Porous silicon with double band photoluminescence fabricated by chemical-assisted picosecond laser irradiation

The fabrication of porous silicon with double band photoluminescence (PL) by chemical-assisted 1064 nm picosecond (ps) laser irradiation of polysilicon is presented. The hybrid method includes controlling of the laser scanning interval, number of scans to form dense micropores, and subsequently, short-time acid corrosion to form fine nanostructure. Along with the stable red PL visible to the naked eye, a new violet PL band at 432 nm existed in the fabricated samples. The double band photoluminescence was mainly attributed to the prepared micro/nano hierarchical structure. Moreover, dangling bond defects formed by high-energy photon impinging acted as the catalyzer in the subsequent acid corrosion resulted in good passivation of the nanostructure with the formation of Si-H and Si-O bond, which also contributed to the stable photoluminescence. The maximum surface porosity of the samples was concluded to be 90.48% which also bring good hydrophobicity for the prepared samples.