Films minces à base de Si nanostructuré pour des cellules ...

In the case of our multilayers, there is a periodical distribution of emitters since
Si-np are restricted only to SRSO sublayers. Figure 5.8 illustrates the case of MLs
comprised of alternative emitting sublayers and non-emitting sublayers.
tel-00916300, version 1 - 10 Dec 2013
Figure 5.8: An illustration of the pump prole variation in a thin lm of thickness d(nm)
with distribution of emitters in multilayer congurations.
More emitters would be excited in those sublayers which experience a pump
maxima. Depending upon the sublayer thicknesses, the number of emitters that are
excited varies, as well as the emission intensity. This implies that the population of
the excited state of emitters follows the shape of the incident pump prole, which
will be discussed in the next sections.
As seen from the discussions in this section, modeling reveals that the incident
laser intensity in the PL experiment depends upon various parameters such as the
angle of incidence, thickness, refractive index, type of congurations etc. Since the
pump prole contributes to the emission intensity, these results indicate that the
variations in PL intensity cannot be directly linked to the emitter density in the
thin lm.
5.3 Emission modeling
Similar to the pump prole, the emission from thin lm is also inuenced by various
components such as the thickness of the lm, the distribution of emitters, their
population density in the ground and excited states, lifetime of carriers, absorpion
and emission cross sections. Experimental data and literature values are used to
simulate PL curves in order to see the inuence of our material parameters on
emission intensity.
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