scholarly journals Density Functional Theory Study on Defect Feature of AsGaGaAsin Gallium Arsenide

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Deming Ma ◽  
Xi Chen ◽  
Hongbo Qiao ◽  
Wei Wang ◽  
Wei Shi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Gallium Arsenide ◽  
Conduction Band ◽  
Density Functional ◽  
Crystal Surface ◽  
Deep Level ◽  
Donor Level ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Formation Energies

We investigate the defect feature ofAsGaGaAsdefect in gallium arsenide clusters in detail by using first-principles calculations based on the density functional theory (DFT). Our calculations reveal that the lowest donor level ofAsGaGaAsdefect on the gallium arsenide crystal surface is 0.85 eV below the conduction band minimum, while the lowest donor level of theAsGaGaAsdefect inside the gallium arsenide bulk is 0.83 eV below the bottom of the conduction band, consistent with gallium arsenide EL2 defect level of experimental value (Ec-0.82 eV). This suggests thatAsGaGaAsdefect is one of the possible gallium arsenide EL2 deep-level defects. Moreover, our results also indicate that the formation energies of internalAsGaGaAsand surfaceAsGaGaAsdefects are predicted to be around 2.36 eV and 5.54 eV, respectively. This implies that formation ofAsGaGaAsdefect within the crystal is easier than that of surface. Our results offer assistance in discussing the structure of gallium arsenide deep-level defect and its effect on the material.

Deep Level Formation in Undoped and Oxygen-Doped GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
J. M. Gregie ◽  
R. Y. Korotkov ◽  
B. W. Wessels
Keyword(s):  
Density Functional Theory ◽  
Steady State ◽  
Vapor Phase ◽  
Density Functional ◽  
Deep Level ◽  
Deep Level Defect ◽  
Functional Theory ◽  
Organic Vapor ◽  
Metal Organic ◽  
Formation Energies

ABSTRACTDeep level defects in oxygen doped GaN grown by metal-organic vapor phase epitaxy were investigated. Using steady-state photocapacitance (SSPC) spectroscopy, three deep levels with optical ionization energies of 1.0, 1.4, and 3.25 eV were observed in both nominally undoped and oxygen-doped samples. The total deep level defect concentrations ranged from 6 × 1015 cm-3 in undoped films to 3 × 1016 cm-3 in oxygen-doped films. The concentration of the 3.25 eV level defect increased upon oxygen doping, while the concentrationof the 1.0 and 1.4 eV levels were essentially dopant independent. From the measured concentrations the formation energies of the defects were calculated and compared to energies calculated using density functional theory.

The Modification of Anatase TiO2 (001) Surface by N or S Atom: A DFT Investigation

2014 ◽  
Vol 941-944 ◽  
pp. 588-592
Author(s):  
Zong Bao Li ◽  
Xia Wang
Keyword(s):  
Density Functional Theory ◽  
Visible Light ◽  
Electronic Structures ◽  
Density Functional ◽  
Light Response ◽  
Functional Theory ◽  
Visible Light Response ◽  
The Density Functional Theory ◽  
Elemental Doping ◽  
Formation Energies

The electronic of S-doped and N-doped anatase TiO2(001) surfaces were investigated using the density functional theory (DFT). Substitutional and interstitial configurations of N and S atoms doped in anatase TiO2(001) surface and sub-surface at different sites were considered and all the formation energies were obtained. The perfect strutures of atoms doping were obstained by formation energies comparisions. The electronic structures of the results indicated that the elemental doping has much more efficient and stable photocatalyst than the pristine one, which narrowed the band gap of TiO2and improved its visible-light response activity.

scholarly journals Electron-phonon interaction in In-induced √7 ×√3 structures on Si(111) from first-principles

2021 ◽  
Author(s):  
I. Yu. Sklyadneva ◽  
Rolf Heid ◽  
Pedro Miguel Echenique ◽  
Evgueni Chulkov
Keyword(s):  
Density Functional Theory ◽  
Double Layer ◽  
First Principles ◽  
Linear Response ◽  
Density Functional ◽  
Single Layer ◽  
Phonon Interaction ◽  
Functional Theory ◽  
Electron Phonon Interaction ◽  
The Density Functional Theory

Electron-phonon interaction in the Si(111)-supported rectangular √(7 ) ×√3 phases of In is investigated within the density-functional theory and linear-response. For both single-layer and double-layer √(7 ) ×√3 structures, it...

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

A trinuclear chromium(III) chlorocarbyne

2021 ◽  
Author(s):  
Takashi Kurogi ◽  
Keiichi Irifune ◽  
Takahiro Enoki ◽  
Kazuhiko Takai
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Terminal Alkynes ◽  
Functional Theory ◽  
The Density Functional Theory

Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(III) carbyne [CrCl(thf)2)]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The density functional theory...

Boron nitride zigzag nanoribbons: optimal thermoelectric systems

2015 ◽  
Vol 17 (34) ◽  
pp. 22448-22454 ◽  
Author(s):  
K. Zberecki ◽  
R. Swirkowicz ◽  
J. Barnaś
Keyword(s):  
Density Functional Theory ◽  
Boron Nitride ◽  
Density Functional ◽  
Thermoelectric Effects ◽  
Functional Theory ◽  
Thermoelectric Systems ◽  
The Density Functional Theory ◽  
Boron Nitride Nanoribbons

Conventional and spin related thermoelectric effects in zigzag boron nitride nanoribbons are studied theoretically within the Density Functional Theory (DFT) approach.

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