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

Conclusion and future perspectives
Fullled thesis objectives
tel-00916300, version 1 - 10 Dec 2013
A systematic study on the growth techniques and material properties was made
towards fullling the four major objectives of this thesis. Therefore, the results of
this thesis are also summarized into four parts as follows:
1. Material growth technique
The rst major objective was to increase the density of Si-np in SRSO layers. This
requires a higher incorporation of Si inside the SRSO layer during the sputtering
process. In order to achieve this, two strategies were employed:
Strategy 1: Varying the deposition parameters such as deposition temperature,
hydrogen rate and power applied on the Si cathode in the already established reactive
sputtering and co-sputtering approaches.
Outcome: A temperature dependent growth mechanism was proposed, and it
was shown that T d = 500°C favours the agglomeration of Si even during deposition,
which is conrmed by characterization studies performed on those layers. This
agglomeration of Si will serve as seeds for Si-np formation on further annealing.
Strategy 2: Combining the advantages of reactive sputtering and co-sputtering
approaches in favouring Si incorporation, and developing a new approach called as
the Reactive co-sputtering.
Outcome: High refractive indices were obtained, and the formation of Si-np in
SRSO monolayers as well as SRSO sublayers in a ML conguration were witnesssed
even in the as-grown state. It was seen that upon annealing, the Si-np density in
SRSO reaches about 3 x 10 19 np/cm 3 in SRSO/SiO 2 MLs and about 10 20 np/cm 3
in SRSO/SRSN MLs thus fullling the rst objective of this thesis.
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