KERI Directly Grows Multilayer Graphene at Room Temperature, Paving the Way for Composite Conductor Manufacturing [Reading Science]

Epitaxy Growth Achieved with Proprietary "K-sputtering"

Enables Repeated Stacking of Copper and Graphene

Anticipated Application to Next-Generation Composite Conductors

A technology that enables the direct growth of graphene on a substrate at room temperature, without the need for high heat, has been developed. By utilizing sputtering equipment widely used in current industrial settings, it is possible to fabricate everything from single or few-layer graphene to multilayered graphite. This technology is expected to be applied to manufacturing next-generation, high-performance composite conductors.

On September 27, the Korea Electrotechnology Research Institute (KERI) announced that the research team led by Dr. Hoseop Kim of the Power Cable Research Center and researcher Suhyun Nam had successfully achieved the direct growth of graphene-based thin films at room temperature using the proprietary “K-sputtering” apparatus they developed.

Schematic diagram of the thin film deposition principle using direct current (DC)-based K-sputtering. Provided by the research team

Graphene is a thin material where carbon atoms are arranged in a honeycomb pattern. Its superior electrical and thermal properties mean that, when combined with existing metals such as copper, it can be used to produce high-performance conductors that reduce power loss and heat generation. With increasing power demand from the electric vehicle and artificial intelligence (AI) data center sectors, the need for such composite conductors is also rising.

The challenge lies in the manufacturing process. Producing high-quality graphene through conventional chemical vapor deposition (CVD) methods requires high temperatures, and the graphene must then undergo a separate “transfer process” to be placed onto other materials. This has hindered large-area applications and the repeated stacking of metals and graphene in multiple layers.

‘Epitaxy Growth’ by Controlling Carbon Atom Arrangement

The research team focused on sputtering, a technique widely used in the semiconductor and display industries. Sputtering involves knocking tiny particles from a material and stacking them onto a substrate. However, when depositing carbon by sputtering, the atomic arrangement easily becomes disordered, forming amorphous films, which has limited the formation of graphene with a regular structure.

By analyzing the flow and behavior of carbon particles during the sputtering process, the team identified the factors that hinder graphene structure formation. They then developed a direct current (DC)-based K-sputtering system and process that allows for the control of the arrangement of carbon atoms on the substrate.

The key breakthrough was realizing “epitaxy growth,” which enables carbon atoms to be regularly arranged in alignment with the crystal structure of the substrate. As a result, the team succeeded in directly growing everything from single or few-layer graphene to multilayered graphite thin films at room temperature, all without extra heating steps. According to the research team’s study, this is the first time the epitaxy growth of such carbon thin films has been achieved via conventional sputtering methods.

The team verified the structure and properties of the fabricated thin films using cross-validation methods such as Raman spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD), in collaboration with Professor Junho Kim’s team at Incheon National University and Professor Sehee Lee’s team at Kyungpook National University.

Dr. Hoseop Kim of KERI (left) and researcher Suhyeon Nam are posing while holding a substrate coated with graphene. Provided by KERI

This technology is significant in that it enables metals like copper and graphene to be alternately deposited repeatedly in a single device, without a separate transfer process. The research team expects that by scaling up the technique for large-area, continuous production, this could lead to practical applications in manufacturing high-performance graphene-metal composite conductors for power devices.

Dr. Kim stated, “After much trial and error, we have experimentally demonstrated that it is possible to form graphene-based thin films with regularly aligned carbon atoms using the sputtering method.” He added, “We plan to upscale the equipment and develop a continuous production process, ultimately aiming to commercialize high-performance composite conductors for power equipment that feature alternating layers of copper and graphene.”

The research findings were published in the international journal “Surface & Coatings Technology,” which specializes in the field of material surface and coatings. The research team has also filed three domestic and one overseas patent application related to this technology.

This content was produced with the assistance of AI translation services.