|Research progress on self-organized growth of graphene on diamond|
|Release time: 2017-1-16|
| How to form a large area of high quality graphene on an insulating substrate is still a problem. Therefore, whether it is exploring a new method for preparing graphene, or finding a suitable substrate material for growing graphene, so that the novel physical properties of graphene can be displayed at room temperature, it is urgent to solve the basic research and device application of graphene. The problem. Diamond is an insulating material that combines many excellent properties. If graphene can be prepared on a diamond substrate, compared to other substrate materials, it will be conducive to exhibiting the special mechanical, thermal, electrical, and optical properties of graphene at room temperature. Performance is an ideal structure for building novel functional devices of graphene. But so far, there have been few reports on the direct preparation of graphene on the diamond surface. |
Recently, Researcher Gu Changzhi, Institute of Physics, Chinese Academy of Sciences / Beijing National Laboratory for Condensed Matter Physics, Li Wuzhen, Li Junjie, etc., and Xu Lifang, Quantum Science Simulation Center, Associate Professor Xu Jing of Renmin University of China, and Rensselaer Polytechnic Institute In cooperation with Professor Zhang Shengbai of the School, he first started with material design and theoretically predicted that the diamond (111) surface could achieve a phase transition from diamond structure to graphene structure under the induction of B atoms. After that, experiments verified single crystal diamond ( 111) The surface can be self-organized to form high-quality graphene under the condition of B doping, and the number of layers can be controlled.
Based on first-principles theoretical calculations, they simulated the effects of different boron doping concentrations and positions on the diamond surface reconfiguration. The results show that the fifth layer of boron doping directly caused the structural phase transition from diamond to graphite. The first double layer of the) plane is completely sp2 converted into a single layer of graphite and completely detached from the underlying structure. The single-layer graphene thus formed has a CC bond length of 1.45 ? in the layer and a distance of 3.30 ? from the underlying substrate. This is very close to the bond length in the graphite layer of 1.42 ? and the graphite layer spacing of 3.35 ?, indicating the existence of a diamond-graphene phase transition. This structural phase change is caused by the boron atoms incorporated in the fifth layer to enhance the surface reconstruction effect. After that, they adopted CVD method to realize the self-organized growth of graphene on the (111) surface of high-temperature and high-pressure (HPHT) diamond single crystal through the adjustment of boron doping and growth parameters. , Low defects, large area and high mobility. And by changing the growth conditions, graphene from single layer to double layer and multilayer can be prepared on the diamond substrate, which verifies the theoretical prediction well. This graphene material on a diamond substrate takes into account the many excellent physical properties of diamond and graphene, laying a foundation for the development of novel graphene devices.