Fabrication of luminescent a-Si:SiO2 structures by direct irradiation of high power laser on silicon surface

In this paper, the structural and compositional modification of polished silicon (Si) wafers by irradiation of second harmonic of Q switched high power Nd: YAG laser in air is reported. The surface morphology, recorded by scanning electron microscope (SEM), shows micro cluster formation. Raman spectra reveal the presence of amorphous silicon embedded in silicon dioxide (SiO2) matrix in these structures which is further confirmed by energy dispersive X-ray (EDX) and Fourier transform infrared (FTIR) spectroscopic studies. These nanostructures of amorphous Si embedded in SiO2 matrix (a-Si:SiO2) showed luminescence in far red region. The effect of laser fluence on the photoluminescence properties and its possible origin were discussed.