Scientists say they've taken a big step toward the creation of two-dimensional electronics by combining a conductor and an insulator in layers just an atom thick.
The materials - graphene and hexagonal boron nitride - have been merged into sheets and built into a variety of patterns at nanoscale dimensions. The work shows promise for the development of flexible electronics.
"It should be possible to make fully functional devices with circuits 30, even 20 nanometers wide, all in two dimensions," says Rice University researcher Jun Lou. This is about the same scale as is used in current semiconductor fabrication.
The potential of graphene for use in electronics has been obvious since its discovery ten years ago. But it's not enough by itself to build a working device: graphene-based electronics require similar, compatible 2-D materials for other components.
Hexagonal boron nitride (h-BN) looks like graphene, with the same chicken-wire atomic array. In the new work, the team first laid down a sheet of h-BN, over which laser-cut photoresistant masks were placed, and exposed material was etched away with argon gas.
After the masks were washed away, graphene was grown via CVD in the open spaces, where it bonded edge-to-edge with the h-BN. The hybrid layer could then be picked up and placed on any substrate.
While there's much work ahead to characterize the atomic bonds where graphene and h-BN domains meet and to analyze potential defects along the boundaries, Liu's electrical measurements proved the components' qualities remain intact.
Liu says the next step is to place a third element, a semiconductor, into the 2-D fabric. "We're trying very hard to integrate this into the platform," he says. "If we can do that, we can build truly integrated in-plane devices."