'Hybrid' Graphene Obtained

By combining the atom-thick carbon compound graphene with very small sheets of hexagonal boron nitride (h-BN), researchers at the Rice University managed to obtain a new type of structure that is bound to advance materials science considerably. The investigators produced a two-dimensional quilt, which essentially overlaps two honeycomb-like materials on top of each other. Analysts say that the new compound is very likely to revolutionize a large number of research fields in materials science.

But undoubtedly one of the main applications for the new finding would be the scaling down of electronic components, far below the maximum level of miniaturization which was predicted through Moore's Law. The field of microelectronics could therefore receive a significant boost, at a time when the industry is struggling with the limitations that working with extremely small transistors entail.

The Rice team, which was led by the university's Benjamin M. and Mary Greenwood Anderson professor in mechanical engineering and materials science, and of chemistry, Pulickel Ajayan, also managed to demonstrate methods of achieving total control over the new 2D structures. He explains that the most amazing possibility the new hybrid provides is the fact that it can act as a metallic conductor, a semi-conductor, and an insulator, depending on needs. The professors say that the secret lies within the way the two components interact.

Both graphene and h-BN have the same, honeycomb-like hexagonal structure, and they overlap neatly on top of each other. What differs considerably is the amount of electricity each can carry. While graphene is a very apt conductor, h-BN isolates with great efficiency. Therefore, combining the two in various patterns could result in 2D materials that either stop or allow electricity through, a crucial need in the electronics industry.

“From a graphene perspective, it now gives us an opportunity to explore band-gap engineering in two-dimensional layered systems. The whole phase diagram of boron, carbon and nitrogen is fascinating, unexplored and offers a great playground for materials scientists. This is only the first instance showing that these structures can indeed be grown in 2-D like graphene. I think the whole new field will be exciting for basic physics and electro-optical applications,” says Ajayan. Details of the work conducted at Rice will be published in this week's issue of the respected scientific journal Nature Materials.