Study on the sensing characteristics of two-dimensional material WTe2 to toxic gases HF and Cl2

The adsorption characteristics of gas molecules HF and Cl-2 on monolayer WTe2 surface are studied by first-principles calculation method. The results show that monolayer WTe2 is more sensitive to gas molecule Cl-2. The adsorption performance of monolayer WTe2 to gas molecule HF cannot be improved by doping atoms. When the upward vertical electric field is applied, the sensitivity of monolayer WTe2 to gas molecule Cl-2 is improved, and when the downward vertical electric field is applied, the monolayer WTe2 shows an obvious desorption trend to gas molecule Cl-2. The vertical electric field cannot significantly enhance the interaction between gas molecule HF and Ag-doped monolayer WTe2. Our research confirms that monolayer WTe2 is more sensitive to gas molecule Cl-2 and can be improved or desorbed by the vertical electric field, while that of monolayer WTe2 for gas molecule HF cannot significantly change. Furthermore, the electrical transport characteristics of monolayer WTe2 and Cl-2-WTe2 system are studied to better explain the reason for the higher sensitivity to gas molecule Cl-2. The research results of this paper provide theoretical guidance for the experimental preparation of high sensitivity gas sensor based on two-dimensional transition metal dichalcogenide WTe2.