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

function of wavelength consists of the real part n and imaginary part k, known as
the extinction coecient. This is represented by,
Complex refractive index ñ = n(λ) − ik(λ) Eqn (5.14)
Figure 5.2 shows the shapes of simulated n(λ) and k(λ) by using the parameters
from our ellipsometry results on the corresponding thin lm, as the input.
tel-00916300, version 1 - 10 Dec 2013
Figure 5.2: The variation of complex refractive index (ñ = n(λ) − ik(λ)) of a thin lm,
as a function of wavelength.
The pump wavelength was xed at 488 nm in all the simulations, relating to the
Ar laser used in the PL experimental set-up.
(a) Inuence of Angle of incidence
The simulations consist of focussing
the pump on a 500 nm thin lm
with complex refractive index described
in gure 5.2. The pump pro-
le is investigated as a function of
depth (x) from the lm surface, for
two angles of incidence: normal incidence
and 45° incidence (Fig. 5.3).
This gure clearly indicates that
the incident pump intensity oscillates
between maxima and minima
along the depth (x). As a consequence,
even if the emitters are
homogeneously distributed within a
thin lm, they are subjected to a variable pump prole.
Figure 5.3: Pump intensity prole with regard
to its angle of incidence on the thin lm.
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