Optical Properties of the Pb Center at the Si/SiO2 Interface

1985 ◽  
Vol 46 ◽  
Author(s):  
Arthur H. Edwards ◽  
W. Beall Fowler
Keyword(s):  
Valence Band ◽  
Conduction Band ◽  
Defect State ◽  
Polarization Effects ◽  
Unoccupied State ◽  
Cluster Calculations ◽  
Occupied State ◽  
Order Of Magnitude ◽  
Neutral Defect ◽  
Theoretical Results

AbstractWe present theoretical results for the optical prooerties of the Pb center at the Si/SiO2 interface. Using wave functions obtainec from semiempirical (MINDO/3) cluster calculations, we have calculated electric dipole matrix elements connecting the singly occupied (neutral) defect state to the unoccupied conduction-band-like states, as well as those connecting the occupied valence-band-like states to the singly occupied defect state and to the unoccupied defect state. We predict the absorption cross section for excitation from the valence band to the unoccupied state to be of order 10−19 cm2 and that for excitation from the valence band to the occupied state and from the occupied state to the conduction band to be an order of magnitude larger. We also predict that the absorption will in some cases be strongly dependent on the direction of the polarization. Effects of symmetry lowering in the oxide and of distortions in the silicon are discussed.

scholarly journals Conduction Band Engineering of Half-Heusler Thermoelectrics Using Orbital Chemistry

2022 ◽  
Author(s):  
Shuping Guo ◽  
Shashwat Anand ◽  
Madison K. Brod ◽  
Yongsheng Zhang ◽  
G. Jeffrey Snyder
Keyword(s):  
Electronic Properties ◽  
Valence Band ◽  
Conduction Band ◽  
Thermoelectric Materials ◽  
Band Engineering

Semiconducting half-Heusler (HH, XYZ) phases are promising thermoelectric materials owing to their versatile electronic properties. Because the valence band of half-Heusler phases benefits from the valence band extrema at several...

scholarly journals Влияние ионов неодима (III) на фотолюминесценцию сульфидов кадмия и цинка в полиакрилатной матрице

2022 ◽  
Vol 56 (2) ◽  
pp. 229
Author(s):  
В.П. Смагин ◽  
А.А. Исаева ◽  
Е.А. Шелепова
Keyword(s):  
Methyl Methacrylate ◽  
Valence Band ◽  
Conduction Band ◽  
Structural Defects ◽  
Excitation Spectra ◽  
Nanoscale Particles ◽  
Semiconductor Structures ◽  
Semiconductor Particles ◽  
Optically Transparent

Nanoscale particles ZnS:Nd3+, CdS:Nd3+ and (Zn,Cd)S:Nd3+ were synthesized and doped in a polymerizing methyl methacrylate medium during the production of optically transparent polyacrylate composites of the composition PMMA/ZnS:Nd3+, PMMA/CdS:Nd3+ and PMMA/(Zn,Cd)S:Nd3+. The excitation of photoluminescence (FL) and FL of semiconductor structures in composites is associated with the transition of electrons from the valence band to the conduction band and to the levels of structural defects of semiconductor particles, followed by recombination at these levels. Based on changes in the excitation spectra of FL and FL composites, assumptions are made about the structure of particles, the distribution of Nd3+ ions in it and their effect on photoluminescence.

POLARIZATION PROPERTIES OF SYNCHROTRON RADIATION IN THE STUDY OF ANISOTROPIC INSULATING CRYSTALS

2002 ◽  
Vol 09 (01) ◽  
pp. 469-472
Author(s):  
V. N. KOLOBANOV ◽  
I. A. KAMENSKIKH ◽  
V. V. MIKHAILIN ◽  
I. N. SHPINKOV ◽  
D. A. SPASSKY ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Energy Transfer ◽  
Synchrotron Radiation ◽  
Valence Band ◽  
Conduction Band ◽  
Electronic States ◽  
Absorption Region ◽  
New Information ◽  
Fundamental Absorption Region

The optical properties of a wide series of the tungstates with the scheelite and wolframite crystal structure at the threshold of the fundamental absorption region were studied. New information about the influence of the electronic states forming the bottom of the conduction band and the top of the valence band on the formation of emission centers and mechanisms of energy transfer to these centers was obtained.

XPS, AES AND UPS INVESTIGATION OF SnO2/Si AND DFT-BASED THEORETICAL STUDY WITHIN THE mBJ-GGA SCHEME

2020 ◽  
pp. 2050048
Author(s):  
A. MOKADEM ◽  
M. BOUSLAMA ◽  
B. KHAROUBI ◽  
A. OUERDANE ◽  
R. KHENATA ◽  
...  
Keyword(s):  
Valence Band ◽  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic Distribution ◽  
Complementary Techniques ◽  
Uv Photoelectron Spectroscopy ◽  
Theoretical Results

We investigate the growth performance of tin oxide on the Si substrate, achieved by spray pyrolysis using the sensitive analysis techniques X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). These complementary techniques confirm the growth of homogeneous SnO2 thin films. We also study the electronic distribution of the valence band of SnO2 theoretically using density functional theory (DFT). The chemical and physical properties of the material depend on the electron structure varying as a function of energy. The density of states (DOS) is calculated using the modified Becke–Johnson-Generalized Gradient Approximation (mBJ-GGA) in order to identify the electronic orbitals and the importance of their contribution to the electronic structure of the valence band. Furthermore, we use the experimental technique UV Photoelectron Spectroscopy (UPS) for studying the electronic distribution within the valence band and for validating the theoretical results of the density of states of SnO2/Si.

scholarly journals Photocatalytic properties of a new Z-scheme system BaTiO3/In2S3 with a core–shell structure

RSC Advances ◽  
2019 ◽  
Vol 9 (20) ◽  
pp. 11377-11384 ◽  
Author(s):  
Kaili Wei ◽  
Baolai Wang ◽  
Jiamin Hu ◽  
Fuming Chen ◽  
Qing Hao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Valence Band ◽  
Conduction Band ◽  
Shell Structure ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Core Shell ◽  
Valence Band Edge ◽  
Core Shell Structure ◽  
Positive Valence

It's highly desired to design an effective Z-scheme photocatalyst with excellent charge transfer and separation, a more negative conduction band edge (ECB) than O2/·O2− (−0.33 eV) and a more positive valence band edge (EVB) than ·OH/OH− (+2.27 eV).

scholarly journals Ab initioStudies of Electronic Structure of Defects in PbTe

2005 ◽  
Vol 864 ◽  
Author(s):  
Salameh Ahmad ◽  
Daniel Bilc ◽  
S.D. Mahanti ◽  
M.G. Kanatzidis
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Conduction Band ◽  
Density Of States ◽  
Resonance State ◽  
Interesting Case ◽  
The Other ◽  
Defect States ◽  
Strong Resonance ◽  
Structure Calculations

AbstractAb initioelectronics structure calculations have been carried out in a series of RPb2n-1Te2n, n=16, compounds to understand the nature of “defect” states introduced by R where R = vacancy, monovalent Na, K, Rb, Cs, Ag atoms and divalent Cd atoms. We find that the density of states (DOS) near the top of the valence band and the bottom of the conduction band get significantly modified. The Na atom seems to perturb this region least (ideal acceptor in PbTe) and the other monovalent atoms enhance the DOS near the top of the valence band. Cd is an interesting case, since it introduces a strong resonance state near the bottom of the conduction band.

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.

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