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.

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.

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.

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.

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.