TEM investigation of Si nanocrystals formed by ion implantation
Abstract
The small size of silicon nanocrystals (Si-nc) is responsible for the photoluminescence (PL) of this material. Transmission electron microscopy has been used to study Si-nc formed by ion implantation into an amorphous silicon oxide (SiO_2) film. Si-ions were implanted at the energy of 100 keV into the SiO_2 film at different implantation doses (2.10^16;8.10^16;3.10^17 Si^+/cm^2). The material was then submitted to an annealing at 1100 ^oC for 1 or 4 h in an N_2 atmosphere and to a passivation of 500 ^oC for 1 h in a forming gas (5% H_2 and 95% N_2). High resolution TEM micrographs were used to determine the shapes of the Si-nc and the inter planar distances. This latter is in accord with the Si structure. The size (2-5 nm) of Si-nc were measured on dark field TEM micrographs and found to vary according to different doses. The quantum confinement model can give the PL spectrum associated to a mean theoretical grain size and a width of the nanograin size distribution. This model contains a constant C whose values are found in the literature. With the mean grain size observed by TEM and the actual size distribution an experimental value of C was obtained.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MAR.K1045L