Many emerging cleantech materials — especially for batteries — are built from graphene, an ultra-thin and super-strong carbon-based material. Engineers at the University of Michigan developed what’s being called the first reliable, scalable method for growing high-quality, single layers of hexagonal boron nitride on graphene. The breakthrough could be transformational for creating materials that power smaller, more energy-efficient next-generation electronic devices and LEDs.

“The technology used to generate deep-UV light today is mercury-xenon lamps, which are hot, bulky, inefficient and contain toxic materials,” Zetian Mi, professor of electrical engineering and computer science, said in a news release. 

“If we can generate that light with LEDs, we could see an efficiency revolution in UV devices similar to what we saw when LED light bulbs replaced incandescents.”

The process

Graphene is the world’s thinnest, strongest electricity-conducting material. Hexagonal boron nitride is the world’s thinnest insulator. 

Combining hBN and graphene in smooth, single-atom layers reveals exotic properties. Orderly rows of atoms are more stable at high temperatures than disorderly, jagged formations, the researchers found. But previous research projects have struggled to create orderly layers when combining the two materials.

“To get a useful product, you need consistent, ordered rows of hBN atoms that align with the graphene underneath, and previous efforts weren’t able to achieve that,” said Ping Wang, postdoctoral researcher in electrical engineering and computer science, in the news release. “Some of the hBN went down neatly, but many areas were disordered and randomly aligned.” 

Mi’s lab developed the innovative process, created the material, and characterized the material’s interactions with light. They then collaborated with Ohio State University researchers to study the material’s structural and electrical properties.

Putting it to use

The exotic properties resulting from the smooth graphene-hBN combination could power deep-UV LEDs in devices such as lasers and air purifiers. The material also could enable more efficient information storage in quantum devices.

“Experimenting with large amounts of pristine hBN was a distant dream for many years, but this discovery changes that,” Mi said. “This is a big step toward the commercialization of 2D quantum structures.”