Stacking experiment opens new prospects for graphene
But now, what once was just a theory could be a reality. An experiment conducted by Massachusetts Institute of Technology (MIT) researchers could be a step towards integrating a band gap in graphene.
The study is co-authored by Physics professor Ray Ashoori and Pablo Jarillo-Herrero, a Mitsui Career Development assistant professor of physics at MIT along with 10 others researchers.
The team placed a sheet of graphene on top of hexagonal boron nitride, which is also a material that is one atom thick and has similar properties with graphene. The resulting material shares graphene's remarkable ability to conduct electrons, while adding the band gap necessary to form transistors and other semiconductor devices.
"By combining two materials, we created a hybrid material that has different properties than either of the two," Jarillo-Herrero said.
Graphene is an extremely good conductor of electrons, while boron nitride is a good insulator, blocking the passage of electrons. "We made a high-quality semiconductor by putting them together," Jarillo-Herrero explained. Semiconductors, which can switch between conducting and insulating states, are the basis for all modern electronics.
To make the hybrid material work, the researchers had to align, with near perfection, the atomic lattices of the two materials, which both consist of a series of hexagons. The size of the hexagons (known as the lattice constant) in the two materials is almost the same, but not quite: Those in boron nitride are 1.8 per cent larger. So while it is possible to line the hexagons up almost perfectly in one place, over a larger area the pattern goes in and out of register.
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