Blue-light emission from porous silicon induced by laser irradiation

Porous silicon coated with silica gel emitted light with higher energy after it had been irradiated by a Nd:YAG laser. SEM and XRD measurements demonstrate no crystal-to-amorphous transformation under the irradiation, which is presumably because of good protection of the material by silica coat. FTIR results show that the blue-light emission obtained is due to the formation of Si–C and Si–O–C surface bonds under the laser treatment.