The single-atom-thick layers of hexagonal boron nitride (h-BN), the material under intense study at Rice University's Department of Mechanical Engineering and Materials Science, are likely to find some macro applications as well. Researchers across a number of laboratories have announced a method of producing sheets of h-BN, which could turn out to be the turning point in the large scale adoption of this wonder material. [Song et al., Nano Lett., 2010, 10, 3209].
Graphene began the trend with its enhanced electronic properties, with new properties still being discovered today. Hexagonal boron nitride, on the other hand, is an insulator. Earlier this year, Rice postdoctoral researchers in Ajayan's group found a way to implant islands of h-BN into sheets of graphene, a unique way to exert a level of control over the sheets electronic character.
The team lead by primary author li Song has figured out how to deposit sheets of pure h-BN, which is naturally white in bulk form, anywhere from one to five atoms thick on a copper substrate. The material can then be transferred to other substrates.
They used a chemical vapour deposition technique to grow the h-BN sheets on a 5 by 5 cm copper backing at temperatures of up to 1000 degrees Celsius. The sheets could then be stripped from the copper and placed on a variety of substrates.
Song sees h-BN sheets finding wide use as a highly effective insulator in graphene based electronics. Song also mentioned it should also be possible to draw microscopic patterns of graphene and h-BN, which could be useful in creating nanoscale field-effect transistors, quantum capacitors or biosensors.
Strength tests using the tip of an atomic force microscope to push h-BN into holes in a silicon substrate showed it to be highly elastic and nearly as strong as graphene, the single-atom form of pure carbon.
Song said the size of h-BN sheets is limited only by the size of the copper foil and furnace used to grow it. The process should be adaptable to the same kind of roll-to-roll technique recently used to form 30 inch sheets of graphene.