Abstract: Certain low-dimensional nanostructures can be formed by laser irradiation on pure silicon samples and on the SiGe alloy samples.These low-dimensional nanostructures are generated by the interaction between semiconductors and the plasma produced with laser irradiation.We studied the photoluminescence (PL) of the hole-net structure of silicon and the porous structure of SiGe where the PL intensity at 706nm and at 725nm wavelength increases significantly.It is proved that surface oxidation of these structures occurs.The effect of intensity-enhancement of the PL peaks cannot be explained by quantum confinement alone.We propose a mechanism for increasing PL emission in the above structures,in which the trap states of the interfaces between SiO2 and nanocrystal play an important role.

Key words: low-dimensional nanostructures, plasma wave, photoluminescence