Communication—effect of free-carrier absorption on an anodized silicon surface for producing dense and uniform nanocrystals

The present study disclosed that free-carrier absorption (FCA) activated by 1310-nm laser irradiation caused a distinct effect on the formation of nanocrystals in the porous layer of p⁺⁺ silicon with the anodization less than 10 minutes. Under ultraviolet excitation, the photoluminescence peak locations are quite different in the irradiated spot (∼535 nm) and in the normal porous silicon (∼640 nm). In the irradiated spot, the intensity of the photoluminescence is at least 10 times higher than that of the peripheral porous silicon layer. This shows that the FCA effect provides an alternative way to produce dense and uniform nanocrystals.