Boron Nitride

Scientists from Manchester University, the Ulsan National Institute of Science & Technology and the Korea Institute of Science and Technology have developed a novel technology, which combines the fabrication procedures of planar and vertical heterostructures in order to assemble graphene-based single-electron transistors.

The schematic structure of the devices

In the study, it was demonstrated that high-quality graphene quantum dots (GQDs), regardless of whether they were ordered or randomly distributed, could be successfully synthesized in a matrix of monolayer hexagonal boron nitride (hBN). Here, the growth of GQDs within the layer of hBN was shown to be catalytically supported by the platinum (Pt) nanoparticles distributed in-between the hBN and supporting oxidised silicon (SiO₂) wafer, when the whole structure was treated by the heat in the methane gas (CH₄). It was also shown, that due to the same lattice structure (hexagonal) and small lattice mismatch (~1.5%) of graphene and hBN, graphene islands grow in the hBN with passivated edge states, thereby giving rise to the formation of defect-less quantum dots embedded in the hBN monolayer.

Graphene Flagship researchers at DTU, Denmark, solved the problem of graphene's accumulation of defects and impurities due to environmental exposure by protecting it with insulating layers of hexagonal boron nitride, another two-dimensional material with insulating properties.

Peter Bøggild, researcher at Graphene Flagship partner DTU and coauthor of the paper, explains that although 'graphene is a fantastic material that could play a crucial role in making new nano-sized electronics, it is still extremely difficult to control its electrical properties.' Since 2010, scientists at DTU have tried to tailor the electrical properties of graphene, by making a very fine pattern of holes, so that channels through which an electric power can flow freely are formed. 'Creating nanostructured graphene turned out to be amazingly difficult, since even small errors wash out all the properties we designed it to have,' comments Bøggild.