Researchers at the Massachusetts Institute of Technology and elsewhere are looking to make graphene using chemical vapor deposition (CVD), an established process that could be readily integrated into microchip fabrication. In CVD, volatile chemicals react and deposit themselves on a substrate as a thin coating. The M.I.T. process employs a simple, tube-shaped furnace containing nickel substrates, electrical engineer Jing Kong says. “At one end, we flow in hydrocarbon gas, which decomposes in the heat,” she explains. Carbon atoms then fall onto the nickel surface, which acts as a catalyst to help form the graphene films. The quality of the graphene, though, depends on the substrate—whether it consists of many nickel crystals or only one, Kong explains. Unfortunately, single-crystal nickel, the most desirable, is costly.
Graphene from CVD has led to one of the biggest achievements yet. A group led by Byung Hee Hong of Sungkyunkwan University in South Korea made high-quality films that the scientists stamped onto a clear, bendable polymer. The result was a transparent electrode. Improved versions could replace the more expensive transparent electrodes (typically made from indium titanium oxide) used in displays.
Ultimately, the graphene-making game may see more than one winner. Trinity College’s Coleman says that the solution-based exfoliation methods, which to date produce graphene up to several tens of microns wide, are probably best suited for “middle-size industrial quantities, whereas the Intels of the world will likely be more interested in growing huge areas of graphene using CVD-type processes,” which so far can make samples up to a few square centimeters. But perhaps best of all, none of the approaches seem to face insurmountable hurdles. As Rice’s Tour puts it: “I’ll bet that the problems will be solved within a year or two.”
Editor's Note: This story was originally printed with the title "Grinding Out Graphene"