First-Principles Investigations of Hydrogen and Fluorine on Silicon Surfaces

1992 ◽  
Vol 259 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
First Principles ◽  
Etch Rate ◽  
State Of The Art ◽  
Interstitial Impurity ◽  
Silicon Surfaces ◽  
Hydrogen Solubility ◽  
First Principles Calculations ◽  
Energy Diagram

ABSTRACTState-of-the-art first-principles calculations allow detailed studies of the mechanisms by which hydrogen and fluorine interact with silicon. The results for hydrogen are presented in the form of an energy diagram which includes many different configurations. The theoretical values allow a discussion of issues such as hydrogen solubility, and desorption from a Si surface. For fluorine, we investigate the behavior as an interstitial impurity in the bulk, as well as Si-F interactions at or near the surface. A study of the insertion of F atoms into Si-Si bonds elucidates the microscopic mechanisms of etching, and the dependence of etch rate on doping. Thermodynamic aspects of HF etching are briefly discussed.

Atomic Structure of CaSi2/Si Interfaces

1989 ◽  
Vol 159 ◽  
Author(s):  
Chris G. Van De Walle
Keyword(s):  
Schottky Barrier ◽  
Atomic Structure ◽  
First Principles ◽  
State Of The Art ◽  
Interfacial Structure ◽  
First Principles Calculations ◽  
Barrier Heights

ABSTRACTThe CaSi2/Si interface is studied with state-of-the-art first-principles calculations. Various models for the interfacial structure are examined, in which the Ca atoms at the interface exhibit 5-, 6-, 7-, or 8-fold coordination. The structures with sevenfold coordination (as in bulk CaSi2) have the lowest energy. However, the sixfold- and eightfold-coordinated structures are only ∼0.1 eV higher in energy. Schottky barrier heights are briefly discussed.

The stability, electronic structure, and optical absorption of boron-nitride diamondoids predicted with first-principles calculations

2018 ◽  
Vol 20 (28) ◽  
pp. 19188-19194 ◽  
Author(s):  
Weiwei Gao ◽  
Linda Hung ◽  
Serdar Ogut ◽  
James R. Chelikowsky
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Boron Nitride ◽  
Optical Absorption ◽  
Computational Methods ◽  
First Principles ◽  
State Of The Art ◽  
First Principles Calculations ◽  
The Stability

The stability, electronic structure, and optical properties of six boron-nitride diamondoids are systematically studied with state-of-the-art computational methods and compared with diamondoids.

Role Of Hydrogen And Hydrogen Complexes In Doping Of Gan

1996 ◽  
Vol 423 ◽  
Author(s):  
Jörg Neugebauer ◽  
Chris G. Van de wallei
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
State Of The Art ◽  
Growth Conditions ◽  
Fundamental Difference ◽  
First Principles Calculations ◽  
Native Defects ◽  
In Doping ◽  
And Migration

AbstractWe have calculated electronic structure, energetics and migration for hydrogen and hydrogen complexes in GaN employing state-of-the-art first-principles calculations. Using these results in combination with previous detailed investigations about native defects we have calculated the concentration of hydrogen and dopants for different growth conditions. Our results reveal a fundamental difference in the behavior of hydrogen in p-type and n-type material. In particular, we explain why hydrogen has little effect on donor impurities and why H concentrations are low in n-type GaN. We discuss why hydrogen is beneficial for acceptor incorporation in GaN, and identify the limitations of this process.

Theory of Point Defects and Complexes in GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
Jörg Neugebauer ◽  
Chris G. Van de Walle
Keyword(s):  
First Principles ◽  
State Of The Art ◽  
Growth Parameters ◽  
Free Carrier ◽  
First Principles Calculations ◽  
Acceptor Doping ◽  
Native Defects ◽  
Chemical Potentials ◽  
Insight Into

ABSTRACTWe have studied the electronic and energetic properties of native defects, impurities and complexes in GaN applying state-of-the-art first-principles calculations. An analysis of the numerical results gives direct insight into defect concentrations and impurity solubility with respect to growth parameters (temperature, chemical potentials) and into the mechanisms limiting the doping levels in GaN. We show how compensation and passivation by native defects or impurities, solubility issues, and incorporation of dopants on other sites influence the acceptor doping levels. The role of hydrogen in enhancing the p-type doping is explained in detail. We also discuss the mechanisms responsible for the experimentally observed limitation of the free-carrier concentration in p-type GaN.

Theory of Defects in Wide-Band-Gap Semiconductors

1995 ◽  
Vol 378 ◽  
Author(s):  
Chris G Van de Walle ◽  
Jörg Neugebauer
Keyword(s):  
Band Gap ◽  
First Principles ◽  
State Of The Art ◽  
Wide Band ◽  
First Principles Calculations ◽  
Wide Band Gap ◽  
Native Defects ◽  
In Doping ◽  
Wide Band Gap Semiconductors

AbstractWe discuss the application of state-of-the-art first-principles calculations to the problem of defects, impurities, and doping levels in semiconductors. Since doping problems are of particular relevance in wide-band-gap materials, we focus here on studies of ZnSe and GaN. For ZnSe, we discuss our latest insights in the influence of compensation and dopant solubility on the experimentally observed limitation of the free carrier concentration in p-type ZnSe. For GaN, we focus on the role of native defects in doping or compensation of the material, with particular emphasis on the n-type conductivity of as-grown GaN.

scholarly journals First-Principles Calculations of Hybrid Inorganic-Organic Interfaces: From State-of-the-Art to Best Practice

2021 ◽  
Author(s):  
Oliver Hofmann ◽  
Egbert Zojer ◽  
Lukas Hörmann ◽  
Andreas Jeindl ◽  
Reinhard Maurer
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Best Practice ◽  
State Of The Art ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Inorganic P ◽  
Organic Hybrid ◽  
Organic Interfaces

The computational characterization of inorganic-organic hybrid interfaces is arguably one of the technically most challenging applications of density functional theory. Due to the fundamentally different electronic properties of the inorganic...

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