The influence of nitrogen doping on the electronic structure of the valence and conduction band in TiO2

2019 ◽  
Vol 26 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Klaudia Wojtaszek ◽  
Anna Wach ◽  
Joanna Czapla-Masztafiak ◽  
Krzysztof Tyrala ◽  
Jacinto Sá ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Conduction Band ◽  
Emission Spectroscopy ◽  
Nitrogen Doping ◽  
Theoretical Calculations ◽  
Band Gap Energy ◽  
X Ray ◽  
Gap Energy ◽  
N Doping ◽  
X Ray Absorption

X-ray emission spectroscopy (XES) and X-ray absorption spectroscopy (XAS) provide a unique opportunity to probe both the highest occupied and the lowest unoccupied states in matter with bulk sensitivity. In this work, a combination of valence-to-core XES and pre-edge XAS techniques are used to determine changes induced in the electronic structure of titanium dioxide doped with nitrogen atoms. Based on the experimental data it is shown that N-doping leads to incorporation of the p-states on the occupied electronic site. For the conduction band, a decrease in population of the lowest unoccupied d-localized orbitals with respect to the d-delocalized orbitals is observed. As confirmed by theoretical calculations, the N p-states in TiO2 structure are characterized by higher binding energy than the O p-states which gives a smaller value of the band-gap energy for the doped material.

Bulk and Surface Electronic Structure of GaN Measured Using Angle-Resolved Photoemission, Soft X-ray Emission and Soft X-ray Absorption

1996 ◽  
Vol 449 ◽  
Author(s):  
Kevin E. Smith ◽  
Sarnjeet S Dhesi ◽  
Laurent-C. Duda ◽  
Cristian B Stagarescu ◽  
J. H. Guo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Absorption Spectra ◽  
Conduction Band ◽  
Brillouin Zone ◽  
Emission Spectra ◽  
Partial Density ◽  
High Symmetry ◽  
X Ray ◽  
X Ray Absorption

ABSTRACTThe electronic structure of thin film wurtzite GaN has been studied using a combination of angle resolved photoemission, soft x-ray absorption and soft x-ray emission spectroscopies. We have measured the bulk valence and conduction band partial density of states by recording Ga L- and N K- x-ray emission and absorption spectra. We compare the x-ray spectra to a recent ab initio calculation and find good overall agreement. The x-ray emission spectra reveal that the top of the valence band is dominated by N 2p states, while the x-ray absorption spectra show the bottom of the conduction band as a mixture of Ga 4s and N 2p states, again in good agreement with theory. However, due to strong dipole selection rules we can also identify weak hybridization between Ga 4s- and N 2p-states in the valence band. Furthermore, a component to the N K-emission appears at approximately 19.5 eV below the valence band maximum and can be identified as due to hybridization between N 2p and Ga 3d states. We report preliminary results of a study of the full dispersion of the bulk valence band states along high symmetry directions of the bulk Brillouin zone as measured using angle resolved photoemission. Finally, we tentatively identify a non-dispersive state at the top of the valence band in parts of the Brillouin zone as a surface state.

Electronic structure of NixTiSe2 (0.05 ≤ x ≤ 0.46) compounds with ordered and disordered Ni

2017 ◽  
Vol 19 (6) ◽  
pp. 4500-4506 ◽  
Author(s):  
A. S. Shkvarin ◽  
Yu. M. Yarmoshenko ◽  
A. I. Merentsov ◽  
Yu. M. Zhukov ◽  
A. A. Titov ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Absorption Spectroscopy ◽  
Theoretical Calculations ◽  
Electronic States ◽  
Intercalation Compounds ◽  
X Ray ◽  
Density Of Electronic States ◽  
X Ray Absorption

The electronic structure of NixTiSe2 intercalation compounds with disordered and ordered Ni atoms is studied using photoelectron, resonant photoelectron and X-ray absorption spectroscopy, theoretical calculations of the X-ray spectra and density of electronic states.

Electronic structure of (MePh3P)2[NiII(bdtCl2)2]·2(CH3)2SO and (MePh3P)[NiIII(bdtCl2)2] (bdtCl2 = 3,6-dichlorobenzene-1,2-dithiolate)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Julia Adamko Koziskova ◽  
Yu-Sheng Chen ◽  
Su-Yin Grass ◽  
Yu-Chun Chuang ◽  
I-Jui Hsu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Theoretical Calculations ◽  
Nickel Complexes ◽  
Oxidation States ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption ◽  
Bond Character ◽  
Density Modeling

High-resolution X-ray diffraction experiments, theoretical calculations and atom-specific X-ray absorption experiments were used to investigate two nickel complexes, (MePh3P)2[NiII(bdtCl2)2]·2(CH3)2SO [complex (1)] and (MePh3P)[NiIII(bdtCl2)2] [complex (2)]. Combining the techniques of nickel K- and sulfur K-edge X-ray absorption spectroscopy with high-resolution X-ray charge density modeling, together with theoretical calculations, the actual oxidation states of the central Ni atoms in these two complexes are investigated. Ni ions in two complexes are clearly in different oxidation states: the Ni ion of complex (1) is formally NiII; that of complex (2) should be formally NiIII, yet it is best described as a combination of Ni2+ and Ni3+, due to the involvement of the non-innocent ligand in the Ni—L bond. A detailed description of Ni—S bond character (σ,π) is presented.

Electronic Structure of Sulfur Studied by X-ray Absorption and Emission Spectroscopy

2009 ◽  
Vol 81 (15) ◽  
pp. 6516-6525 ◽  
Author(s):  
R. Alonso Mori ◽  
E. Paris ◽  
G. Giuli ◽  
S. G. Eeckhout ◽  
M. Kavčič ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Emission Spectroscopy ◽  
Absorption And Emission ◽  
X Ray ◽  
X Ray Absorption ◽  
Absorption And Emission Spectroscopy
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