Semi-metallic bilayer MS2 (M=W, Mo) induced by Boron, Carbon, and Nitrogen impurities

We performed the first-principle density functional theory (DFT) calculation to investigate the structural and electronic properties of the bilayer (BL) MS2 (M = W and Mo) with and without Boron (B), Carbon (C), and Nitrogen (N) impurities (added in the center between the slabs). We used the DFT method, which implemented in the Quantum espresso package, to calculate the electronic band structure, band gap, density of states (DOS), total energy, and chemical potential. In the pristine case, the BL structure of both WS2 (Tungsten disulfide) and MoS2 (Molybdenum disulfide) showed indirect electronic bandgap of 1.37 eV and 1.26 eV, respectively. A semimetal behavior with a zero-band gap was detected with (B, C, and N)-doped MoS2 and (B and N)-doped WS2 while a direct band gap of ∼0.1eV was revealed in the case of C-doped WS2. The electronic DOS for the BL WS2 and MoS2 were also calculated in the present of B, C, and N impurities. These impurities changed the shape and reduced the value of the DOS, which confirmed all the obtained results in this report. The aforementioned outcomes show the possibility of manipulating the structural properties of the MS2 materials for countless applications related to photo-and gas-sensing devices as well as energy storage related applications.