Structural transition in nanosized silicon clusters

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Original languageEnglish
Article number245417
Journal / PublicationPhysical Review B - Condensed Matter and Materials Physics
Volume65
Issue number24
Online published13 Jun 2002
Publication statusPublished - 15 Jun 2002

Abstract

The structural transition to bulk diamond structure in nanosized silicon clusters has been studied by tight-binding calculations. For intermediate-size clusters (<200 atoms), the energetically favorable structures obtained consist of small subunits like Si10 and Si12, qualitatively consistent with the experimental fragmentation behavior of these clusters. For spherical silicon nanocrystals, the surface atoms reconstruct to minimize the number of dangling bonds, forming a continuous surface. The large curvature of the continuous surface causes lattice contraction in the nanocrystals. Present calculations predict the lattice contraction versus the particle radius as Δa≈0.4/R, with Δa and R in Å. By comparing cohesive energies of the two sorts of structures, the structural transition is estimated to occur in the range of 300–500 atoms, or about 2.3–2.7 nm in diameter.