Journal of Mathematical Chemistry

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

Mixed silicon–germanium nanocrystals: a detailed study of Si x Ge47−x :H

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


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 Si x Ge47−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.


Nanocrystals Nanoparticles Optical gap Density functional theory 


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  1. 1.
    Canham L.T.: Appl. Phys. Lett. 57, 1046 (1990)CrossRefGoogle Scholar
  2. 2.
    Wilcoxon J.P., Provencio P.P., Samara G.A.: Phys. Rev. B 64, 035417 (2001)CrossRefGoogle Scholar
  3. 3.
    Wolkin M.V., Jorne J., Fauchet P.M., Allan G., Delerue C.: Phys. Rev. Lett. 82, 197 (1999)CrossRefGoogle Scholar
  4. 4.
    Reboredo F.A., Franceschetti A., Zunger A.: Phys. Rev. B 61, 13073 (2000)CrossRefGoogle Scholar
  5. 5.
    Schuppler S.L. et al.: Phys. Rev. Lett. 72, 2648 (1994)CrossRefGoogle Scholar
  6. 6.
    Schuppler S.L. et al.: Phys. Rev. B 52, 4910 (1995)CrossRefGoogle Scholar
  7. 7.
    Rohlfing M., Louie S.G.: Phys. Rev. Lett. 80, 3320 (1998)CrossRefGoogle Scholar
  8. 8.
    Öğüt S., Chelikowsky J., Louie S.G.: Phys. Rev. Lett. 79, 1770 (1997)CrossRefGoogle Scholar
  9. 9.
    Öğüt S., Chelikowsky J., Louie S.G.: Phys. Rev. Lett. 80, 3162 (1998)CrossRefGoogle Scholar
  10. 10.
    Brus L.E., Szajowski P.F., Wilson W.L., Harris T.D., Schuppler S., Citrin P.H.: J. Am. Chem. Soc. 117, 2915 (1995)CrossRefGoogle Scholar
  11. 11.
    Kim K.: Phys. Rev. B 57, 13072 (1998)CrossRefGoogle Scholar
  12. 12.
    Furukawa S., Miyasato T.: Phys. Rev. B 38, 5726 (1988)CrossRefGoogle Scholar
  13. 13.
    Kanemitsou Y.: Phys. Rev. B 49, 16845 (1994)CrossRefGoogle Scholar
  14. 14.
    Vasiliev I., Chelikowsky J.R., Martin R.M.: Phys. Rev. B 65, 121302-1 (2002)Google Scholar
  15. 15.
    Garoufalis C.S., Zdetsis A.D., Grimme S.: Phys. Rev. Lett. 87, 276402 (2001)CrossRefGoogle Scholar
  16. 16.
    A.D. Zdetsis, C.S. Garoufalis, S. Grimme, Proceedings of NATO Advanced Research Workshop on “Quantum Dots: Fundamentals, Applications, and Frontiers” Crete, Greece (Kluwer/Springer, Dordrecht/New York, 2005), pp. 317–332Google Scholar
  17. 17.
    Zdetsis A.D.: Rev. Adv. Mater. Sci. 11, 56–78 (2006)Google Scholar
  18. 18.
    Weissker H.Ch., Furthmuller J., Bechstedt F.: Phys. Rev. B 65, 155328 (2002)CrossRefGoogle Scholar
  19. 19.
    Garoufalis C.S., Zdetsis A.D.: J. Phys. Conf. Ser. 10, 69 (2005)CrossRefGoogle Scholar
  20. 20.
    Zdetsis A.D., Garoufalis C.S., Skaperda M.S., Koukaras E.N.: J. Phys. Conf. Ser. 10, 97 (2005)CrossRefGoogle Scholar
  21. 21.
    Yu M., Jayanthi C.S., Drabold D.A., Wu S.Y.: Phys. Rev. B 68, 035404 (2003)CrossRefGoogle Scholar
  22. 22.
    M.E. Casida, in Recent Advances in Density Functional Methods, vol. 1, ed. by D.P. Chong (World Scientific, Singapore, 1995)Google Scholar
  23. 23.
    Stephens P.J., Devlin F.J., Chabalowski C.F., Frisch M.J.: J. Phys. Chem. 98, 11623 (1994)CrossRefGoogle Scholar
  24. 24.
    Tarus J., Tantarimaki M., Nordlund K.: Nucl. Instr. Meth. B 228, 51–56 (2005)CrossRefGoogle Scholar
  25. 25.
    TURBOMOLE (Version 5.6), Universitat Karlsruhe (2002)Google Scholar
  26. 26.
    Schäfer A., Horn H., Ahlrichs R.: J. Chem. Phys. 97, 2571 (1992)CrossRefGoogle Scholar

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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