IBS creates single-crystal metal substrates larger than A4 paper
Successful diversification of high-performance two-dimensional material synthesis materials


A research team led by Professor Feng Ding (a distinguished professor at UNIST) and group leader of the Center for Multidimensional Carbon Materials at the Institute for Basic Science (IBS), together with researchers from China and Switzerland, has succeeded in diversifying the surface pattern of a metal substrate for the synthesis of high-performance two-dimensional materials such as graphene.

Two-dimensional single-crystal materials, characterized by a regular arrangement and orientation of atoms, exhibit excellent thermal and electrical conductivity, making them suitable for use in high-performance electronic devices. However, the limited variety of single-crystal metal thin-film patterns required for the synthesis of two-dimensional single-crystal materials has been a challenge. This research synthesized a large-area (39×21㎠) single-crystal metal thin-film with approximately 30 different surface patterns.

The joint research team published a paper in Nature last May proving that the metal substrate used in material manufacturing holds the key to large-area single-crystal material production. They found that the orientation of the synthesized material varies depending on the substrate's Miller index (an index that describes the pattern of the metal substrate).

This study presents a method for synthesizing metal substrates with various Miller indices. First, a copper single crystal was cut to obtain fragments (seeds) with the desired pattern. The surface pattern varies depending on the direction in which the crystal is cut, much like the marbling of beef.

The fragments were then attached to a copper polycrystal and annealed for several hours at a high temperature (1020°C), close to its melting point. During this process, the crystals surrounding the fragment rearranged themselves into a pattern that mirrored the fragment's shape, gradually expanding over a wider area. Ultimately, the film transformed into a single crystal with a consistent pattern across the entire film.

Utilizing the developed technology, large-scale synthesis of metal thin films with diverse surface patterns is possible. With the expanded range of substrate options, selecting the appropriate substrate and controlling the orientation of the desired material is expected to enable the synthesis of high-performance two-dimensional materials with desired properties. For example, it is possible to manufacture substrates that can be folded or bent and used in foldable phones.

The research team expects that various metals, including the copper and nickel used in this study, can be manufactured in the form of large-area single-crystal metal thin films.

“The production of large-area single-crystal metal thin films with various crystal planes has been a long-standing goal in the field of materials science,” said Feng Ding, IBS group leader. “The large-area single-crystal metal thin films synthesized through this research can be used in various fields, such as as templates for the synthesis of various single-crystal two-dimensional materials and as catalysts that selectively induce only specific chemical reactions.”

The Ministry of Science and ICT and the IBS announced that the results of this study were published in the online edition of Nature (IF 43.070) at 00:00 on May 28, Korean time.