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

tel-00916300, version 1 - 10 Dec 2013
Figure 2.18: Step 3 and Step 4 of ellipsometry modelling.
2.2.8 Photoluminescence Spectroscopy
Principle
Photoluminescence (PL) spectroscopy is a non-destructive method that gives information
on the electronic structure of materials. When a sample absorbs the
incident photons, it gains excess energy and the electrons in the material get excited
to permissible energy states (photo-excitation). When these electrons return to their
ground states, the excess energy is released with (a radiative process) or without the
emission of light (non-radiative process). The light emitted in a radiative process is
called photoluminescence. Figure 2.19 illustrates the processes explained above for
an incident light at 488 nm and emission between 700-900 nm range. The radiative
transitions in semiconductors may also involve localized levels and defect states in
addition to the bandgap transitions. In this case, the PL analysis also leads to the
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