Rice University researchers have found a way to stitch graphene and hexagonal boron nitride (h-BN) into a two-dimensional quilt that offers new paths of exploration for materials scientists.
The technique has implications for application of graphene materials in microelectronics that scale well below the limitations of silicon determined by Moore's Law.
New research from the lab of Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry, demonstrates a way to achieve fine control in the creation of such hybrid, 2-D structures.
Layers of h-BN a single atom thick have the same lattice structure as graphene, but electrically the materials are at opposite ends of the spectrum: h-BN is an insulator, whereas graphene, the single-atom-layer form of carbon, is highly conductive. The ability to assemble them into a single lattice could lead to a rich variety of 2-D structures with electric properties ranging from metallic conductor to semiconductor to insulator.
Because graphene is a conductor and h-BN is an insulator, the proportion of one to the other determines how well this new material conducts electrons. Lijie Ci and Li Song, both postdoctoral research scientists in Ajayan's lab, found that by putting down domains of h-BN and carbon via chemical vapor deposition (CVD), they were able to control the ratio of materials in the film that resulted.
Ci and Song are primary authors of a paper about the work that appeared in the online edition of Nature Materials this week.
Ajayan said the discovery is thrilling for a materials scientist.
"From a graphene perspective, it now gives us an opportunity to explore band-gap engineering in two-dimensional layered systems," he said. "The whole phase diagram of boron, carbon and nitrogen is fascinating, unexplored and offers a great playground for materials scientists.
|Contact: David Ruth|