Journal of Mathematical Chemistry

, Volume 46, Issue 3, pp 942–951 | Cite as

Mixed silicon–germanium nanocrystals: a detailed study of SixGe47−x:H

  • A. D. Zdetsis
  • C. S. Garoufalis
  • E. N. Koukaras
Original Paper

Abstract

Mixed SiGe:H nanocrystals have been studied within the framework of Density Functional Theory. (DFT) using the hybrid non-local exchange-correlation functional of Becke, Lee, Parr and Yang (B3LYP). In addition to ground-state DFT/B3LYP calculations, excited-state calculations for the determination of the optical absorption spectrum have been performed employing the time-dependent density functional theory (TDDFT). In order to fully investigate the substitution of Si by Ge, on structural, cohesive, electronic and optical properties, we have used the SixGe47−x:H nanocrystal, as a representative medium size nanosystem. Our results show that the optical gap depends not only on the relative concentrations of silicon, germanium and hydrogen, but also on the relative position of the silicon and germanium shells relative to the surface of the nanocrystal. This is also true for the structural, cohesive and electronic properties. This dependence allows for the possibility of electronic and optical gap engineering.

Keywords

Nanocrystals Nanoparticles Optical gap Density functional theory 

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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • A. D. Zdetsis
    • 1
  • C. S. Garoufalis
    • 1
  • E. N. Koukaras
    • 1
  1. 1.Department of PhysicsUniversity of PatrasPatrasGreece

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