Density-functional study of hydrogen cyanide adsorption on silicene nanoribbons.

Adsorption of toxic hydrogen cyanide gas (HCN) on armchair silicene nanoribbons (ASiNRs) is investigated by the first principles method using density functional theory (DFT) to compute geometric, electronic, and transport properties. Two variants of ASiNRs are considered: pristine ASiNR (P-ASiNR) and defective ASiNR (D-ASiNR), which is created by introducing a vacancy in P-ASiNR by removal of a Si atom. Total energy optimizations are used to find the most stable structures. The calculated results reveal that although HCN is physisorbed in both variants, sensitivity in the case of D-ASiNR is sufficiently enhanced owing to more adsorption energy and charge transfer between the ASiNR-gas complex. Also, the inspection of current-voltage characteristics demonstrates that the introduction of defect has considerably increased the conductivity of ASiNR. Hence, D-ASiNR may be used as a promising sensor for HCN gas. Graphical abstract Transmission eigenstates of (a) Pristine ASiNR (b) Defective ASiNR after HCN adsorption.