Strain-modulated gas sensing properties of As6/Sb6 lateral heterostructures by first-principles calculations

Two-dimensional materials used for gas-sensing can be classified as donors or acceptors based on the different directions of electronic transfer. Meanwhile, external strain, by disrupting the balance of forces between the electrons, significantly impacts the electron transfer process between the material and gas molecules, thereby altering the gas-sensing properties. In this paper, single-layer As6/Sb6 lateral heterojunctions (LHSs) with armchair or zigzag (ZZ) interfaces have been constructed. The NO2 molecule and NH3 molecule are adsorbed on these LHSs, making LHSs act as donors or acceptors, respectively. The adsorption properties before and after applying different types of strain are calculated by first principles. Notably, the compressive strain exacerbates the structural deformation of all LHSs. In addition, the compressive strain promotes the charge transfer for NO2 sensing but hinders the charge transfer for NH3 sensing. The adsorption energy and charge transfer of NO2 adsorbed on As6/Sb6 ZZ-LHSs with compression strain are the largest, indicating the great potential for NO2 sensing. This work lays the foundation for designing and predicting high gas-sensitivity gas sensing materials.