An ab Initio Study\nof Carbon Impurities on Single-Layer\nMoS<sub>2</sub> for Optoelectronic Applications

In this study, we elucidate the efficacy of carbon impurities\non\nthe monolayer 2H-MoS<sub>2</sub>. First-principles investigation using\nthe density functional theory (DFT)-G<sub>0</sub>W<sub>0</sub>-Bethe–Salpeter\nequation (BSE) approach infers that carbon dopant and adatom on 2H-MoS<sub>2</sub> are essential in creating excitonic reconfiguration. 2H-MoS<sub>2</sub> with 25.00% carbon dopant shows Wannier–Mott exciton\nakin to pure 2H-MoS<sub>2</sub> with narrower bandgap energy, which\ncan provide absorption in the near-infrared range. Additionally, large\nexcitonic reconfiguration toward the Frenkel-like exciton is observed\non 2H-MoS<sub>2</sub> with 11.11% carbon dopant and 11.11% carbon\nadatom. This strong exciton binding and large exciton mass character\nsuggest that 2H-MoS<sub>2</sub> with carbon impurities is of the essence\nfor photovoltaic and other optoelectronic applications.