Researchers design a method for detecting individual impurities in graphene

A team of researchers from the University of Basel, the National Institute for Material Science in Tsukuba in Japan, Kanazawa University, Kwansei Gakuin University in Japan and Aalto University in Finland has succeeded in using atomic force microscopy to obtain images of individual impurity atoms in graphene ribbons. Thanks to the forces measured in the graphene's two-dimensional carbon lattice, they were able to identify boron and nitrogen for the first time.

Researchers design a method to detect individual impurities in graphene image Using the atomic force microscope's carbon monoxide functionalized tip (red/silver), the forces between the tip and the various atoms in the graphene ribbon can be measured

The team replaced particular carbon atoms in the hexagonal lattice with boron and nitrogen atoms using surface chemistry, by placing suitable organic precursor compounds on a gold surface. Under heat exposure up to 400°C, tiny graphene ribbons formed on the gold surface from the precursors, including impurity atoms at specific sites.

Graphene and hBN used to create unique 2D quantum bits

Two novel 2D materials, graphene and hexagonal boron nitride, and the tip of a scanning tunneling microscope – these were the ingredients used to create a novel kind of a so-called “quantum dot”. These extremely small nanostructures allow delicate control of individual electrons by fine-tuning their energy levels directly. Such devices can be key for modern quantum technologies.

Graphene and hBN 2D quantum bits image

The theoretical simulations for the new technology were performed at TU Wien. The experiment involved RWTH Aachen and the team around Nobel-prize laureates Andre Geim and Kostya Novoselov from Manchester who prepared the samples.

U.S collaboration grows large single-crystal graphene that could advance graphene research and commercialization

A team led by the Department of Energy’s Oak Ridge National Laboratory, that also included scientists from University of Tennessee, Rice University and New Mexico State University, has developed a new method to produce large, monolayer single-crystal-like graphene films more than a foot long. The novel technique may open new opportunities for producing high-quality graphene of unlimited size and in a way that is suitable for roll-to-roll production.

Method to grow large single-crystal graphene could advance scalable 2D materials image

The ORNL team used a CVD method — but with a twist. They explained in this work how localized control of the CVD process allows evolutionary, or self-selecting, growth under optimal conditions, yielding a large, single-crystal-like sheet of graphene. “Large single crystals are more mechanically robust and may have higher conductivity,” ORNL lead coauthor Ivan Vlassiouk said. “This is because weaknesses arising from interconnections between individual domains in polycrystalline graphene are eliminated”. “Our method could be the key not only to improving large-scale production of single-crystal graphene but to other 2D materials as well, which is necessary for their large-scale applications,” he added.

Graphene can be tuned to behave as both an insulator and a superconductor

Researchers at MIT and Harvard University have found that graphene can be tuned to behave at two electrical extremes: as an insulator, in which electrons are completely blocked from flowing; and as a superconductor, in which electrical current can stream through without resistance.

MIT and Harvard team create graphene ''superlattice'' that can be superconductive and insulating image

Researchers in the past, including this team, have been able to synthesize graphene superconductors by placing the material in contact with other superconducting metals — an arrangement that allows graphene to inherit some superconducting behaviors. In this new work, the team found a way to make graphene superconduct on its own, demonstrating that superconductivity can be an intrinsic quality in the purely carbon-based material.

Graphene and hBN join to create unique ‘petri-dish’

Researchers at The University of Manchester and the NGI have shown how graphene and boron nitride can be used for observing nanomaterials in liquids, by creating a ‘petri-dish’ of sorts.

Graphene and hBN ''petri-dishes'' image

Scanning / transmission electron microscopy (S/TEM) is one of only few techniques that allows imaging and analysis of individual atoms. However, the S/TEM instrument requires a high vacuum to protect the electron source and to prevent electron scattering from molecular interactions. Several studies have previously revealed that the structure of functional materials at room temperature in a vacuum can significantly different from that in their normal liquid environment. So, it is important to be able to study the structure at the required state.

XFNANO: Graphene and graphene-like materials since 2009XFNANO: Graphene and graphene-like materials since 2009