Graphene, the thinnest and strongest substance on Earth, is the “sexiest” material around — and, it conducts electricity at least as well as copper. This carbon-based super-material is only one atom thick, and — it will revolutionize the world as we know it. Graphene will eventually be used to create skintight suits for astronauts, condoms, electric sensors and circuits, and it will enable the Internet to go faster than ever before.
Graphene is also nontoxic, inexpensive, completely flexible, and transparent. In theory, this makes graphene perfect for being used to conduct electricity in solar cells, with no reduction in the flow of incoming light from the sun.
One problem that scientists faced with growing graphene was that to create the material, a very high temperature was required. To create graphene, the scientists had to find a substrate which would be able to withstand such high temperatures.
What sort of substrate has been proposed to grow graphene?
Researchers at the National Institute of Standards and Technology (NIST) in Boulder, Colorado, have come up with a possible ideal sort of substrate to grow graphene. They have hit upon a recipe for a potential substrate by using copper, a thin film of it, one which has very large crystalline grains. The findings of the research team appear in the journal AIP Advances.
The researchers found that the key to creating the perfect substrate for graphene was that the copper’s grain size had to be massive — the large size of the copper grains helped them to withstand the high temperatures required to grow graphene.
Most copper films before this discovery was made were unable to withstand the high temperatures needed, thus “preventing wafer-scale production of graphene devices,” according to NIST researcher Max Keller.
How did the researchers create the massive grain size in the copper substrate?
The copper substrate needed to grow graphene had to have massive grain sizes in it to withstand the high temperatures needed to grow graphene. The copper grain sizes needed to be around 10,000 times more massive than normal copper. Creating this type of copper, the researchers discovered, was a two-step process.
The researchers used a sapphire wafer at just slightly above room temperature. The second step was that the researchers placed the copper onto the wafer, then annealed (heat-treated) the film close to the copper’s melting point. After that, to prove that the copper film with massive grains would make a great substrate, the researchers then grew graphene grains on the new copper substrate.
The study is titled “Giant secondary grain growth in Cu films on sapphire.” The National Graphene Institute in Manchester has already used the new material, graphene, to create — believe it or not — safer condoms. They are safer and more reliable than latex ones.
Recently, the Bill & Melinda Gates Foundation awarded the researchers $100,000 to pursue their research.
Graphene holds enormous promise and potential. The thinness of it, and other qualities such as its being transparent, flexible, a great conductor of electricity, and relatively cheap, could very soon lead to this material revolutionizing technology and improving many of the products we use on a daily basis.
Written by: Douglas Cobb