First-principles calculations for defects and impurities: Applications to III-nitrides
Top Cited Papers
- 15 April 2004
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 95 (8), 3851-3879
- https://doi.org/10.1063/1.1682673
Abstract
First-principles calculations have evolved from mere aids in explaining and supporting experiments to powerful tools for predicting new materials and their properties. In the first part of this review we describe the state-of-the-art computational methodology for calculating the structure and energetics of point defects and impurities in semiconductors. We will pay particular attention to computational aspects which are unique to defects or impurities, such as how to deal with charge states and how to describe and interpret transition levels. In the second part of the review we will illustrate these capabilities with examples for defects and impurities in nitride semiconductors.Point defects have traditionally been considered to play a major role in wide-band-gapsemiconductors, and first-principles calculations have been particularly helpful in elucidating the issues. Specifically, calculations have shown that the unintentional n -type conductivity that has often been observed in as-grown GaN cannot be attributed to nitrogen vacancies, but is due to unintentional incorporation of donor impurities. Native point defects may play a role in compensation and in phenomena such as the yellow luminescence, which can be attributed to gallium vacancies. In the section on impurities, specific attention will be focused on dopants. Oxygen, which is commonly present as a contaminant, is a shallow donor in GaN but becomes a deep level in AlGaN due to a DX transition. Magnesium is almost universally used as the p -type dopant, but hole concentrations are still limited. Reasons for this behavior are discussed, and alternative acceptors are examined. Hydrogen plays an important role in p -type GaN, and the mechanisms that underlie its behavior are explained. Incorporating hydrogen along with acceptors is an example of codoping; a critical discussion of codoping is presented. Most of the information available to date for defects and impurities in nitrides has been generated for GaN, but we will also discuss AlN and InN where appropriate. We conclude by summarizing the main points and looking towards the future.Keywords
This publication has 150 references indexed in Scilit:
- Thermal annealing effect on nitrogen vacancy in proton-irradiated AlxGa1−xNApplied Physics Letters, 2002
- Detection of Interstitial Ga in GaNPhysical Review Letters, 2000
- Local vibrational modes as a probe of activation process in p-type GaNApplied Physics Letters, 1999
- Gallium vacancies and the growth stoichiometry of GaN studied by positron annihilation spectroscopyApplied Physics Letters, 1998
- Density-functional theory calculations for poly-atomic systems: electronic structure, static and elastic properties and ab initio molecular dynamicsComputer Physics Communications, 1997
- Optical properties of doped GaN grown by a modified molecular beam epitaxial (MBE) process on GaAs substratesJournal of Crystal Growth, 1996
- Metastability and persistent photoconductivity in Mg-doped p-type GaNApplied Physics Letters, 1996
- On p-type doping in GaN—acceptor binding energiesApplied Physics Letters, 1995
- First-principles calculations of hyperfine parametersPhysical Review B, 1993
- Pseudopotential methods in condensed matter applicationsComputer Physics Reports, 1989