▎ 摘 要
One of the most challenging issues for a gas sensor is to achieve high selectivity when detecting the presence of particular gases in media mixed with other gases. A straightforward solution is to develop the sensing materials that can discriminate among several analytes in a mixture. Here we perform first-principles calculations for the adsorptions of common air pollutants and typical volatile organic compounds on Si-doped graphene and find that the adsorption strength of formaldehyde molecule is much stronger than those for other gas molecules. We further calculate the current-voltage curves by the nonequilibrium Green's function method. The electronic transport results show that the average responses of nano-sensors constructed from Si-doped graphene are 29.3% and 27.9% along the armchair and zigzag directions, respectively. The present study indicates that Si-doped graphene can be potentially applied to formaldehyde gas sensing with high selectivity and sensitivity.