X-Ray Photoelectron Spectroscopic Studies of Palladium Dispersed on Carbon Surfaces Modified by Ion Beams and Plasmatic Oxidation

1995 ◽  
Vol 60 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Zdeněk Bastl
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Surface Coverage ◽  
Spectroscopic Studies ◽  
Core Level ◽  
Graphite Surface ◽  
Photoelectron Spectra ◽  
Surface Layers ◽  
X Ray ◽  
Core Level Binding Energy

The effects of ion bombardment and r.f. plasma oxidation of graphite surfaces on subsequent growth and electronic properties of vacuum deposited palladium clusters have been investigated by methods of X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy with X-ray excitation (XAES). Due to the significantly increased density of surface defects on which the nucleation process occurs the bulk value of the Pd 3d core level binding energy is achieved at higher surface coverage by palladium on bombarded surfaces than on ordered graphite. Angle resolved photoelectron spectra of oxidized graphite surfaces reveal significant embedding of oxygen in graphite surface layers. The C 1s and O 1s photoelectron spectra are consistent with presence of two major oxygen species involving C-O and C=O type linkages which are not homogeneously distributed within the graphite surface layers. Two effects were observed on oxidized surfaces: an increase of palladium dispersion and interaction of the metal clusters with surface oxygen groups. Using the simple interpretation of the modified Auger parameter the relaxation and chemical shift contributions to the measured Pd core level shifts are estimated. In the region of low surface coverage by palladium the effect of palladium-oxygen interaction on Pd core level binding energy exceeds the effects of increased dispersity.

scholarly journals Effect of electron correlation in the decomposition of core level binding energy shifts into initial and final state contributions

2019 ◽  
Vol 21 (18) ◽  
pp. 9399-9406 ◽  
Author(s):  
Marc Figueras ◽  
Carmen Sousa ◽  
Francesc Illas
Keyword(s):  
Binding Energy ◽  
Electron Correlation ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
Final State ◽  
X Ray ◽  
Core Level Binding Energy

The influence of electron correlation into the decomposition of core level binding energy shifts, measured by X-ray photoelectron spectroscopy (XPS), into initial and final effects is analysed for a series of molecules where these effects are noticeable.

scholarly journals Relating X-Ray Photoelectron Spectroscopy Data to Chemical Bonding in MXenes

2021 ◽  
Author(s):  
Nestor Garcia-Romeral ◽  
Masoomeh Keyhanian ◽  
Angel Morales-Garcia ◽  
Francesc Illas
Keyword(s):  
Binding Energy ◽  
Chemical Bonding ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
Spectroscopy Data ◽  
X Ray ◽  
The Relationship ◽  
Core Level Binding Energy

The relationship between core level binding energy shifts (CLBEs), that can be experimentally determined by X-Ray Photoelectron Spectroscopy, and chemical bonding is analyzed for a series of MXenes, a new...

Intersubband Absorption in Gallium Arsenide Implanted with Silicon Negative Ions

2019 ◽  
Vol 19 (03) ◽  
pp. 1950019
Author(s):  
A. R. Yadav ◽  
S. K. Dubey ◽  
R. L. Dubey ◽  
N. Subramanyam ◽  
I. Sulania
Keyword(s):  
Gallium Arsenide ◽  
Binding Energy ◽  
Crystallite Size ◽  
Photoelectron Spectroscopy ◽  
Nir Spectroscopy ◽  
Negative Ions ◽  
Core Level ◽  
Photoelectron Spectra ◽  
Gaas Sample ◽  
X Ray

Gallium arsenide (GaAs) implanted with silicon forming intersubband of SiGaAs is a promising material for making novel electronic and optoelectronic devices. This paper is focused on finding optimum fluence condition for formation of intersubband of SiGaAs in GaAs sample after implantation with 50[Formula: see text]keV silicon negative ions with fluences varying between [Formula: see text] and [Formula: see text] ions cm[Formula: see text]. The GaAs samples were investigated using X-ray photoelectron spectroscopy (XPS), UV-Vis.-NIR spectroscopy and X-ray diffraction (XRD) techniques. The X-ray photoelectron spectra for unimplanted sample showed peaks at binding energy of 18.74[Formula: see text]eV and 40.74[Formula: see text]eV indicating Ga3d and As3d core level, whereas the corresponding core level peaks for implanted sample were observed at binding energy of 19.25[Formula: see text]eV and 41.32[Formula: see text]eV. The shift in Ga3d and As3d core levels towards higher binding energy side in the implanted sample with respect to unimplanted sample were indicative of change in chemical state environment of Ga–As bond. The relative atomic percentage concentration of elemental composition measured using casa XPS software showed change in As/Ga ratio from 0.89 for unimplanted sample to 1.13 for sample implanted with the fluence of [Formula: see text] ion cm[Formula: see text]. The UV-Vis-NIR spectra showed absorption band between 1.365[Formula: see text]eV and 1.375[Formula: see text]eV due to the formation of intersubband of SiGaAs for fluences greater than [Formula: see text] ion cm[Formula: see text]. The GaAs crystallite size calculated using Brus formula was found to vary between 162[Formula: see text]nm and 540[Formula: see text]nm, respectively. The XRD spectra showed the presence of Bragg’s peak at 53.98∘ indicating (311) silicon reflection. The silicon crystallite size determined from full width at half maxima (FWHM) of (311) XRD peak was found to vary between 110[Formula: see text]nm and 161[Formula: see text]nm, respectively.

X-ray Photoelectron Spectroscopy of Surface Layers of Faceted Zinc Oxide Nanorods

2021 ◽  
Vol 26 (6) ◽  
pp. 481-490
Author(s):  
Z.V. Shomakhov ◽  
◽  
S.S. Nalimova ◽  
A.A. Bobkov ◽  
V.A. Moshnikov ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectra ◽  
Zinc Oxide Nanorods ◽  
Hydroxyl Groups ◽  
Surface Layers ◽  
Defective Structure ◽  
X Ray ◽  
Oxide Nanorods

The control of the nanomaterials surface’s hydrophilic properties is of interest for various applications, including optics, photocatalysis, and spintronics. In this work, techniques for designing the defective structure of the surface layers of faceted zinc oxide nanorods during sacrificial doping with iodine by hydrothermal synthesis were considered. The features of the chemical composition of the surface of the obtained layers were studied using X-ray photoelectron spectroscopy (XPS). It was found that peaks corresponding to the binding energy of iodine were not observed in the X-ray photoelectron spectra. An additional peak with a binding energy of 531.8 eV, corresponding to the oxygen of OH groups, was observed in the O 1s level spectrum for zinc oxide nanorods doped with iodine. During the heat treatment of the synthesized layers, iodine evaporates, which leads to a change in the surface composition and an increase in the oxygen content of the surface hydroxyl groups. A model has been proposed to explain the experimental results. It has been established that XPS techniques are effective for analyzing the defective surface structure of functional layers based on faceted zinc oxide nanorods.

The X-ray photoelectron spectroscopy of ancient murals in the tombs at Beni Hasan, Egypt

1987 ◽  
Vol 65 (5) ◽  
pp. 1058-1064 ◽  
Author(s):  
K. M. Wilson-Yang ◽  
George Burns
Keyword(s):  
Photoelectron Spectroscopy ◽  
Archaeological Site ◽  
Photoelectron Spectra ◽  
Surface Layers ◽  
X Ray ◽  
The Past ◽  
Mural Paintings ◽  
Adsorption Of Water ◽  
Aluminium Silicates ◽  
Trace Components

The once colourful mural paintings at the Beni Hasan tombs (ca. 2100 B.C.), an important Egyptian archaeological site, are covered with an obscuring grey deposit. Qualitative observations made over the past 150 years were assembled and correlated with each other by us. Cumulatively, they indicate that recently the development of this layer has accelerated. To study this surface degradation, X-ray photoelectron spectra of fragments from the painted walls have been collected. Empirical XPS sensitivity factors have been employed to treat the data semiquantitatively. Three types of surfaces were identified. The first surface consists of CaCO3 and SiO2 as major constituents, and was the only surface identified previously. Our XPS data indicate that it also contains Al2O3, NaCl, MgO, sulphates, and phosphates as minor and trace components. The second surface consists predominantly of aluminium silicates. The third surface consists mostly of calcium carbonate. A preliminary mechanism for opaque layer formation is proposed herein. It suggests that the principal physicochemical processes are adsorption of water in the presence of carbon dioxide, followed by dissolution of the substrate walls upon which the murals were painted. This mechanism is consistent with our finding that mural deterioration is recent; it also indicates that deterioration is progressive, continuous, and cumulative. Further experiments are designed to verify the proposed mechanism. Two mechanisms proposed earlier are found to be inconsistent with at least some of our findings. Relatively recent efforts in removing obtrusive surface layers with dilute HCl were found to be performed carefully; there was no evidence of excess chlorides on cleaned surfaces. However, this finding does not provide a guarantee that murals were undamaged by HCl below the surface. It does suggest that progressive damage due to the formation of hygroscopic CaCl2 on the surface has been avoided.

X-RAY PHOTOELECTRON STUDY OF Bi2Sr2CaCu2-xCoxO~8

1999 ◽  
Vol 13 (13) ◽  
pp. 1655-1662
Author(s):  
N. K. MAN ◽  
KAMLESH KUMARI ◽  
S. VENKATESH ◽  
T. D. HIEN ◽  
N. K. SINH ◽  
...  
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Hole Concentration ◽  
Core Level ◽  
Spectroscopy Study ◽  
Cobalt Doping ◽  
X Ray ◽  
Co Concentration ◽  
Photoelectron Study

An X-ray photoelectron spectroscopy study has been performed on well characterized Bi 2 Sr 2 CaCu 2-x Co x O ~8 (x=0, 0.02 and 0.1) samples. There is a shift in the Sr binding energy with Co concentration, which is related to the change in T c . This relationship can be understood by the change of hole concentration in the CuO 2 planes as a result of Cobalt doping. The results of Bi 4f and Co 2p core level spectra are also discussed in detail.

X-ray Photoelectron and UV Photoyield Spectroscopic Studies on Structural and Electronic Properties of SrxBiyTa2O9 Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Mitsue Takahashi ◽  
Minoru Noda ◽  
Masanori Okuyama
Keyword(s):  
Photoelectron Spectroscopy ◽  
Annealed Film ◽  
Spectroscopic Studies ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Additional Annealing ◽  
Structural And Electronic Properties ◽  
Before And After ◽  
Annealing Effects ◽  
Rapid Shift

ABSTRACTPhotoelectron spectra by X-ray photoelectron spectroscopy (XPS) and UV-photoyield spectroscopy (UV-PYS) have been analyzed to study O2-annealing effects on band diagrams of ferroelectric SrxBiyTa 2O9 (SBT) thin films deposited by pulsed laser deposition (PLD) and metalorganic dcecomposition (MOD) methods. XPS studies on the annealed PLD-SBT film has shown a rapid shift in its Bi 4f core peaks from the oxidized to the metallic ones, as the film suffer Ar+ bombardment. Surface of the annealed film has exhibited lower Fermi level than the as-deposited one in UV-PYS. The result suggests O2-annealing can suppress leakage current through PLD-SBT films. The UV-PYS studies on MOD-SBT have shown almost the intrinsic Fermi levels before and after the additional annealing. The XPS studies have shown that the additional annealing is not effective to improve stabilities of (Bi2O2)2+ layers, once the film is baked and crystallized.

ELECTRONIC STRUCTURE OF AgCd2GaS4

2007 ◽  
Vol 14 (03) ◽  
pp. 403-409 ◽  
Author(s):  
V. V. ATUCHIN ◽  
V. G. KESLER ◽  
O. V. PARASYUK
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Comparative Analysis ◽  
Binding Energy ◽  
Chemical Shift ◽  
Chemical Bonding ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
X Ray ◽  
Core Level Binding Energy

The electronic structure of AgCd 2 GaS 4 crystal has been studied with X-ray photoelectron spectroscopy (XPS). Chemical bonding effects have been observed by comparative analysis of binding energies of element core levels and crystal structure of AgCd 2 GaS 4 and several ternary sulfides. It has been shown for Ga-bearing sulfides that the increase of mean chemical bond length between gallium and sulfur ions is directly related to the decrease of chemical shift of cation core level binding energy.

Impurities in SiO2: Atomic States of Phosphorus and Arsenic

1986 ◽  
Vol 82 ◽  
Author(s):  
H. E. Rhodes ◽  
G. Apai
Keyword(s):  
Binding Energy ◽  
Silicon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
X Ray ◽  
Impurity Atoms ◽  
Atomic States ◽  
Energy Signal ◽  
State 1

ABSTRACTWe have studied the atomic states of arsenic (As) and phosphorus (P) in SiO2 using X-ray photoelectron spectroscopy (XPS). Silicon dioxide implanted with As or P shows multiple XPS core level peaks corresponding to the impurity atoms located in two distinct atomic sites. The binding energies of the two arsenic 3d core levels occur at 45.8 and 42.3 eV and the two phosphorus 2p core levels occur at 134.7 and 130.3 eV. When the implanted oxides are annealed in an oxygen ambient between 900°C and 950°C, only the highbinding- energy peaks of P and As are observed. This identifies the highbinding- energy core level peaks as being associated with the impurity (P or As) on silicon sites. Annealing in nitrogen at 950° C results in an increase in the low-binding-energy signal. The low-binding-energy peaks are associated with the impurity (P or As) bonded to silicon neighbors. The relative amounts of dopants in silicon and oxygen sites depend on ambient purity and processing details. Reference to previous work shows that the presence of As or P on silicon sites in SiO2 corresponds to a fast diffusing state whereas As or P on oxygen sites corresponds to a slow diffusing state [1].

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