▎ 摘　　要

NOVELTY - The method involves setting the space group P6/mmc, the lattice constant is: b=a, gamma=120degrees. The WSe2 bulk material model is established, and the WSe2 bulk material has a layered structure. The space group is provided as P6/mmm, the lattice constant as b=a, gamma=120degrees. A graphite model is established, where graphite has a layered structure. The WSe2 bulk material model is dissected into the (001) crystal plane to obtain a single-layer WSe2. The graphite model is dissected into the (001) crystal plane to obtain graphene. A 4x4 graphene supercell is created based on the graphene, and a 3x3WSe2 supercell is created based on the single-layer WSe2. The 3x3WSe2 supercell is superimposed vertically on the 4x4 graphene supercell to obtain a graphene or tungsten diselenide-based heterojunction gas sensor model. The model building was performed on MaterialsStudio 8.0 software. USE - Method for constructing heterojunction gas sensor model based on graphene or tungsten diselenide used for detection of gas molecule such as vehicle exhaust gas or toxic gas discharged by industrial waste gas. ADVANTAGE - The method enables to construct a hetero-junction gas sensor model based on graphene/tungsten diselenide, which has high stability of gas adsorption on the heterojunction, band structure and charge transfer from the theory. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the graphene or tungsten selenide heterojunction structure diagram.