A reliable, scalable method for growing single layers of hexagonal boron nitride (hBN) on graphene has been developed. The process can produce large sheets of high-quality hBN with the widely used molecular-beam epitaxy process and could advance research in next-generation electronics and LED devices.
Graphene-hBN structures can power LEDs that generate deep-ultraviolet (UV) light and lead to smaller, more efficient lasers, air purifiers and other devices. Bonding hBN, the thinnest insulator available, and graphene together in smooth, single-atom-thick layers can also enable quantum computing devices and a variety of other applications.
Previous attempts to synthesize thin layers of hBN relied on methods like sputtering and chemical vapor deposition and struggled to achieve the even, precisely ordered layers of atoms needed to bond correctly with the graphene layer. Recognizing that neat rows of hBN atoms are more stable at high temperatures, researchers from Yale University, University of Michigan and Ohio State University experimented with molecular-beam epitaxy, an industrial process that entails spraying individual atoms onto a substrate.
A terraced graphene substrate was heated to around 1,600° C before spraying on individual boron and active nitrogen atoms. Neatly ordered seams of hBN formed on terraced edges of the graphene, which expanded into wide ribbons of material.
The process outlined in Advanced Materials marks progress toward the commercialization of 2D quantum structures.