Published on July 24th, 2011 | by Tina Casey1
Atomic-Level “Cowboy” Herds Graphene Grains into Shape
Graphene, the newly discovered material that is only one atom thick but two hundred times stronger than steel, could be put to infinite uses in the next generation of electronic devices, but getting graphene to behave is a little like herding cats…until now. A team of scientists at Oak Ridge National Laboratory has discovered that hydrogen can function like an atomic-scale cowboy, controlling the growth of graphene grains to form well defined, perfect hexagons.
Graphene was discovered just a few years ago, and initial attempts to produce it were somewhat primitive. Researchers literally pressed a piece of tape over a piece of graphite to detach the single sheet of carbon atoms that form graphene (graphite is basically a stack of graphene sheets). Emerging tactics include using water droplets to coax graphene into different shapes, and fabricating a coated paper and then chemically reducing it to produce uniform graphene sheets. The key sticking point is finding a method that works consistently and economically on a large, commercial scale.
More recently, researchers have begun to use vapor deposition to grow graphene on copper foil. The problem is, unlike natural graphene, the synthetic version consists of irregular, differently sized grains. The natural material has a distinctively uniform, chickenwire-like lattice structure that provides it with unique properties, including the ability to form nanoscale graphene bubbles.
The Oak Ridge Graphene Recipe
In the vapor deposition method, the substrate and the source of the carbon influence the shape and size of each graphene grain. The Oak Ridge researchers discovered a third variable in hydrogen, which previously had been thought to play a passive role in the process. Hydrogen helps to initiate the growth of the grains, and it also helps to eliminate weak bonds at the grain edges.
If the new method can be replicated on a mass scale, it would result in the introduction of a cheaper, lighter, stronger, and more functional material for use in semiconductors and hundreds if not thousands of electronic devices.
Read more about graphene:
- Graphene, the New “Miracle Material,” Can Be Made from Plain Sugar
- Graphene Gate Opens the Door to Smaller, Faster, Less Toxic Electronics
- The “Flat Stanley” Wonder Material Called Graphene Gets a New Sidekick: Graphane
Images: Cowboy by Sean MacEntee on flickr.com; Graphene grains courtesy of Oak Ridge National Laboratory.