Neutral Vacancies in Group-IV Semiconductors

✍ Scribed by A. Zywietz; J. Furthmüller; F. Bechstedt

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 347 KB
• Volume: 210
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/(sici)1521-3951(199811)210:1<13::aid-pssb13>3.0.co;2-p

✦ Synopsis

Ab initio plane-wave-supercell calculations are performed for the neutral monovacancies in silicon, silicon carbide and diamond using ultrasoft non-normconserving Vanderbilt pseudopotentials. We study the structure, the energetics and the single-particle energy spectrum. The local symmetry, the atomic displacements, and the formation energies are found to be sensitive with respect to the numerical details. The convergence of the calculations with the supercell size is demonstrated. We find a tendency for the stabilization of the tetragonal D 2d symmetry for the vacancy in Si and the C vacancy in SiC, whereas the Si vacancy in SiC and the vacancy in diamond nearly conserve the T d symmetry. The structural changes are related to the electronic defect states. Defect levels are derived for the four vacancies under consideration.