Converting graphene to a semiconductor

By arranging hydrogen molecules in a nano-pattern on graphene, Danish scientists have converted graphene to a semiconductor.

A special characteristic of graphene is that the carbon atoms sit in an ultra-thin layer just one atom thick. The layers of graphene are extremely strong and have an ability to conduct electricity at room temperature that is superior to all other known materials. Researchers at IBM recently demonstrated that computer chips made of graphene are much faster than the existing chips based on silicon.

Silicon has the important property that its ability to conduct electricity can be turned on and off. Materials with this capacity are called semiconductors, but unlike silicon, graphene is not a semiconductor in itself. If graphene is to replace silicon in future, it is therefore necessary to find methods for opening a so-called bandgap in the graphene and thereby converting it to a semiconductor.

Researchers at Aarhus University and Aalborg University are the first in the world to find a method to actually turn graphene’s conduction ability on and off. They have demonstrated that by making nano-patterns out of hydrogen molecules on a graphene surface, even the large sheets of graphene can be converted to semiconductors.

- We form the graphene layer on a metal crystal, and by adding a suitable amount of hydrogen that creates a nano-pattern arranged on the surface, we can open a bandgap. The hydrogen nano-pattern restricts the wave functions of the electrons and that’s what causes the bandgap opening, says Associate Professor Liv Hornekær, Department of physics and astronomy, Aarhus University in a press release.

The discovery by by scientists at the Department of Physics and Astronomy (IFA), the Institute for Storage Ring Facilities (ISA) and the Interdisciplinary Nanoscience Centre (iNANO) at Aarhus University, and the Department of Physics and Nanotechnology at Aalborg University was published on 14 March in Nature Materials.

Read the press release >>