First-principles study on the origin of band-gap reduction in Si-lattice matched Si1-x-yGexCy

M. Ohfuti, Yuji Awano, N. Yokoyama

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The electronic structure of a Si-lattice matched Si1-x-yGexCy crystal, with x=37.5% and y=3.1%, is studied using a first-principles energy-band calculation. The state at the bottom of the conduction bands in the Si1-x-yGexCy is found to be similar to that in the Si1-xGex crystal with the same x. The band gap of the Si1-x-yGexCy crystal is smaller than the unstrained Si1-xGex crystal and agrees with that of the Si1-xGex virtually lattice matched to the Si1-x-yGexCy crystal. The band gap of a Si1-yCy crystal with the same y is larger than or equal to that of the Si crystal. It can be concluded that the band-gap reduction in the Si1-x-yGexCy crystal is attributed to a lattice shrinkage effect resulting from the introduction of the small C and does not originate from the chemical effect by the introduced C. The calculated coefficient of the band-gap reduction in the Si1-x-yGexCy alloy agrees well with that reported for y up to 1% in an experiment, which suggests that the band-gap reduction for the low-C concentrations observed in the experiment may be explained by the origin found numerically for y=3.1%.

Original languageEnglish
Pages (from-to)15515-15518
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume60
Issue number23
Publication statusPublished - 1999 Dec 15
Externally publishedYes

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Energy gap
Crystals
crystals
Crystal lattices
chemical effects
Conduction bands
shrinkage
Band structure
Electronic structure
energy bands
conduction bands
Experiments
electronic structure
coefficients

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

First-principles study on the origin of band-gap reduction in Si-lattice matched Si1-x-yGexCy. / Ohfuti, M.; Awano, Yuji; Yokoyama, N.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 60, No. 23, 15.12.1999, p. 15515-15518.

Research output: Contribution to journalArticle

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