First-Principles Calculations Of Diffusion Of Chlorine Atoms In GaAs

1996 ◽  
Vol 442 ◽  
Author(s):  
Takahisa Ohno ◽  
Taizo Sasaki ◽  
Akihito Taguchi
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
First Principles ◽  
Interstitial Site ◽  
High Electron ◽  
Chlorine Atoms ◽  
Tetrahedral Interstitial Site ◽  
Bond Center ◽  
Cl Atom ◽  
Center Site

AbstractThe properties of chlorine atoms in crystalline GaAs, such as stable configurations, migration paths, charge-state effects, and interaction with dopant atoms are theoretically investigated. The calculations are based on the local density functional theory using first-principles pseudopotentials in a supercell geometry. We determine the stable charge state of an isolated Cl atom as a function of the Fermi energy. When the Fermi level is situated at the top of the valence band of GaAs, the Cl atom occupies preferentially the bond-center site of a Ga-As bond in the positive charge state. The Cl atom diffuses through the GaAs crystal via a path in the region of high electron density, with a fairly large energy barrier. When the Fermi level is at the bottom of the conduction band, the lowest-energy configuration of the Cl atom is the tetrahedral interstitial site in the negative charge state and the bond center site is very slightly higher in energy. In Si-doped GaAs, the C1 atom occupies the tetrahedral interstitial site with the substitutional Si donor atom as a nearest neighbor, forming a neutral Cl-Si complex. The Cl-Si complex is weak and easily dissociates into the isolated C1 and Si atoms in GaAs. A comparison will be made between the behavior of Cl and F atoms in GaAs.

Hydrogen in Crystalline Silicon under Compression and Tension

1989 ◽  
Vol 163 ◽  
Author(s):  
C.S. Nichols ◽  
D.R. Clarke
Keyword(s):  
Tensile Stress ◽  
Charge State ◽  
First Principles ◽  
Crystalline Silicon ◽  
Hydrogen Charge ◽  
Interstitial Site ◽  
Crystalline Lattice ◽  
Bond Center ◽  
Crack Tips ◽  
Center Site

AbstractThe behavior of hydrogen in crystalline silicon (c-Si) containing regions of compressive or tensile stress is important for understanding the solute’s interaction with dislocations, grain boundaries, and crack tips. A series of first-principles total-energy calculations probing the stable site for hydrogen as a function of its charge state, the Fermi level position, and the crystalline lattice constant has been performed. We find that the stable site for hydrogen depends critically on both pressure and on the hydrogen charge state. Furthermore, hydrogen is predicted to undergo a transition from an interstitial site to the bond-center site as a function of pressure.

scholarly journals First-Principles Assessment of the Structure and Stability of 15 Intrinsic Point Defects in Zinc-Blende Indium Arsenide

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 48 ◽  
Author(s):  
Qing Peng ◽  
Nanjun Chen ◽  
Danhong Huang ◽  
Eric Heller ◽  
David Cardimona ◽  
...  
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
Indium Arsenide ◽  
Point Defects ◽  
First Principles ◽  
Formation Energy ◽  
Fast Diffusion ◽  
Intrinsic Point Defects ◽  
Zinc Blende ◽  
Tetrahedral Sites

Point defects are inevitable, at least due to thermodynamics, and essential for engineering semiconductors. Herein, we investigate the formation and electronic structures of fifteen different kinds of intrinsic point defects of zinc blende indium arsenide (zb-InAs ) using first-principles calculations. For As-rich environment, substitutional point defects are the primary intrinsic point defects in zb-InAs until the n-type doping region with Fermi level above 0.32 eV is reached, where the dominant intrinsic point defects are changed to In vacancies. For In-rich environment, In tetrahedral interstitial has the lowest formation energy till n-type doped region with Fermi level 0.24 eV where substitutional point defects In A s take over. The dumbbell interstitials prefer < 110 > configurations. For tetrahedral interstitials, In atoms prefer 4-As tetrahedral site for both As-rich and In-rich environments until the Fermi level goes above 0.26 eV in n-type doped region, where In atoms acquire the same formation energy at both tetrahedral sites and the same charge state. This implies a fast diffusion along the t − T − t path among the tetrahedral sites for In atoms. The In vacancies V I n decrease quickly and monotonically with increasing Fermi level and has a q = − 3 e charge state at the same time. The most popular vacancy-type defect is V I n in an As-rich environment, but switches to V A s in an In-rich environment at light p-doped region when Fermi level below 0.2 eV. This study sheds light on the relative stabilities of these intrinsic point defects, their concentrations and possible diffusions, which is expected useful in defect-engineering zb-InAs based semiconductors, as well as the material design for radiation-tolerant electronics.

scholarly journals First-Principles Investigation of Atomic Hydrogen Adsorption and Diffusion on/into Mo-doped Nb (100) Surface

2018 ◽  
Vol 8 (12) ◽  
pp. 2466 ◽  
Author(s):  
Yang Wu ◽  
Zhongmin Wang ◽  
Dianhui Wang ◽  
Jiayao Qin ◽  
Zhenzhen Wan ◽  
...  
Keyword(s):  
First Principles ◽  
Atomic Hydrogen ◽  
Energy Barrier ◽  
Hydrogen Adsorption ◽  
Hydrogen Permeation ◽  
Diffusion Path ◽  
Interstitial Site ◽  
Octahedral Interstitial Site ◽  
Tetrahedral Interstitial Site ◽  
And Diffusion

To investigate Mo doping effects on the hydrogen permeation performance of Nb membranes, we study the most likely process of atomic hydrogen adsorption and diffusion on/into Mo-doped Nb (100) surface/subsurface (in the Nb12Mo4 case) via first-principles calculations. Our results reveal that the (100) surface is the most stable Mo-doped Nb surface with the smallest surface energy (2.75 J/m2). Hollow sites (HSs) in the Mo-doped Nb (100) surface are H-adsorption-favorable mainly due to their large adsorption energy (−4.27 eV), and the H-diffusion path should preferentially be HS→TIS (tetrahedral interstitial site) over HS→OIS (octahedral interstitial site) because of the correspondingly lower H-diffusion energy barrier. With respect to a pure Nb (100) surface, the Mo-doped Nb (100) surface has a smaller energy barrier along the HS→TIS pathway (0.31 eV).

Electronic Structure and Hyperfine Parameters for Hydrogen and Muonium in Silicon

1989 ◽  
Vol 163 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
Spin Density ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Muon Spin ◽  
Spin Rotation ◽  
Muon Spin Rotation ◽  
Hyperfine Parameters ◽  
Bond Center ◽  
Center Site

AbstractFirst-principles spin-density-functional calculations are used to evaluate hyperfine and superhyperfine parameters for hydrogen and muonium at various sites in the Si lattice. The results can be directly compared with values from muon-spin-rotation experiments, leading to an unambiguous identification of “anomalous muonium” with the bond-center site. The agreement found in this case instills confidence in the general use of spin-density-functional calculations for predicting hyperfine parameters of defects.

scholarly journals First-Principles Study on Various Point Defects Formed by Hydrogen and Helium Atoms in Tungsten

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Qiang Zhao ◽  
Zheng Zhang ◽  
Yang Li ◽  
Xiaoping Ouyang
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Formation Energy ◽  
Interstitial Site ◽  
First Principles Calculation ◽  
Hydrogen Atoms ◽  
Substitutional Site ◽  
Helium Atoms ◽  
Tetrahedral Interstitial Site ◽  
Formation Energies

The different point defects formed by two hydrogen atoms or two helium atoms in tungsten were investigated through first-principles calculation. The energetically favorable site for a hydrogen atom is tetrahedral interstitial site while substitutional site is the most preferred site for a helium atom. The formation energies of two hydrogen or helium atoms are determined by their positions, and they are not simply 2 times the formation energy of a single hydrogen or helium atom’s defect. After relaxation, two adjacent hydrogen atoms are away from each other while helium atoms are close to each other. The reasons for the interaction between two hydrogen or helium atoms are also discussed.

Atomic Hydrogen in GaN

1995 ◽  
Vol 378 ◽  
Author(s):  
Jürg Neugebauer ◽  
Chris G. Van de Walle
Keyword(s):  
Electronic Structure ◽  
Nitrogen Atom ◽  
Total Energy ◽  
Diffusion Barrier ◽  
First Principles ◽  
Atomic Hydrogen ◽  
Interstitial Site ◽  
Energy Calculations ◽  
Tetrahedral Interstitial Site ◽  
Cubic Gan

ABSTRACTBased on extensive first-principles total-energy calculations we study the electronic structure, atomic geometry and energetics of atomic hydrogen in cubic GaN. All charge states of hydrogen (H+, H0, H-) are examined. For H- the gallium tetrahedral interstitial site is energetically most stable. All other sites are much higher in energy, indicating a high diffusion barrier for H- in GaN. H+ favors positions on a sphere with a radius of ≈ 1 Å and a nitrogen atom in the center. Among these positions the nitrogen antibonding site is energetically most stable. An unexpectedly large negative-U effect (U = —2.5eV) indicates that H0 is unstable.

Effect of the alloying element titanium on the stability and trapping of hydrogen in pure vanadium: A first-principles study

2014 ◽  
Vol 28 (29) ◽  
pp. 1450207 ◽  
Author(s):  
Juan Hua ◽  
Yue-Lin Liu ◽  
Heng-Shuai Li ◽  
Ming-Wen Zhao ◽  
Xiang-Dong Liu
Keyword(s):  
Binary Alloy ◽  
First Principles ◽  
Density Functional ◽  
Interstitial Site ◽  
Alloying Element ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Tetrahedral Interstitial Site ◽  
The Stability ◽  
Insight Into

With a first-principles method based on density functional theory, the effect of the alloying element titanium ( Ti ) on the thermodynamic stability and electronic structure of hydrogen ( H ) in pure vanadium ( V ) is investigated. The interactions between H and the vacancy and the defect solution energies in a dilute V – Ti binary alloy are calculated. The results show that: (i) a single H atom prefers to reside in a tetrahedral interstitial site in dilute V – Ti binary alloy systems; (ii) H atoms tend to bond at the vacancy sites; a mono-vacancy is shown to be capable of trapping three H atoms; and (iii) the presence of Ti in pure V can increase the H trapping energy and reduce the H trapping capability of the vacancy defects. This indicates that doping with Ti to form dilute V – Ti binary alloys can inhibit the solution for H , and thus suppress the retention of H . These results provide useful insight into V -based alloys as a candidate structural material in fusion reactors.

scholarly journals Hydrogen Transportation Behaviour of V–Ni Solid Solution: A First-Principles Investigation

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2603
Author(s):  
Jiayao Qin ◽  
Zhigao Liu ◽  
Wei Zhao ◽  
Dianhui Wang ◽  
Yanli Zhang ◽  
...  
Keyword(s):  
First Principles ◽  
Interstitial Site ◽  
Ni Doping ◽  
Octahedral Interstitial Site ◽  
Ni Addition ◽  
Solution Energy ◽  
Tetrahedral Interstitial Site ◽  
Materials Used ◽  
The Stability ◽  
Hydrogen Systems

Hydrogen embrittlement causes deterioration of materials used in metal–hydrogen systems. Alloying is a good option for overcoming this issue. In the present work, first-principles calculations were performed to systematically study the effects of adding Ni on the stability, dissolution, trapping, and diffusion behaviour of interstitial/vacancy H atoms of pure V. The results of lattice dynamics and solution energy analyses showed that the V–Ni solid solutions are dynamically and thermodynamically stable, and adding Ni to pure V can reduce the structural stability of various VHx phases and enhance their resistance to H embrittlement. H atoms preferentially occupy the characteristic tetrahedral interstitial site (TIS) and the octahedral interstitial site (OIS), which are composed by different metal atoms, and rapidly diffuse along both the energetically favourable TIS → TIS and OIS → OIS paths. The trapping energy of monovacancy H atoms revealed that Ni addition could help minimise the H trapping ability of the vacancies and suppress the retention of H in V. Monovacancy defects block the diffusion of H atoms more than the interstitials, as determined from the calculated H-diffusion barrier energy data, whereas Ni doping contributes negligibly toward improving the H-diffusion coefficient.

Effect of Boron and Hydrogen on the Electronic Structure of Ni3Al

1993 ◽  
Vol 319 ◽  
Author(s):  
N. Kioussis ◽  
H. Watanabe ◽  
R.G. Hemker ◽  
W. Gourdin ◽  
A. Gonis ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
First Principles ◽  
Electronic Structure Calculations ◽  
Interstitial Site ◽  
Octahedral Interstitial Site ◽  
Interstitial Region ◽  
Ordered Intermetallic ◽  
Lmto Method ◽  
Structure Calculations

AbstractUsing first-principles electronic structure calculations based on the Linear-Muffin-Tin Orbital (LMTO) method, we have investigated the effects of interstitial boron and hydrogen on the electronic structure of the L12 ordered intermetallic Ni3A1. When it occupies an octahedral interstitial site entirely coordinated by six Ni atoms, we find that boron enhances the charge distribution found in the strongly-bound “pure” Ni3AI crystal: Charge is depleted at Ni and Al sites and enhanced in interstitial region. Substitution of Al atoms for two of the Ni atoms coordinating the boron, however, reduces the interstitial charge density between certain atomic planes. In contrast to boron, hydrogen appears to deplete the interstitial charge, even when fully coordinated by Ni atoms. We suggest that these results are broadly consistent with the notion of boron as a cohesion enhancer and hydrogen as an embrittler.

scholarly journals Rich p -type-doping phenomena in boron-substituted silicene systems

2020 ◽  
Vol 7 (12) ◽  
pp. 200723
Author(s):  
Hai Duong Pham ◽  
Wu-Pei Su ◽  
Thi Dieu Hien Nguyen ◽  
Ngoc Thanh Thuy Tran ◽  
Ming-Fa Lin
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Charge Density ◽  
Electronic Properties ◽  
First Principles ◽  
Chemical Environment ◽  
First Principles Calculations ◽  
Density Distributions ◽  
Essential Properties ◽  
P Type

The essential properties of monolayer silicene greatly enriched by boron substitutions are thoroughly explored through first-principles calculations. Delicate analyses are conducted on the highly non-uniform Moire superlattices, atom-dominated band structures, charge density distributions and atom- and orbital-decomposed van Hove singularities. The hybridized 2 p z –3 p z and [2s, 2 p x , 2 p y ]–[3s, 3 p x , 3 p y ] bondings, with orthogonal relations, are obtained from the developed theoretical framework. The red-shifted Fermi level and the modified Dirac cones/ π bands/ σ bands are clearly identified under various concentrations and configurations of boron-guest atoms. Our results demonstrate that the charge transfer leads to the non-uniform chemical environment that creates diverse electronic properties.

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