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CEMAS essential to research featured on cover of Nature

The Ohio State University’s capacity in high-end microscopy has landed on the cover of Nature. Scholars at Ohio State’s Center for Electron Microscopy and Analysis (CEMAS) teamed with colleagues at the Massachusetts Institute of Technology and the Masdar Institute of Science and Technology on the research, which promises a significant cut in costs of wafer technology.

“The new technology enables epitaxial growth of single crystal semiconductor films remotely through a single sheet of graphene,” said Jinwoo Hwang, an assistant professor of materials science and engineering who led CEMAS’s participation in the project. “This can lead to new technological breakthroughs, including defect-free epitaxial growth of semiconductor thin films, and recycling and reuse of expensive substrates that have been difficult in the past.”

Epitaxy describes the process depositing one single crystalline material onto another single crystal material. “The deposition happens gradually in a chamber, so we usually say we ‘grow’ the film,” Hwang said. “Epitaxial growth of semiconductor thin films is one of the most important processes when you make any semiconductor devices, like memory chips, computer processors, solar cells, and etc.”

In an epitaxial growth, the deposited film is fixed in a crystallographic orientation with respect to the substrate crystal, which acts as a seed material. If the orientation of the film is random with respect to the substrate, epitaxy hasn’t taken place.  

“What we showed in this work is that the epitaxial growth of the film is still possible even when we place a single sheet of graphene, a layer of carbon with hexagonal lattice, on top of the substrate, before the growth,” Hwang said. The graphene layer in between the materials allows us to separate the grown film from the substrate after growth. This allows us to reuse the substrate for the growth of another film. So, it enables the recycle and reuse of the substrate, which is especially beneficial when the substrate is made of some exotic materials, and consequently, expensive.

Jared JohnsonProfessor Jinwoo HwangHwang and graduate student Jared Johnson using the world-class, high-resolution electron microscopy facility at CEMAS were able to demonstrate directly the remote epitaxy at the graphene interface at the atomic scale.  

Professor David McComb, director of CEMAS said “This is a great example of how the world-leading capabilities at CEMAS are being used to learn about new phenomena that have the potential to change the world.  CEMAS faculty and researchers are much sought-after collaborators for academic and industrial research organizations across the world.”

The research appears in the April 20 edition of Nature.