Band structure of Si/Ge core-shell nanowires along the [110] direction modulated by external uniaxial strain

Xihong Peng, Fu Tang, Paul Logan

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

Strain modulated electronic properties of Si/Ge core-shell nanowires along the [110] direction were reported, on the basis of first principles density-functional theory calculations. In particular, the energy dispersion relationship of the conduction/valence band was explored in detail. At the Γ point, the energy levels of both bands are significantly altered by applied uniaxial strain, which results in an evident change of the band gap. In contrast, for the K vectors far away from Γ, the variation of the conduction/valence band with strain is much reduced. In addition, with a sufficient tensile strain (∼1%), the valence band edge shifts away from Γ, which indicates that the band gap of the Si/Ge core-shell nanowires experiences a transition from direct to indirect. Our studies further showed that effective masses of charge carriers can also be tuned using the external uniaxial strain. The effective mass of the hole increases dramatically with tensile strain, while strain shows a minimal effect on tuning the effective mass of the electron. Finally, the relation between strain and the conduction/valence band edge is discussed thoroughly in terms of site-projected wavefunction characters.

Original languageEnglish (US)
Article number115502
JournalJournal of Physics Condensed Matter
Volume23
Issue number11
DOIs
StatePublished - Mar 23 2011

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axial strain
Band structure
Nanowires
nanowires
Valence bands
Tensile strain
valence
conduction
Energy gap
Wave functions
Charge carriers
Electronic properties
Electron energy levels
Density functional theory
Direction compound
Tuning
charge carriers
energy levels
tuning
density functional theory

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)

Cite this

Band structure of Si/Ge core-shell nanowires along the [110] direction modulated by external uniaxial strain. / Peng, Xihong; Tang, Fu; Logan, Paul.

In: Journal of Physics Condensed Matter, Vol. 23, No. 11, 115502, 23.03.2011.

Research output: Contribution to journalArticle

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