Structure and property study by first-principles calculations: Two-dimensional semi-hydrogenated-semi-oxidized bilayer BN (111)-oriented nanosheets

Based on first-principles calculations, we investigate the structural, electronic and magnetic properties of semi-hydrogenated-semi-oxidized two-dimensional (111)-oriented bilayer BN nanosheets. Oxidation of the N-end surface is helpful for stabilizing the thinnest unhydrogenated nanosheet; however, oxidation of the B-end surface reconstructs the structure into irregular polygons, which represent c-BN bulk characteristics that are no longer present. H-BN-O structures are ferromagnetic semiconductors with a band gap larger than that of H-BN and smaller than that of c-BN. Our calculation results show that experimentally, for a few layers, the B (N) atoms of BN nanosheets are more easily bound to H (O). This result provides a good theoretical basis for the experimental synthesis of two-dimensional BN nanosheets and provides new ideas for achieving high performance BN-based electromagnetic nanodevices. [Display omitted] •By first-principles calculations, the structures, electronic and magnetic properties of two-dimensional (2D) bilayer semi-hydrogenated (111) BN nanosheets are investigated dependent on the oxygen passivity on the other surface side.•For the thinnest cubic BN nanosheets of (111)-oriented with the layer number n=2,•the original H-BN nanosheets reconstructed into planer layers without the bond between the two layers, while oxygen passivity on the un-hydrogenated surface side can help the structures maintain the bulk cubic BN phase.•The bilayer nanosheets of H-BN-O can open the band gap of H-BN, which the band gap changes can be from 1 eV to 2.3 eV because of the distribution of the electrons.•The H-BN-O structures are ferromagnetic semiconductor and the mostly magnetic moments are distributed on the outside N-end surface, it because of two outermost surface sides are asymmetric due to different electronegativity between B and N atoms.