|
In this paper, we investigate the effect of Ge nanocrystal size on
the Raman results. The Ge nanocrystal size distributions of samples rapid
thermally annealed at 800 and 1000 °C for 300 s were obtained from the TEM
pictures. We constructed the theoretical Raman spectrum based on the phonon
confinement model taking into account of the size distribution of the
nanocrystals. By taking into account of the Ge nanocrystal size distribution,
we found a good fit between the experimental and theoretical Raman results at
the lower wavenumber portion from the Raman peak for samples annealed at 800
and 1000 °C. Our model, however, is not able to account for the portion in the
Raman spectra above the Raman peak. We suggest that stress in the annealed
films maybe responsible for this discrepancy.
|