Milestone in synthetic graphene production

Very fast electronic circuits, flexible display screens and efficient solar cells; the promises of graphene are plenty. This material, which consists of a single layer of carbon atoms bonded in a hexagonal pattern, is one of the fastest semiconductors, and it is strong, flexible and light.

Since graphene was discovered in 2004 scientists have been looking frantically for ways to produce it as purely as possible. Only in its purest form can electrons move freely through the atomic lattice, a phenomenon called ballistic transport. Defects, impurities and grain boundaries induce scattering, preventing ballistic transport. Producing the material on the appropriate substrate and in large quantities has also proven a tough nut to crack.

Delft researchers from Professor Guido Janssen’s surface and interface group (MMME faculty) and from Professor Lieven Vandersypen’s quantum transport group (AS faculty) tackled these challenges. They fabricated the material with a very high quality using a technique called chemical vapor deposition (CVD) – a technique often used in the semiconductor industry to produce thin films.

An article about this achievement was published last month in Applied Physics Letters. The first authors are Ir. Shou-En Zhu and Dr. Victor Calado.

The team subsequently performed measurements on the electrical properties of this cvd-graphene no one had been able to do before. They were the first to demonstrate ballistic transport in synthetic graphene.

“We could measure ballistic transport of the electrons over a micron distance”, says prof. Lieven Vandersypen, who is one of the co-authors. “That is really special. It demonstrates that cvd-graphene can be of very high quality.”

Victor Calado, Shou-En Zhu et., al. Ballistic transport in graphene grown by chemical vapor deposition, Applied Physics Letters, January 13 2014