Wavelength dependence in photosynthesis of porous silicon dot

Porous silicon dot was fabricated by laser induced etching of single crystal silicon wafer immersed in hydrofluoric solution. The result shows that there is strong photo-chemical reaction on the laser irradiated silicon surface. Various incident wavelengths have been used to fabricate the porous silicon dots. It is found that there is a significant shift in photoluminescence peak when using infra-red light as etching wavelength. We proposed that there are two possible mechanisms responsible for the shift; one is electronic and the other is photo-chemical.