In simulations we used the dielectric constants of Si3N4 and SRN bulk films (see Fig. 1 and
Fig. 2). The dielectric constants were found from the spectral ellipsometry measurements of
the Si3N4 and SRN films. The preparation parameters of these films are described in the
paper. The samples were annealed at 1100°C in N2 atmosphere for 1h. Cauchy model was
used to fit the data. The thicknesses of the reference Si3N4 and SRN films after annealing
were 56 and 66 nm respectively. Note that the annealed refractive indexes which are shown in
Figs. 1 and 2 are found to be slightly higher than the as-prepared.
The detailed scheme of the dipole planes location of Model A and Model B is shown in
Figure 3. In simulations we assumed that the optical constants of thin Si3N4 and SRN films
are equal those of the reference bulk Si3N4 and SRN films (Fig. 1 and Fig. 2).
FIG. 1.Optical constants of Si3N4 annealed bulk film used for the simulations: refractive index n and absorption
coefficient k versus wavelength measured by spectral ellipsometry.
FIG. 2. Optical constants of SRN annealed bulk film used for the simulations: refractive index n and absorption
coefficient k versus wavelength measured by spectral ellipsometry.
FIG. 3.A detailed scheme of TMM-simulations; Model A: dipole planes located in former SRN layers, Model B:
dipole planes located in Si3N4 matrix, i.e. in capping layer, 85% in former barrier layers, 15% in former SRN
layers. Number of bilayers is 20. In order to take into account the effect of the post annealing shrinkage of the
samples, in simulations all thicknesses were reduced by a factor of 0.2 in comparison to the thicknesses shown in
this figure on the right hand side. In spite of the fact that this reduction does not reflect properly the real postannealing change of layer thicknesses (see Table I in the manuscript), this approach enables us to describe
properly the experimental PL spectra.