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

(a) Inuence of various values for cross-sections and
width on the PL spectra.
(b) PL spectra from trial 3.
tel-00916300, version 1 - 10 Dec 2013
Figure 5.22: Theoretically modeled spectra considering double kind of emitters. The
inset of sub-gure (b) shows the lorentzian t performed on the PL spectra from trial 3.
The details of all the trials are given in Appendix II.
the PL band. Therefore, the tting results on gure 5.22b conrm that, it is the
existence of two kinds of emitters that lead to emission in SRSO/SiO 2 ML in the
range of investigation.
5.5.2 Inuence of t SiO2 on the PL intensity
The role of SiO 2 as a barrier was explained in chapter 3, using which the PL spectra
were also interpreted. Since it is shown in this chapter that the pump prole varies
along the depth of penetration, it is clear that other factors also contribute to the
emission intensity variation.
Figures 5.23(a-e) show the pump prole and the distribution of emitters in the
excited state N 3 (x), with varying t SiO2 . From N 3 (x), we can identify the SiO 2
sublayer positions where N 3 (x) = 0. The ve cases presented in this gure refer to
SRSO/SiO 2 MLs with a constant density of emitters restricted within 3 nm SRSO
sublayers. With increasing total thickness as a consequence of increasing t SiO2 ,
the pump prole also evolves from almost two maxima to ve maxima when t SiO2
changes from 1.5 nm to 10 nm. It can also be seen from these gures that the
distribution of emitters varies between maxima to minima in accordance with the
pump prole.
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