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Excitation spectrum of point defects in semiconductors studied by time-dependent density functional theory

Published online by Cambridge University Press:  24 January 2012

Adam Gali
Adam Gali*
Affiliation:
Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, H-1525; and Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, H-1111, Hungary
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

A common fingerprint of the electrically active point defects in semiconductors is the transition among their localized defect states upon excitation, which may result in characteristic absorption- or photoluminescence spectrum. Identification of such point defects by means of density functional theory (DFT) calculations with traditional (semi) local functionals suffers from two problems: the “band gap error” and the many-body nature of the electron-hole interaction of the excited state. We show that non local hybrid density functionals may effectively mimic the quasiparticle correction of the band edges and the defect levels within the band gap in group-IV semiconductors, thus they can effectively heal the “band gap error.” The electron-hole interaction can be calculated by time-dependent DFT (TD-DFT) method. Here, we apply TD-DFT on three topical examples: nitrogen-vacancy defect in diamond, silicon-vacancy and divacancy defects in silicon carbide that are candidates in effective development of solid-state quantum bits.

Keywords

DefectsNanostructurePhotoemission
Type
Invited Feature Paper
Information
Journal of Materials Research , Volume 27 , Issue 6 , 28 March 2012 , pp. 897 - 909
Copyright
Copyright © Materials Research Society 2012

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References

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