| Owing to the peculiar structure and characters, graphene has been an intercross hotspot in various areas, such as Physics , Materials, Chemistry, Information, Biotechnology and other field since it was exploited successfully in 2004. Graphene gets remarkable features of tiny volume, quantum size effect and so on. Moreover, its unique structure and strong covalent bond between atoms determine the difference to ordinary two-dimensional physical system characteristics. Owing to its particular structure, graphene gets many superior and unique characters in physical, chemical, and mechanical properties. Therefore, it has a wide application prospect in micro/nano electronic devices, optoelectronic devices, spin quantum components and new composite materials.The first-principle calculations software CASTEP, which is based on the Density Function Theory (DFT), was taken to calculate the effect of single vacancy defect and SW defect on the electronic structure of bilayer graphene. First a supercell was constructed, the structure of which was optimized, and then the related properties were calculated. Also a comparative analysis of band structure and electronic state density between perfect bilayer graphene and bilayer graphene with defects were given. The influences of different imperfection on system were obtained, bilayer graphene with vacancy defect presents magnetism, and bilayer graphene with SW defect shows a tiny band gap, and the Fermi energy moves down in both cases, making the system became metallic. Combining with the Atom Local density of states, the shift down of Fermi level were further explained.Besides, Molecular Dynamics Simulation was taken to investigate the mechanical properties of bilayer graphene. The mechanical properties of perfect structure and structure with defects were computed under different temperatures. The related mechanical parameters, such as Young's modulus, elastic constants, bulk modulus etc. were acquired. The obtained results were compared and analyzed. |
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