An extended 'quantum confinement' theory: Surface-coordination imperfection modifies the entire band structure of a nanosolid

Chang Q. Sun, T. P. Chen, B. K. Tay, S. Li, Y. B. Zhang, Haitao Huang, L. K. Pan, Shu Ping Lau, X. W. Sun

Research output: Journal article publicationJournal articleAcademic researchpeer-review

75 Citations (Scopus)

Abstract

With the miniaturization of a solid, quantum and interface effects become increasingly-important. As a result, the band structure of a nanometric semiconductor changes: the band gap expands, the core level shifts, the bandwidth revises, and the sublevel separation within a band increases. Unfortunately, such a thorough change goes beyond the scope of currently available models such as the 'quantum confinement' theory. A consistent understanding of the factors dominating the band-structure change is highly desirable. Here we present a new approach for the size-induced unusual change by adding the effect of surface-coordination deficiency-induced bond contraction to the convention of an extended solid of which the Hamiltonian contains the intraatomic trapping interaction and the interatomic binding interaction. Agreement between modelling predictions and the observed size dependency in the photoluminescence of Si oxides and some nanometric III-V and II-VI semiconductors, and in the core-level shift of Cu-O nanosolids has been reached. Results indicate that the spontaneous contraction of chemical bonds at a surface and the rise in the surface-to-volume ratio with reducing particle size are responsible for the unusual change of the band structure of a nanosolid.
Original languageEnglish
Pages (from-to)3470-3479
Number of pages10
JournalJournal of Physics D: Applied Physics
Volume34
Issue number24
DOIs
Publication statusPublished - 21 Dec 2001
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

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