Adding depth to graphene

Ever since graphene was first discovered as a new state of carbon that does not exist in nature, plenty of new applications have been suggested for this new chemical wonder. Among them was the possibility of using a patch of graphene as a nano-scale transistor. Indeed, working graphene transistor prototypes have been demonstrated at labs around the world, including chip giants Intel and IBM.
So far though, all such efforts had proved impractical because the conductivity of graphene was too good as graphene is not in and of itself a semiconductor. The graphene was systematically letting through way too many electrons across the sheet to create an off-state for the transistor that could be reliably distinguished from the on-state.
However, the team of Dr Leonid Ponomarenko at Manchester University in the UK have just published a new study in which they suggest sandwiching an atom-thick layer of molybdenum disulfide between two layers of graphene. In this configuration, the electrons travel through the graphene sheet vertically instead of horizontally and the molybdenum disulfide acts as a dielectric, through which electrons can tunnel. By modulating the electric potential between the two layers of graphene, one can greatly enhance or diminish the probability of tunneling for the electrons, in a non-linear fashion as in tunneling transistors, which leads to two distinct on- and off-states.
As Dr Novoselov explains, "this opens a new dimension in graphene research."

Read news brief in New Scientist here and the reference for the Science paper: DOI: 10.1126/science. 1218461.