The controllable growth of superhydrophobic SiC nanowires by tailoring the cooling rate

Abstract

In the present work, we report the controlled growth of SiC nanowires on a silicon substrate by tailoring the cooling rate of a catalyst-assisted method. SEM analysis indicates that SiC nanowires with different morphologies are formed by varying the cooling rate. The growth of SiC nanowires with small diameters was achieved by increasing the cooling rate. When a fast cooling rate of 16.7 °C min⁻¹ was applied, each SiC nanowire possessed a uniform and smooth surface without impurities. In comparison, numerous disordered SiC nanowires with coiled morphologies were obtained at a slow cooling rate of 2.08 °C min⁻¹. The nanowires obtained at the fast cooling rate were nearly 10 times longer than those obtained at the slow cooling rate. The SiC nanowire film obtained at the fast cooling rate exhibited excellent superhydrophobicity, with a water contact angle of up to 150° without any surface functionalization. A sharp ultraviolet peak at 360 nm was observed in the spectra of as-grown nanowires at fast cooling rates. In addition, the emission intensity of the ultraviolet peak decreased with the decreasing cooling rates. The current work is anticipated to provide a novel and general strategy for the growth of SiC nanowires with well-controlled morphologies.