Researchers manipulate the width of GNRs to create quantum chains that could be used for nano-transistors and quantum computing

Researchers at EMPA (Swiss Federal Laboratories for Materials Science and Technology), along with colleagues from the Max Planck Institute for Polymer Research in Mainz and other partners, have succeeded in precisely controlling the properties of graphene nano-ribbons (GNRs) by specifically varying their shape. This can be used to generate specific local quantum states, and could in the future be used for precise nano-transistors or possibly even quantum computing.

Researchers manipulate the width of GNRs to create quantum chains that could be used for nano-transistors and quantum computing image

The team has shown that if the width of a narrow graphene nano-ribbon changes, in this case from seven to nine atoms, a special zone is created at the transition: because the electronic properties of the two areas differ in a special, topological way, a "protected" and thus very robust new quantum state is created in the transition zone. This local electronic quantum state can be used as a basic component to produce tailor-made semiconductors, metals or insulators - and perhaps even as a component in quantum computers.

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 nanoribbons on a gold surface may open the door to improved electronics and future spintronics applications

A research team at the U.S. Department of Energy’s (DOE) Argonne National Laboratory has placed armchair-edge graphene nanoribbons (AGNRs) on a gold surface. Since AGNRs become semiconductors at certain widths, this structure may offer advantages in speed, heat dissipation and power consumption in electronic devices and create new research paths in spintronics.

The goal was to use AGNRs to block magnetic interactions on a metal. The team focused on how the AGNRs affect these interactions in a molecule tightly adhered to gold using the phenomenon of Kondo resonance — a well-defined, temperature-dependent effect between a single magnetic atom or molecule and a metal’s free electrons. For this purpose, the team relied on a low-temperature scanning tunneling microscopy tool at Argonne’s Center for Nanoscale Materials.

Graphene nanoribbons contact the molecular world

A collaboration between Spanish research institutes—led by the nanoGUNE Cooperative Research Center (CIC)—has achieved a breakthrough in so-called molecular electronics by devising a way to connect magnetic porphyrin molecules to graphene nanoribbons. These connections may be an example of how graphene could enable the potential of molecular electronics.

magnetic porphyrin molecule is connected to a GNR image

Porphyrin is an important molecule that is responsible for making photosynthesis possible in plants and transporting oxygen in the blood. Recently, researchers have been experimenting with "magnetic porphyrins" and discovered that they can form the basis of spintronic devices. Spintronics involves manipulating the spin of electrons and it is this spin that is responsible for magnetism: When a majority of electrons in a material have their spins pointing in the same direction, the material is magnetized. If you can move all the spins up or down and can read that direction, you can create the foundation of the “0” and “1” of digital logic.

Researchers observe high intensity light emission from individual graphene nanoribbons

Researchers led by the CNR-Nanoscience Institute in Modena, Italy, and the University of Strasbourg in France, have experimentally observed light emission from individual graphene nanoribbons for the first time. They demonstrated that 7-atom-wide nanoribbons emit light at a high intensity that is comparable to bright light-emitting devices made from carbon nanotubes, and that the color can be tuned by adjusting the voltage. These findings may open the door to the development of bright graphene-based light sources.

Light emission from individual graphene nanoribbons image

Experimentally, there have been only a few demonstrations of light emission from graphene nanoribbons, and these have been limited to ensembles of nanoribbons and revealed only weak light emission. So the results of the new study, which show a much brighter light emitted by individual graphene nanoribbons compared to ensembles, hint at the exciting potential of graphene's optical properties.