Size-controlled Si Nanocrystals

Abstract

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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)


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