We predict the CH4-sensing performance of monolayer MoX2(S, Se, Te) with X-vacancy, Mo-vacancy, and divacancy by the density functional theory (DFT). The results demonstrate that the combination of different sixth main group elements with Mo atom has different adsorption behaviors for CH4 gas molecule. Compared with MoX2, MVX, MVMo, and MVD generally exhibit better adsorption properties under the same conditions. In addition, different defects will have different effects on adsorption behavior of the systems, the MVD(MoTe2) has the better adsorption, the better charge transfer, and the shortest distance in these systems. The results are proposed to predict the CH4 gas molecule adsorption properties of MVD(MoTe2) and would help in guiding experimentalists to develop better materials based on MoX2 for efficient gas detection or sensing applications.
Keywords: Adsorption energy; Band gap; CH4 gas molecule; Charge transfer; DFT; Monolayer MoS2; Sensor.