DNA template used to grow graphene circuitry

Ars Technica : Graphene consists of carbon atoms arranged in a symmetrical hexagonal sheet that is one atom thick. In sheet form it conducts electricity well, and in ribbons that are less than 10-nm across, it behaves as a semiconductor. Such ribbons are desirable for use in electrical circuitry, but are very difficult to create. A new technique, developed by Zhenan Bao of Stanford University and his colleagues, uses DNA as a template for growing graphene-like ribbons. Bao’s team chose to work with DNA because the molecule is relatively easy to manipulate and bonds with copper nitrate, a catalyst used to convert methane into graphene. The team laid strands of DNA, both individually and as overlapping crosses, on silicon wafers to create simple circuits. The wafers were then soaked in copper nitrate and heated in ovens filled with methane and hydrogen gas. A graphene-like material formed on the DNA template and then the DNA and catalyst evaporated away. The material is not pure graphene because 15% of the carbon is noncrystalline. Those areas behave as resistors when the strands are hooked to electrical sources. However, the researchers were still able to create successful circuits from the ribbons. Even before reducing the amount of nongraphene carbon formation, the new technique is a promising step in the development of useful graphene circuitry.