Inligtingsbron: Skool vir Fisika

On May 27, 2020, Researcher Liu Kaihui, Academician Wang Enge of the School of Physics of Peking University, Academician Yu Dapeng of Southern University of Science and Technology, and Professor Ding Feng of the Ulsan Institute of Science and Technology in South Korea made important progress in the manufacturing of high-index single crystal copper foil. The research team creatively proposed the "variation and inheritance" growth mechanism regulated by the interface of the crystal surface, for the first time in the world to realize the manufacture of the most complete and largest size high-index single crystal copper foil library. Related research results were published online in the journal Nature with the title "Seeded growth of large single-crystal copper foils with high-index facets".

Koper speel 'n uiters belangrike rol in die moderne inligtingsamelewing en word wyd gebruik in sleutelvelde soos elektriese, elektroniese, kommunikasie en nasionale verdediging. Die kommersiële koper wat tans op die mark is, is egter basies polikristallyne koper, en verskillende defekte daarin veroorsaak dat die doeltreffendheid van elektron- en fonontransport aansienlik verminder word. In teorie kan enkelkristal koper met 'n perfekte kristalstruktuur die intrinsieke elektriese en termiese prestasie van koper maksimeer, en dit sal na verwagting 'n belangrike impak hê in die rigting van lae-verlies-, hoë-hitte-dissipasiekrag en toepassings van elektroniese toestelle. Daarbenewens word koper met die opkoms van tweedimensionele materiaalnavorsing die afgelope paar jaar baie gebruik in die epitaksiale voorbereiding van tweedimensionele enkelkristal-materiale. 'N Enkele kristal koperfoeliesubstraat met verskillende indeks kristalvlakke is die basis vir die epitaksiale groei van tweedimensionele enkelkristal materiale met verskillende strukture. Daarom is die voorbereiding van enkelkristal koperfoelie met kristalvlakke met groot en meervoudige indeks 'n wetenskaplike en tegniese probleem wat dringend opgelos moet word in die nywerheids- en wetenskaplike navorsing.

In materials science, single crystal copper foil can be divided into two categories according to the crystal plane index: low index crystal plane and high index crystal plane. As shown in Figure 1, there are only three types of low-index crystal planes: Cu (001), Cu (011), and Cu (111), while there are theoretically unlimited types of high-index crystal planes. Since 2016, Liu Kaihui and collaborators have made a series of progress in the research of low-index copper single crystals: ultra-fast epitaxial preparation of single-meter graphene single crystals on single crystal Cu(111) (Nature Chemistry 2019, 11 , 730; Science Bulletin 2017, 62, 1074; Nature Nanotechnology 2016, 11, 930); decimeter-scale two-dimensional hexagonal boron nitride single crystal epitaxy on the neighboring Cu(110) single crystal (Nature 2019, 570, 91 ). Compared with the low-index crystal plane, the high-index crystal plane copper foil can provide a richer surface structure, which can greatly broaden the types of epitaxial preparation of two-dimensional material systems. However, the traditional annealing method can usually only obtain the Cu(111) single crystal with the lowest surface energy, and the high-index crystal plane structure is not dominant in thermodynamics and kinetics, and its control preparation is extremely challenging.

In response to this problem, the research team developed a new annealing technology to achieve thermodynamic and kinetic control of the copper foil recrystallization process (Figure 2a). Different from the traditional annealing process, a layer of oxide can be formed on the surface of the copper foil through the designed pre-oxidation process. The formation of the interface between copper and copper oxide makes the traditional "minimum surface energy principle" no longer the main driving force for the formation of crystal planes. , So as to greatly increase the formation probability of high-index crystal plane "nucleus"; through the designed reducing atmosphere annealing process to eliminate the dynamic grain boundary, the abnormal growth of the high-index crystal plane "nucleus" can be achieved, thereby preparing A4 paper The size of the high-index crystal plane single crystal has more than 30 types of crystal planes (Figure 2b-c). At the same time, using the prepared single crystal copper foil as a "seed crystal" can induce the conversion of polycrystalline copper foil into a single crystal having the same crystal orientation as the "seed crystal", thereby realizing a large-size single crystal copper foil with a specific crystal plane Oriented "replication" manufacturing of single crystal copper ingots. In addition, this method is universal for the preparation of other single crystal metal foils.

Hierdie navorsingsprestasie is die eerste wat die beheerbare voorbereiding van die enkelkristal koperfoeliebiblioteek met die grootste grootte en die mees volledige kristalvlakindeks ter wêreld besef. In enkelkristalmetaalnavorsing is tweedimensionele materiaalgroei, oppervlak-koppelvlak-katalise, lae-verlies elektriese transmissie, hoë frekwensie. Die velde van stroombane en hoë hittebakke is van baanbrekende belang.

Wu Muhong, Zhang Zhibin, Xu Xiaozhi en Zhang Zhihong is die mede-eerste outeurs van die referaat, en Liu Kaihui, Ding Feng, Yu Dapeng en Wang Enge is die ooreenstemmende outeurs. Die navorsingsresultate is sterk ondersteun deur die Natural Science Foundation of China, die Ministerie van Wetenskap en Tegnologie, die Beijing Science and Technology Commission en ander verwante projekte, die Peking University State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, Collaborative Innovation Centre for Quantum Matter Wetenskap- en elektronmikroskooplaboratorium, ens.