To achieve more than 30 kinds of high-index planes, A4 size paper for producing a single crystal copper breakthrough library

2020 May 27, Peking University researcher Liukai Hui, YU Dapeng Wang Enge academician with the Chinese Academy of South University of Technology, Ulsan, Korea Institute of Science and Technology, Professor Feng Ding cooperation has made significant progress in the direction of single crystal copper foil manufacturing high index. \”Genetic variation and\” growth mechanism research team proposes a creative crystal table interface control, first in the world to achieve the most complete varieties, the size of the largest manufacture of single crystal copper library of high index facets. Relevant research results to \”Seeded growth of large single-crystal copper foils with high-index facets\” in the title published online in \”Nature\” magazine. Copper plays an extremely important role in the modern information society, it is widely used in key areas of electrical, electronic, communications, defense and so on. However, the commercial use of copper on the market basically polycrystalline copper, resulting in a variety of electronic defects which existed, dramatically reducing the phonon transport efficiency. In theory, a perfect single crystal copper crystal structure may have the intrinsic electrical and thermal properties of copper to the limit, it is expected to have significant impact in the direction of low loss, high power dissipation, the electronic device applications. Further, research in recent years with the rise of two-dimensional material, copper is widely used in the preparation of a two-dimensional epitaxial single-crystal material. A single crystal substrate of copper foil with a variety of crystal plane indices of different structures is the basis of a two-dimensional single crystal material epitaxially grown. Therefore, the preparation of large size, a variety of single-crystal copper index crystal plane of the industry, the research community urgently to address scientific and technical issues.

In materials science, the crystal plane index press foil can be divided into two categories: low-index planes and high index facets. As shown in FIG. 1, (111) in which only the three kinds of Cu low index crystal plane (001), Cu (011), Cu, and the high index facets theoretically limitless. Since 2016, Liukai Hui and collaborators has been made on a copper single crystal of low index planes of a series of developments: of meter class Ultrafast epitaxial graphene single crystal (Nature Chemistry 2019 is implemented on a single crystal Cu (111), 11 , 730; Science Bulletin 2017, 62, 1074; Nature Nanotechnology 2016, 11, 930); (110) decimeter dimensional hexagonal boron nitride single crystal epitaxial prepared (Nature 2019, 570, 91) implemented on a single crystal neighbor Cu. Compared with low-index planes, the high index facets provide a richer copper foil surface structure can greatly expand the kind of two-dimensional material prepared epitaxy system. However, conventional methods typically only get annealing lowest surface energy of the Cu (111) single crystal high index crystal plane structure on the thermodynamics and kinetics are not dominant, controlling preparation challenging.

To solve this problem, the research team developed a new annealing technology, the copper process control thermodynamic and kinetic (FIG. 2a) foil recrystallization. Different from the conventional annealing process, the copper foil surface may be formed by preoxidation process design layer of oxide, copper and copper oxide interface is formed such that a conventional \”principle lowest surface energy\” is no longer a major driving force of crystal planes formed , thus greatly improving the probability of forming the high index facets \”core\”; annealing process by reducing atmosphere designed to eliminate grain boundary kinetics may be achieved this high index facets \”core\” of the abnormal growth, thereby preparing a sheet A4 high index planes of single crystal size, the type of crystal face as many as 30 species (FIG. 2b-c). Meanwhile, the single crystal prepared as a single crystal copper \”seed\”, can be induced into the polycrystalline copper \”seed\” crystal having the same crystal orientation, in order to achieve a specific crystal plane of the large-size copper orientation of the single crystal copper ingots and \”copy\” manufactured. Furthermore, the method is universal preparing monocrystalline metal foil other pair. The findings for the first time the world\’s largest size controlled preparation of plane index most complete library of single crystal copper, a metal single crystal study, the growth of two-dimensional material, the catalytic surface and interface, low loss electrical transmission frequency field of the circuit board, and the like, high heat dissipating pioneering sense. Wumu Hong, Zhang Zhibin, Xu Zhi, Zhang Zhihong is co-author of the paper, Liukai Hui, Ding Feng, YU Dapeng, Wang Enge corresponding author for the paper. The research results have been NSFC, Science and Technology, Beijing Municipal Science and Technology Commission and other related projects and Artificial Microstructure and Mesoscopic State Key Laboratory of Physics, Physical Science Collaborative Innovation Center quantum and electron microscopy laboratory of Peking University support .