Sensitivity enhancement of stanene towards toxic SO2 and H2S

Adsorption of S-containing gases on pristine, defective, and heteroatom doped stanene is studied for gas sensing applications by van der Waals corrected density functional theory. SO2 and H2S gas molecules are found to bind to pristine stanene too weakly to alter the electronic properties sufficiently for efficient gas sensing (binding energy of -0.20 and -0.33 eV, respectively). We demonstrate that vacancies and heteroatom doping can enhance the binding energy to - 1.67 and - 0.74 eV, respectively. It is found that presence of mono-vacancies, tri-vacancies, and In dopants at low concentrations in stanene results in considerable variations of the electronic properties in contact with S-containing gases, thus transforming stanene into an efficient sensing material.