Visible luminescence from hydrogenated amorphous silicon modified by femtosecond laser radiation

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

Femtosecond laser induced crystallization of hydrogenated amorphous silicon for photovoltaic applications

Femtosecond laser assisted crystallization is used to produce nanocrystalline silicon from hydrogenated amorphous silicon. Changes in structural, optical, electrical and photoelectric properties of laser modified amorphous silicon were investigated. Laser treated films were characterized using atomic force microscopy, Raman spectroscopy, constant photocurrent method and current measurements. Crystalline volume fraction as well as conductivity of laser irradiated films increased with the applied laser fluence, while hydrogen concentration in the films was found to decrease with the fluence. Spectral dependences of absorption coefficient, measured by constant photocurrent method, are discussed in terms of hydrogen out-effusion and additional defect state formation in silicon films during the laser treatment

Visible luminescence from hydrogenated amorphous silicon modified by femtosecond laser radiation

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

Structural and electrophysical properties of femtosecond laser exposed hydrogenated amorphous silicon films

This paper studies the effect of femtosecond laser treatment in air of hydrogenated amorphous silicon thin films (a-Si:H) on their structural, electrical and photoelectric properties. The possibility of laser-induced crystallization of a-Si:H films with controlled crystalline volume fraction was shown. A sufficient increase of dark conductivity was observed for laser treated a-Si:H films which crystallinity exceeds 7%. Such increase was attributed to change in conductivity mechanism. However, spectral dependences of absorption coefficient did not show any qualitative changes with the laser fluence increase. It was found that spallation and oxidation of the film took place when laser fluence became reasonably high