On October 17, it was learned from the Ministry of Science and Technology that graphene, as a typical quantum material, has become a very important research direction in the field of condensed matter physics and has been highly valued by the domestic and foreign industrial fields. The European Union has launched a flagship research program for graphene. The United States, Japan, and South Korea have also increased investment in the basic research of graphene applications. Graphene is used as an additive in new energy sources, new materials, etc. However, little progress has been made in applications such as optoelectronic devices. The main technical bottleneck is that the growth rate of existing large monocrystalline graphene is lower than 0.4 μm/s. It takes several days to grow a wafer-level sample, making it difficult to obtain large-size graphene single crystals.
Recently, the research team led by Academician Yu Dapeng has made significant progress in the growth of large monocrystalline graphene. The CVD method is used to pyrolyze the methane gas at around 1000°C and put it on a polycrystalline copper substrate. The growth rate of the graphene single crystal was increased 150 times to 60 μm/s.
The core of this major breakthrough is to place the polycrystalline copper sheet on the oxide substrate (the gap between the two is 15μm). The oxide substrate provides continuous active oxygen for the surface of the copper sheet, which significantly reduces the potential for methane decomposition. The barrier (reduced from 1.57 eV to 0.62 eV) can efficiently catalyze the reaction on the copper surface and increase the graphene growth rate. Using this technique, it is possible to grow 300 μm graphene large single crystal domains within 5 seconds. The research results provide the necessary scientific basis for the controllable and high-speed growth of graphene single crystals with larger sizes. It provides an important scientific basis for breakthrough large-size single crystal production technology, and has great scientific and technical value.
This research was published on Nature Nanotechnology on August 8, 2016. This research has been continuously funded by the Ministry of Science and Technology and the National Natural Science Foundation of China; this research has also received the "Collaborative Innovation Center for Quantum Substance Science" (2011), the State Key Laboratory of Mesoscopic Physics, and the Electron Microscope Laboratory of Peking University. The unit's strong support.
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