g-SiC and g-SiC2 siligraphenes as two multifunctional H2S sensing materials

The main purpose of this article is to investigate the capability of g-SiC and g-SiC2 siligraphenes in detecting H2S gas through diverse sensing mechanisms, using density functional theory. Our calculations demonstrate that the adsorption of H2S molecules onto both siligraphenes is a physical and exothermic process. The physical adsorption process helps sensing materials to recover soon (a few nanoseconds) after gas removal at room temperature. Investigation of geometric and electronic properties of g-SiC and g-SiC2 in combination with H2S molecule shows that both materials have the gas-detection ability through thermal- and resistance-based mechanisms. For example, the electrical conductance of g-SiC changes by 38% due to gas adsorption. In addition, the presence of H2S molecule on the g-SiC surface, changes the type of its majority carriers and makes it possible to use this material in Seebeckeffect-based H2S sensors. Overall, various sensing mechanisms besides short recovery time, make g-SiC and g-SiC2 great candidates to be used in H2S gas sensor as sensing material.