Silicon Carbide Nanotubes As Potential Gas Sensors for CO and HCN Detection

Semiconducting carbon nanotubes (CNTs) have demonstrated extreme sensitivity to molecules such as NH3, NO, NO2, ans so forth. Yet, intrinsic CNTs cannot be used to detect some highly toxic molecules such as CO and HCN. In this article, we examine the possibility of silicon carbide nanotubes (SiCNTs) as a potential gas sensor for CO and HCN detection by first-principles calculations based on density functional theory (DFT). It is found that CO and HCN molecules can be absorbed to Si atoms on the wall of SiCNTs with binding energies as high as 0.70 eV and can attract finite charge from SiCNTs. By comparison to oxygen absorption on CNTs, we infer that molecular CO and HCN absorbed on SiCNTs can induce significant change in the conductivity of SiCNTs. In view of the high portion of the reactive area, SiCNTs can be potential efficient gas sensors for CO and HCN detection.