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

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.

1995 ◽  
Vol 60 (3) ◽  
pp. 383-392 ◽  
Author(s):  
Zdeněk Bastl

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.


2021 ◽  
Author(s):  
Nestor Garcia-Romeral ◽  
Masoomeh Keyhanian ◽  
Angel Morales-Garcia ◽  
Francesc Illas

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...


1999 ◽  
Vol 13 (13) ◽  
pp. 1655-1662
Author(s):  
N. K. MAN ◽  
KAMLESH KUMARI ◽  
S. VENKATESH ◽  
T. D. HIEN ◽  
N. K. SINH ◽  
...  

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.


2007 ◽  
Vol 14 (03) ◽  
pp. 403-409 ◽  
Author(s):  
V. V. ATUCHIN ◽  
V. G. KESLER ◽  
O. V. PARASYUK

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.


1986 ◽  
Vol 82 ◽  
Author(s):  
H. E. Rhodes ◽  
G. Apai

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].


2019 ◽  
Vol 19 (03) ◽  
pp. 1950019
Author(s):  
A. R. Yadav ◽  
S. K. Dubey ◽  
R. L. Dubey ◽  
N. Subramanyam ◽  
I. Sulania

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.


Author(s):  
S.M. Widstrand ◽  
K.O. Magnusson ◽  
L.S.O. Johansson ◽  
E. Moons ◽  
M. Gurnett ◽  
...  

We report on a high-resolution x-ray photoelectron spectroscopy (HRXPS) study using synchrotron radiation, for the identification of the core level binding energies of Ga 3d and N 1s, from a stoichiometric Ga-polar GaN(0001)-1×1 sample.Three surface shifted components were found on the stoichiometric surface for the Ga 3d feature. The first surface shifted component has a higher binding energy of 0.85 eV, and is interpreted as surface Ga with one of the N bonds replaced by an empty dangling bond. This structure is belonging to the stoichiometric clean and ordered Ga-polar GaN(0001)-1×1 surface. The second, with a binding energy relative the bulk of −0.76 eV, is interpreted as Ga with one of the bonds to a Ga atom, which indicates a slight excess of Ga on the surface. The third surface shifted component is shifted by 2.01 eV and is related to gallium oxide in different configurations.The N 1s feature is complex with five surface shifted components relative the bulk were found. Two components with binding energy shifts of −0.54 eV and 0.47 eV are interpreted as surface shifted core levels from the stoichiometric, clean Ga-polar GaN(0001)-1×1 surface.We also analysed the Ga 3d spectrum after deposition of 1.5 ML of Ga on a stoichiometric surface. The surface shift for the Ga 3d5/2 component from the Ga overlayer is −1.74 eV relative the bulk GaN.The C 1s and O 1s core levels from remaining surface contamination have also been line shaped analysed and show complex structures.


Sign in / Sign up

Export Citation Format

Share Document