Novel synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotubes: The effect of the heating temperature

Abstract

Silicon carbide nanomaterials, especially silicon carbide nanotubes (SiCNTs), are known as excellent materials for high-power and high-temperature harsh environment electronics applications because of the unique properties of SiCNTs, such as a high thermal stability, good chemical inertness and excellent electronic properties. In this article, we presented a novel synthesis of SiCNTs by microwave heating a blend of silicon dioxide (SiO2) and multi-walled carbon nanotubes (MWCNTs) at a ratio of 1:3 at temperatures of 1350°C, 1400°C and 1450°C. The effects of different heating temperatures on the synthesis of SiCNTs were studied. X-ray diffraction revealed the presence of single phase β-SiC for syntheses conducted at 1400°C and 1450°C. Meanwhile, field-emission scanning electron microscopy images showed that no residual silicon dioxide or MWCNTs was observed with syntheses conducted at 1400°C and 1450°C. High-magnification transmission electron microscopy revealed that the tubular structure of the MWCNTs was preserved and that SiCNTs had a lattice fringe spacing of 0.261nm corresponding to the (111) plane of β-SiC. Photoluminescence spectroscopy showed the presence of a β-SiC peak at a wavelength of 465nm, and the band gap energy of SiCNTs was 2.67eV. Fourier transform infrared spectroscopy analysis revealed that the absorption band of the Si–C bond was detected at 803cm−1. The purity of SiCNTs synthesized at 1400°C and 1450°C is high, as indicated by the low weight loss in thermo-gravimetric analysis.