New graphene nanoribbons could enable smaller electronic devices

A new collaborative study has reported a 17-carbon wide graphene nanoribbon and found that it has the tiniest bandgap observed so far among familiar graphene nanoribbons prepared through a bottom-up approach.

17-carbon wide graphene nanoribbons to pave the way for new GNR-based electronic devices image(a) Bottom-up synthesis scheme of 17-AGNR on Au(111), (b) high-resolution STM image, and (c) nc-AFM image of 17-AGNR. Image Credit: Junichi Yamaguchi, Yasunobu Sugimoto, Shintaro Sato, Hiroko Yamada.

The study is part of a project of CREST, JST Japan including Nara Institute of Science and Technology (NAIST), the University of Tokyo, Fujitsu Laboratories and Fujitsu.

Read the full story Posted: Jul 06,2020

Researchers manage to grow GNRs directly on top of silicon wafers

Scientist from the University of Wisconsin-Madison are working towards making more powerful computers a reality. To that end, they have devised a method to grow tiny ribbons of graphene directly on top of silicon wafers. Graphene ribbons have a special advantage over graphene sheets - they become excellent semiconductors.

Graphene ribbons grown on silicon achieved by U of WM team imageGraphene nanoribbons on silicon wafers could help lead the way toward super fast computer chips. Image courtesy of Mike Arnold

Compared to current technology, this could enable faster, low power devices, says Vivek Saraswat, a PhD student in materials science and engineering at UW-Madison. It could help you pack in more transistors onto chips and continue Moore’s law into the future. The advance could enable graphene-based integrated circuits, with much improved performance over today’s silicon chips.

Read the full story Posted: Sep 05,2019

Graphene ribbons could enable new designs for optical quantum computers

Scientists from the University of Vienna and the Institute of Photonic Sciences in Barcelona have shown that tailored graphene structures enable single photons to interact with each other, which could lead to new designs for optical quantum computers.

Photons barely interact with the environment, making them a leading candidate for storing and transmitting quantum information. However, this feature also makes it especially difficult to manipulate information that is encoded in photons. In order to build a photonic quantum computer, one photon must change the state of a second. Such a device is called a quantum logic gate, and millions of logic gates will be needed to build a quantum computer. One way to achieve this is to use a so-called 'nonlinear material' wherein two photons interact within the material. Unfortunately, standard nonlinear materials are far too inefficient to build a quantum logic gate.

Read the full story Posted: May 07,2019

Researchers make strides in achieving large scale production of graphene nanoribbons for electronics

Researchers have fully characterized graphene nanoribbons (GNRs) with a clear route towards upscaling the production. Two-dimensional sheets of graphene in the form of ribbons a few tens of nanometers across have unique properties that are highly interesting for use in future electronics.

Researchers make strides in achieving large scale production of graphene nanoribbons for electronics image

The nanoribbons were grown on a template made of silicon carbide under well controlled conditions and thoroughly characterized by a research team from MAX IV Laboratory, Techniche Universität Chemnitz, Leibniz Universität Hannover, and Linköping University. The template has ridges running in two different crystallographic directions to let both the armchair and zig-zag varieties of graphene nanoribbons form. The result is a predictable growth of high-quality graphene nanoribbons which have a homogeneity over a millimeter scale and a well-controlled edge structure.

Read the full story Posted: Jan 23,2019

Pristine graphene could lead to improved solar cells and photodetectors

An international research team, co-led by researchers at the University of California, Riverside, which also included researchers at MIT, Nanyang Technological University, Singapore; Institute of High Performance Computing, Singapore; UC Berkeley; and National Institute for Materials Science, Japan, has found a new mechanism for highly-efficient charge and energy flow in graphene, opening the door to new types of light-harvesting devices.

The researchers made pristine graphene into different geometric shapes, connecting narrow ribbons and crosses to wide open rectangular regions. They found that when light illuminated constricted areas, such as the region where a narrow ribbon connected two wide regions, a large light-induced current, or photocurrent, was detected.

Read the full story Posted: Dec 18,2018

UCSB team designs CMOS-compatible graphene interconnects

Researchers from the University of California, Santa Barbara, will be presenting a paper focused on CMOS-compatible graphene interconnects next month at the world-renowned semiconductor-technology conference - the IEEE International Electron Devices Meeting (Dec. 1-5 in San Francisco).

The team has shown that integrating graphene into the interconnect scheme holds the promise of increasing performance and limiting power consumption in next-generation CMOS ICs, as graphene offers high conductivity and is not prone to electromigration.

Read the full story Posted: Nov 13,2018

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.

Read the full story Posted: Aug 12,2018

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.

Read the full story Posted: Apr 15,2018

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.

Read the full story Posted: Feb 25,2018

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.

Read the full story Posted: Feb 18,2018