Diamane Oxide. Two-Dimensional Film with Mixed Coverage and a Variety of Electronic Properties

Structural stability and electronic and mechanical properties of nitrogen- and boron-doped fluorinated diamane

In this work, the structural, electronic and mechanical properties of fluorinated diamane (F-diamane) with N and B dopants are systemically investigated using first-principles calculation. The N atom tends to stay in the external substituted site without F saturation, while the B-doped structure of the substituted external site with F saturation is the most stable. Ab initio molecular dynamics simulations confirm the thermal stability. The band structures of stable doped structures are similar to that of pristine F-diamane, due to the slight contribution of the dopant to the band edges. In addition, after the introduction of the B dopant, the formation energy reduces, and the transition barrier of graphene bilayers into diamane is smaller, indicating the feasibility of graphene bilayer fluoridation. Furthermore, we find that these doped structures have mechanical stability with isotropic elastic constants, Young's modulus, shear modulus and Poisson's ratio. Our work would promote the synthesis and development of two-dimensional diamane.

Formation of Diamane Nanostructures in Bilayer Graphene on Langasite under Irradiation with a Focused Electron Beam

In the presented paper, we studied bilayer CVD graphene transferred to a langasite substrate and irradiated with a focused electron beam through a layer of polymethyl methacrylate (PMMA). Changes in the Raman spectra and an increase in the electrical resistance of bigraphene after irradiation indicate a local phase transition associated with graphene diamondization. The results are explained in the framework of the theory of a chemically induced phase transition of bilayer graphene to diamane, which can be associated with the release of hydrogen and oxygen atoms from PMMA and langasite due to the "knock-on" effect, respectively, upon irradiation of the structure with an electron beam. Theoretical calculations of the modified structure of bigraphene on langasite and the experimental evaluation of sp³-hybridized carbon fraction indicate the formation of diamane nanoclusters in the bigraphene irradiated regions. This result can be considered as the first realization of local tunable bilayer graphene diamondization.