In situ photoluminescence spectral study of porous Si in HF aqueous solution

Time-dependent change in the visible luminescence of porous Si immersed in HF aqueous solution was measured in a short acquisition time (5 s) with a charge coupled device detector. Under Ar+ laser light (514.5 nm) irradiation, the photoluminescence band of the porous Si shifted to shorter wavelength accompanying a reduction of the peak intensity. The result suggests that the size of the Si nanostructure is closely related to the gap energy of the porous Si.