Controllable growth of high-density tapered N-doped SiC nanowires arrays

Abstract

Tapered nitrogen-doped SiC nanowires (N-doped SiCNWs) arrays were vertically grown on the carbon cloth utilizing Si, SiO2, C, and dicyandiamide powders as raw materials via a simple Fe(NO3)3 assisted chemical vapor deposition process. High-density tapered N-doped SiCNWs possessed homogeneous morphology. The diameter of the synthesized nanowire increased from ∼120 nm at the tail to ∼1.30 μm at the tip, while the length could be up to tens of micrometers. Moreover, the as-prepared N-doped SiCNWs were examined to be 2H/3C–SiC mixed crystals. The appearance of 2H crystal might be responsible for the high density defects in 3C–SiC. And since the interesting tapered shape was significantly affected by the catalyst droplet, the growth of N-doped SiCNWs may be governed by Fe-assisted VLS mechanism. In addition, the main emission peak of PL spectrum of N-doped SiCNWs was located at 474 nm, exhibiting a certain blue shift, which was mainly attributed to the special tapered shape, defects, 2H/3C–SiC heterostructure and the quantum confinement effect of the N-doped SiCNWs.