Synthesis and white photoluminescence of porous polysilicon

Abstract

Porous polysilicon is fabricated through hydrothermally etching polysilicon in the solution of hydrofluoric acid containing ferric nitrate, which is characterized by the pores with ~40nm and silicon nanocrystals (nc-Si) with an average size of ~4.1nm. Compared with the polysilicon, the reflectance of porous polysilicon is rather low. Using the Kubelka-Munk method, the band gap with ~3.35eV can be calculated. Under the excitation of 270nm, the white photoluminescence, which chromaticity coordinate, correlative color temperature and color rendering index are (0.36, 0.32), ~4185K and ~83.4, respectively, can be observed. Utilizing Gauss-Newton fitting method, white light can be decomposed into ultraviolet emission, blue emission and orange-red emission. Three peaks are attributed to the band gap emission of nc-Si, the luminescence centers formed in the silicon oxide layer and in the surface of nc-Si or in the silicon suboxidation layer encapsulating nc-Si, respectively. It is indicated that porous polysilicon might be a potential material in the white light emission field.