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Graphene grown by chemical vapor deposition has excellent mechanical, thermal and electrical properties, and has become the preferred material for a new generation of nanodevices. Theoretical research on the electronic properties of graphene will prompt the development and application of nanodevices. Based on the combination of density functional theory and non-equilibrium Green's function, the electronic structure characteristics of graphene and graphene/boron nitride with AA vertical stack structures were studied systematically in this paper. The results show that the band gap is zero at the high symmetry K point. In the range of 50 K to 400 K, the mobility of graphene decreases significantly with increasing temperature due to the electron-phonon interaction on Fermi surface. In addition, the characteristic analysis of energy band structures, density of states and electron density of graphene/boron nitride with different interlamellar space indicates that with the increase of layer spacing, the energy band gap decreases, and the energy difference between the conduction band and the valence band decreases. And increasing the number of atoms, the regularity of the change of the band gap opening between supercell and protocell structure of graphene / boron nitride is consistent, this can serve an guideline for the structural design of graphene-based devices. [ABSTRACT FROM AUTHOR]

Tr ithis paper, the growth of graphene on sapphire substrate was studied by the experimental preparation and simulation using chemical vapor deposition (CVD) method 􀀀 which focused on the effect of substrate surface morphology and growth temperature. The microstructure of graphene was investigated by atomic force microscope (AFM),X-ray diffraction (XRD) ？ field emission scanning electron microscope (FESEM) ？ Raman spectroscopy (Raman),and high resolution transmission electron microscope (HRTEM) respectively. The simulation results indicated that hydrogen had an important influence on the surface morphology of the substrate. Under the action of H atom ? the Al-() bond was elongated by 51.42% ? which was almost fractured ？ and it affected the surface roughness of the sapphire substrate. Tt was found that H had an etching effect on the surface of sapphire substrate？ and the surface roughness Ra of the etched sapphire substrate became larger, which made it difficult to grow graphene. When the growth temperature increased 􀀀 the quality of the graphene also became better. [ABSTRACT FROM AUTHOR]

In this paper, graphene was synthesized on sapphire substrate by chemical vapor deposition (CVD) method, and the effect of growth time on hydrophobic properties and microstructure of graphene was investigated. Contact-angle meter, Fourier transform infrared spectrometer, Raman spectrometer and field emission scanning electron microscopy were applied to study hydrophobic and microscopic structure of graphene, respectively. It shows that after growing 30 min, maximum contact angle of graphene is 129.96°, it presents hydrophobic properties. Meantime, infrared test shows only carbon-carbon double bonds. Raman analysis also indicates three characteristic peaks of graphene after growing 10-30 min. larger contact angle makes graphene as a potential hydrophobic material, and it can even be a promising superhydrophobic material by its hydrophobic modification. [ABSTRACT FROM AUTHOR]