Capacitive humidity sensing properties of SiC nanowires grown on silicon nanoporous pillar array

A large quantity of entangled SiC nanowires (nw-SiC) with an average diameter of ∼15 nm were grown on a silicon nanoporous pillar array (Si-NPA) by a catalyst-assisted chemical vapor deposition method. The room-temperature capacitive humidity sensing properties of nw-SiC/Si-NPA were studied by evaporating coplanar interdigital silver electrodes onto its surface. With the relative humidity (RH) changing from 11% to 95%, a capacitance increment over 960% was achieved at the measuring frequency of 100 Hz. The response and recovery times were measured to be ∼105 and 85 s, respectively, with a maximum humidity hysteresis of 4.5% at 75% RH. The humidity sensor was also proved to be with high measurement reproducibility and long-term stability. Our results indicate that one-dimensional SiC materials might be competitive as a novel sensing material for fabricating humidity sensors with high performances.