrogen bound-excitons are determined as well as the ionization energies of the nitrogen donors in the 10H-SiC polytype.

DENSITY FUNCTIONAL THEORY STUDY OF THE PHOTOELECTRON SPECTRA OF 5-METHYLTETRAZOLE

2013 ◽  
Vol 12 (01) ◽  
pp. 1250096 ◽  
Author(s):  
DELANO P. CHONG
Keyword(s):  
Density Functional ◽  
Slight Modification ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Core Electron ◽  
Functional Theory ◽  
Electron Ionization Spectrum ◽  
Core Electrons ◽  
Vertical Ionization Energies ◽  
Electron Binding Energies

The molecule 5-methyltetrazole (5MTZ) can exist in two taumeric forms. The vertical ionization energies (VIEs) of both valence and core electrons of both the tautomers are calculated with our established DFT procedures and compared with available experimental data. For the 2H-tautomer, the average absolute deviations (AADs) for the outer-valence VIEs and core-electron binding energies (CEBEs) from experiment are below 0.1 eV, while the AAD for the inner-valence VIEs is much larger at 0.4 eV. For the 1H-tautomer, no observed valence VIEs have been reported and the AAD for the calculated CEBEs is 0.2 eV. The assignment of the experimental core-electron ionization spectrum is confirmed, but our results suggest a slight modification of the assignment of the UV photoelectron spectrum of the 2H-tautomer.

Platelet Adhesion Study and Characteristic of Hydrogenated Carbon Films Synthesized by PIII-D

2005 ◽  
Vol 288-289 ◽  
pp. 323-326 ◽  
Author(s):  
Feng Wen ◽  
Nan Huang ◽  
H. Sun ◽  
Ping Yang ◽  
Jin Wang
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Raman Spectra ◽  
Room Temperature ◽  
Platelet Adhesion ◽  
Carbon Films ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Composition And Structure ◽  
Amorphous Hydrogenated Carbon

Amorphous hydrogenated carbon (a-C:H) thin films were deposited on silicon wafers and Ti6Al4V substrate using plasma ion immersion implantation and deposition (PIII-D) at room temperature (R.T.). The composition and structure of a-C:H films were employed by X-ray photoelectron spectra (XPS) and Raman spectra. Nano-indenter tests measured the hardness of the films. In addition, wettability and bloodcompatibility were investigated. In this paper, the effects of hydrogen content on structure, mechanical properties, surface wettability and haemocompatibility were discussed.

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