The origin of the photoluminescence (PL) shifts in Porous Silicon
(PS) is discussed according to a quantum confinement – based model, in
which we modelize the PS layer as a mixture of quantum dots and wires. It
was shown that a PL blueshift or redshift may occur during laser irradiation
of PS, depending on preparation conditions. No PL shift was observed for
some PS samples, even after a long ageing in air, due to the presence of an
amorphous silicon phase detected from Raman spectroscopy measurements. It
was found that the presence of the amorphous phase plays an important role
in the PL behaviour of oxidised PS.