Fabrication of nanostructured silicon carbide from rice husks and its photoluminescence properties

Abstract

Nanostructured silicon carbide (SiC) particles and whiskers have been fabricated by pyrolysis of rice husks (RHs) in argon atmosphere. The results revealed that a complete carbothermal reduction of silica was achieved at 1600°C for 2 h and the final product was β-SiC. The β-SiC obtained on the bodies of pyrolyzed rice husks (PRHs) was mainly particles having diameters of 100–200 nm and the wool-like product formed on the inner walls of the graphite crucible was β-SiC whiskers with diameter of around 170 nm and tens of micrometers in length. Compared to bulk β-SiC, down-shifts and asymmetric broadening were observed on both transverse optical (TO) and longitudinal optical (LO) phonon peak in Raman scattering spectra of the nanostructured SiC. The photoluminescence (PL) spectra revealed that the nanostructured β-SiC, especially the β-SiC whiskers, showed excellent blue light emission property. The PL emission peak was considerable blue-shifted relative to that for the bulk β-SiC.