An Electrochemical Study of Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
J. D. L'ecuyer ◽  
J. P. G. Farr
Keyword(s):  
Charge Transfer ◽  
Porous Silicon ◽  
Surface Chemistry ◽  
Valence Band ◽  
Surface State ◽  
Field Enhancement ◽  
Valence Band Edge ◽  
Adsorption Sites ◽  
Impedance Characteristics ◽  
Geometrical Field

ABSTRACTThe I-V and impedance characteristics of p and n-type silicon electrodes in HF solutions have been determined. Three different I-V regimes are observed, one of which is associated with the on-set of localized dissolution. The formation of porous silicon takes place via a surface state mediated charge transfer mechanism. The position of the main recombination-generation center is estimated at 400 mV above the valence band edge. Localized dissolution is initiated at or close to active adsorption sites. It is then favoured because of geometrical field enhancement effects. Porous silicon has a surface chemistry that can be significant in luminescence.

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).

Valence Band Edge Shifts and Charge-transfer Dynamics in Li-Doped NiO Based p-type DSSCs

2016 ◽  
Vol 188 ◽  
pp. 309-316 ◽  
Author(s):  
Lifang Wei ◽  
Linpeng Jiang ◽  
Shuai Yuan ◽  
Xin Ren ◽  
Yin Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Valence Band ◽  
Band Edge ◽  
Valence Band Edge ◽  
Charge Transfer Dynamics ◽  
P Type

scholarly journals Calculation of Band Offsets of Mg(OH)2-Based Heterostructures

2021 ◽  
Vol 2 (3) ◽  
pp. 274-283
Author(s):  
Masaya Ichimura
Keyword(s):  
Solar Cells ◽  
Valence Band ◽  
Dye Sensitized Solar Cells ◽  
Band Alignment ◽  
First Principles Calculation ◽  
Band Edge ◽  
Level Energy ◽  
Type I ◽  
Valence Band Edge ◽  
Generalized Gradient

The band alignment of Mg(OH)2-based heterostructures is investigated based on first-principles calculation. (111)-MgO/(0001)-Mg(OH)2 and (0001)-wurtzite ZnO/(0001)-Mg(OH)2 heterostructures are considered. The O 2s level energy is obtained for each O atom in the heterostructure supercell, and the band edge energies are evaluated following the procedure of the core-level spectroscopy. The calculation is based on the generalized gradient approximation with the on-site Coulomb interaction parameter U considered for Zn. For MgO/Mg(OH)2, the band alignment is of type II, and the valence band edge of MgO is higher by 1.6 eV than that of Mg(OH)2. For ZnO/Mg(OH)2, the band alignment is of type I, and the valence band edge of ZnO is higher by 0.5 eV than that of Mg(OH)2. Assuming the transitivity rule, it is expected that Mg(OH)2 can be used for certain types of heterostructure solar cells and dye-sensitized solar cells to improve the performance.

scholarly journals Determination of the valence band edge of Fe oxide nanoparticles dispersed in aqueous solution through resonant photoelectron spectroscopy from a liquid microjet

2021 ◽  
Author(s):  
Giorgia Olivieri ◽  
Gregor Kladnik ◽  
Dean Cvetko ◽  
Matthew A. Brown
Keyword(s):  
Aqueous Solution ◽  
Electronic Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Band Edge ◽  
Photoemission Spectroscopy ◽  
Oxide Nanoparticles ◽  
Valence Band Edge ◽  
Resonant Photoemission

The electronic structure of hydrated nanoparticles can be unveiled by coupling a liquid microjet with a resonant photoemission spectroscopy.

scholarly journals Defects in SiC for Quantum Computing

MRS Advances ◽  
2019 ◽  
Vol 4 (40) ◽  
pp. 2217-2222
Author(s):  
Renu Choudhary ◽  
Rana Biswas ◽  
Bicai Pan ◽  
Durga Paudyal
Keyword(s):  
Band Gap ◽  
Valence Band ◽  
Density Functional ◽  
Single Photon ◽  
Band Edge ◽  
Valence Band Edge ◽  
Dangling Bonds ◽  
Defect Levels ◽  
Formation Energies ◽  
Qubit Operation

AbstractMany novel materials are being actively considered for quantum information science and for realizing high-performance qubit operation at room temperature. It is known that deep defects in wide-band gap semiconductors can have spin states and long coherence times suitable for qubit operation. We theoretically investigate from ab-initio density functional theory (DFT) that the defect states in the hexagonal silicon carbide (4H-SiC) are potential qubit materials. The DFT supercell calculations were performed with the local-orbital and pseudopotential methods including hybrid exchange-correlation functionals. Di-vacancies in SiC supercells yielded defect levels in the gap consisting of closely spaced doublet just above the valence band edge, and higher levels in the band gap. The divacancy with a spin state of 1 is charge neutral. The divacancy is characterized by C-dangling bonds and a Si-dangling bonds. Jahn-teller distortions and formation energies as a function of the Fermi level and single photon interactions with these defect levels will be discussed. In contrast, the anti-site defects where C, Si are interchanged have high formation energies of 5.4 eV and have just a single shallow defect level close to the valence band edge, with no spin. We will compare results including the defect levels from both the electronic structure approaches.

Core Level Shifts and Grain Boundary Cohesion

1998 ◽  
Vol 4 (S2) ◽  
pp. 766-767
Author(s):  
D. A. Muller
Keyword(s):  
Charge Transfer ◽  
Valence Band ◽  
Core Level ◽  
Level Shift ◽  
The Core ◽  
Metallic Interfaces ◽  
Level Shifts ◽  
Electron Energy Loss ◽  
Valence Band Width

The role of core level shifts at metallic interfaces has often been ignored in electron energy loss spectroscopy (EELS) even though very small changes in bond length can lead to large core level shifts. However, the popular interpretation of core level shifts as measures of charge transfer is highly problematic. For instance, in binary alloys systems, the core level shifts can be the same sign for both atomic constituents[l]. The simple interpretation would require that both atomic species had lost or gained charge. Further, the signs of the core level shifts can be opposite to those expected from electronegativity arguments[2]. A core level shift (CLS) is still possible, even when no charge transfer occurs. As illustrated in Fig. 1, if the valence band width is increased, the position of the center of the valence band with respect to the Fermi energy will change (as the number of electrons remains unchanged).

Conduction and valence band edge properties of hexagonal InN characterized by optical measurements

2006 ◽  
Vol 3 (6) ◽  
pp. 1850-1853 ◽  
Author(s):  
Y. Ishitani ◽  
W. Terashima ◽  
S. B. Che ◽  
A. Yoshikawa
Keyword(s):  
Valence Band ◽  
Optical Measurements ◽  
Band Edge ◽  
Valence Band Edge

Down-shifting emission by charge transfer band in porous silicon infiltrated with Eu3+ and Gd3+ ions

2018 ◽  
Vol 120 ◽  
pp. 588-597
Author(s):  
Z. Lazcano ◽  
R. Silva ◽  
U. Salazar-Kuri ◽  
J. Arriaga ◽  
O. Meza
Keyword(s):  
Charge Transfer ◽  
Porous Silicon ◽  
Charge Transfer Band
Sign in / Sign up

Export Citation Format

Share Document