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

Figure 1.1: World energy consumption-2007 Statistics [Internet 03].
tel-00916300, version 1 - 10 Dec 2013
ductors to convert light into electric energy. Solar PV can be eectively used to
power isolated homes in remote places.
The sustainability and availability of the solar energy serves as a motivation to
achieve cost-eective PV devices with high eciency, by developing novel materials.
1.2 Solar Photovoltaics
1.2.1 A brief history of PV cells
The solar photovoltaic approach generates power using solar panels, which are
made up of a large number of solar cells. It works on the principle discovered by
Edmond Becquerel in 1839 known as the photovoltaic eect, which is the production
of current in a material on illumination. A century later, Russel Ohl discovered the
presence of a p-n junction in Silicon, by observing that one area of the material offered
more resistance to current ow than the other, when heated or illuminated. He
reasoned this junction formation to be a contribution from segregation of impurity
in recrystallized silicon (Si) melts during the growth of monocrystalline Si rods. This
discovery of p-n junction resulted in the rst PV devices in 1941 [Ohl 41a, Ohl 41b].
In 1952, conversion eciency of about 1% was achieved by controlling the location of
junction formation, which was a major problem in the earlier devices [Kingsbury 52].
In 1954, the rst modern solar cell developed at the Bell laboratories using the silicon
p-n junction, increased the eciency to 6% which is the rst milestone in the
PV research industry [Chapin 54]. The wide usage of PV cells for space applications
resulted in modications of the device structures by placing contact grids on the top
surface and this resulted in a further increase of eciency to 14% [Mandelkorn 62].
Eversince, a lot of materials have been investigated for PV applications and presently
6