Size-controlled Si Nanocrystals


Basic Investigations:

M. Zacharias, J. Heitmann, and L.X. Yi



Preparation of size and density controlled Si nanocrystals:

  • growth of SiOx/SiO2 superlattices by reactive vapor deposition
  • creation of nanoclusters by phase separation of the SiO layers


Optical properties of Si nanocrystals

  • prove of the quantum confined origin of the PL signal
  • study of excitonic confinement and migration effects in the nanocrystals


Study of the crystallization process from point of theory

  • crystallization theory in the limit of ultra thin layer thickness
  • phase segregation of non stoichiometric oxides (SiOx)
  • Ostwald processes


Study of the phase separation and the crystallization process by experiments

  • influence of thermal annealing by furnace or rapid thermal annealing
  • X-ray diffraction
  • transmission electron microscopy including high resolution
  • Raman experiments


Doped nanophotonic structures

  • Er ion implantation of thin oxide layers containing Si nanocrystals for photonic applications
  • characterization of Förster transfer between Si nanocrystals and Er ions



Si nanocrystals are arranged in parallel monolayers embedded inside silicon oxide matrix. Size control for the crystals is realized by using a SiO2/SiO/SiO2 superlattice structure with the embedded SiO layer having the thickness of the desired Si nanocrystals and using a high-temperature annealing to form Si nanocrystals. L.X. Yi et al., Appl. Phys. Lett. 81 (2002) 4248




Heitmann, J. , F. Müller , L. X. Yi , M. Zacharias , D. Kovalev , and F. Eichhorn
Excitons in Si nanocrystals: Confinement and migration effects.
Physical Review B 69 (19) , 195309 (2004)

back  |  print  |  to top