Silicon Carbide Nanotubes Serving as a Highly Sensitive Gas Chemical Sensor for Formaldehyde

In order to search for a novel sensor to detect formaldehyde (HCOH), the interaction between HCOH and infinitely long zigzag single-walled silicon carbide nanotubes (SiCNTs) is investigated using density functional theory (DFT). Compared with the weak adsorption on carbon nanotubes, HCOH molecule tends to be chemisorbed to the Si–C bond of SiCNT with appreciable adsorption energy. The study of a second HCOH adsorption on SiCNT further confirms that the polarized Si–C pair is highly sensitive to the HCOH molecule. With the increase of the coverage of the adsorbed HCOH, the band gap of SiCNT is gradually decreased, thus leading to an enhancement of the conductivity property of SiCNT. It is expected that SiCNT could be a promising gas sensor for detecting the HCOH molecule.