Laser-induced nanocrystalline silicon formation in a-SiO matrices

Nanocrystalline silicon formation by CW laser-irradiation of amorphous silicon–oxygen alloys of variable composition has been investigated as a function of both laser power density and alloy composition. Structural changes during the annealing treatment were monitored ‘in situ’ by micro Raman spectroscopy. Careful Raman lineshape analysis in the 450–550 cm−1 range allowed the evaluation of Si nanocrystal size distribution. It is shown that depending on the size of the nanocrystallites, irradiation can yield to a strong photoluminescence (PL) enhancement or quenching.