Realization of efficient and selective NO and NO₂ detection via surface functionalized h-B₂S₂ monolayer

In the ever-growing field of two-dimensional (2D) materials, the boron-sulfide (B₂S₂) monolayer is a promising new addition to MoS₂-like 2D materials, with the boron (a lighter element) pair (B₂ pair) having similar valence electrons to Mo. Herein, we have functionalized the h-phase boron sulfide monolayer by introducing oxygen atoms (Oh-B₂S₂) to widen its application scope as a gas sensor. The charge carrier mobilities of this system were found to be 790 × 10² cm² V^-1 s^-1 and 32 × 10² cm² V^-1 s^-1 for electrons and holes, respectively, which are much higher than the mobilities of the MoS₂ monolayer. The potential application of the 2D Oh-B₂S₂ monolayer in the realm of gas sensing was evaluated using a combination of density functional theory (DFT), ab initio molecular dynamics (AIMD), and non-equilibrium Green's function (NEGF) based simulations. Our results imply that the Oh-B₂S₂ monolayer outperforms graphene and MoS₂ in NO and NO₂ selective sensing with higher adsorption energies (-0.56 and -0.16 eV) and charge transfer values (0.34 and 0.13e). Furthermore, the current-voltage characteristics show that the Oh-B₂S₂ monolayer may selectively detect NO and NO₂ gases after bias 1.4 V, providing a greater possibility for the development of boron-based gas-sensing devices for future nanoelectronics.