First-principles studies of the energetic and electronic properties of charged defects, dopants, and complexes in 2D metal chalcogenides

Two-dimensional (2D) semiconducting materials have attracted extensive research interests for applications in optoelectronics, spintronics, photovoltaics, and catalysis. Realizing their potential in such applications requires a good understanding of the effects of defects, dopants, and impurities on the properties of these systems. We perform density functional theory (DFT) calculations to accurately compute formation energies, charge transition levels, and electronic properties of dopants, defects, and complexes in the technologically important 2D semiconductor materials focusing on the metal chalcogenides MoS₂, WSe₂, and SnS. We investigate the dependence of computed defect properties on different levels of theory, utilizing a correction scheme to ensure appropriate electrostatic boundary conditions for charged defects in 2D materials. Some defects induce structural distortions, e.g., Jahn-Teller and other lattice reconstructions, which alter the electronic properties. We identify dopants which bind with intrinsic defects to form complexes, passivating the dopants and rendering them less effective. Finally, we demonstrate how theoretical predictions based on DFT and beyond-DFT approaches such as GW and BSE can help inform the interpretation of experimental results.