Zhu has demonstrated millimeter-sized graphene crystals made by chemical vapour deposition of methane on a copper sheet. He sends a low-pressure mix of hydrogen, methane and argon over a copper sheet at a temperature of 1,000 degree celsius. The copper acts as a catalyst in stripping the hydrogen from the methane, leaving pure carbon that sticks to the surface and perfectly aligns with other carbon atoms into this endless sheet of pure graphene.
Other parties need ten hours to produce graphene by deposition. Zhu, however, has brought back the production time to about one hour by splitting the quartz tube in which the deposition takes place from the oven that surrounds it. After deposition, he simply slides the furnace away to speed up cooling.
“Now a single piece of graphene costs about €1,000”, said Zhu. “We expect to reduce the price by a factor of thousand to about €1 per piece in a few years.”
Zhu demonstrated that millimeter-sized piece of graphene was, in fact, one single crystal by freely moving the electrons around in it. Together with his colleagues, he applied a perpendicular magnetic field to the graphene. The field pushed the free moving electrons into circular trajectories without any scattering. Thus he proved that the synthetic graphene was flawless.
SOURCE - Delta Magazine of Delft Technical University