  Visible luminescence is observed from the composite of SiO2 with embedded
silicon nanocrystallites produced by femtosecond laser irradiation of
hydrogenated amorphous silicon (a-Si:H) film in air. The photoluminescence
originates from the defect states at the interface between silicon crystallites
and SiO2 matrix. The method could be used for fabrication of luminescent layers
to increase energy conversion of a-Si:H solar cells.
