Electronics - Page 3

Researchers at the University of Kansas’ Ultrafast Laser Lab have observed the ballistic movement of electrons in graphene in real time. 

Image credit: University of Kansas

“Generally, electron movement is interrupted by collisions with other particles in solids,” said lead author Ryan Scott, a doctoral student in KU’s Department of Physics & Astronomy. “This is similar to someone running in a ballroom full of dancers. These collisions are rather frequent — about 10 to 100 billion times per second. They slow down the electrons, cause energy loss and generate unwanted heat. Without collisions, an electron would move uninterrupted within a solid, similar to cars on a freeway or ballistic missiles through air. We refer to this as ‘ballistic transport.’”

Researchers from Helmholtz-Zentrum Dresden-Rossendorf, Universität Duisburg-Essen, CENTERA Laboratories, Indian Institute of Technology, University of Maryland and the U.S. Naval Research Laboratory have used graphene disks to demonstrate light-induced transient magnetic fields from a plasmonic circular current with extremely high efficiency. 

The effective magnetic field at the plasmon resonance frequency of the graphene disks (3.5 THz) is evidenced by a strong ( ~ 1°) ultrafast Faraday rotation ( ~ 20 ps). In accordance with reference measurements and simulations, the team estimated the strength of the induced magnetic field to be on the order of 0.7 T under a moderate pump fluence of about 440 nJ cm⁻².

Researchers at the National University of Singapore (NUS), University of Science and Technology of China and the National Institute for Materials Science in Japan have developed a way to induce and directly quantify spin splitting in two-dimensional materials.

Using this concept, they have experimentally achieved large tunability and a high degree of spin-polarization in graphene. This research achievement can potentially advance the field of two-dimensional (2D) spintronics, with applications for low-power electronics.

Researchers at Texas A&M University recently discovered that when charging a supercapacitor, it stores energy and responds by stretching and expanding. This insight could be help design new materials for flexible electronics or other devices that need to be both strong and store energy efficiently.

The team measured stresses that developed in graphene-based supercapacitor electrodes and correlated the stresses to how ions move in and out of the material. For example, when a capacitor is cycled, each electrode stores and releases ions that can cause it to swell and contract. According to the team, this repeated motion can cause the build-up of mechanical stresses, resulting in device failure. To combat this, the research looks to create an instrument that measures mechanical stresses and strains in energy storage materials as they charge and discharge.

Researchers at MIT, Harvard and Japan's National Institute for Materials Science have reported a surprising property in graphene: When stacked in five layers, in a rhombohedral pattern, graphene displays a rare, “multiferroic” state, in which the material exhibits both unconventional magnetism and an exotic type of electronic behavior, which the team has named "ferro-valleytricity".

“Graphene is a fascinating material,” said Long Ju, assistant professor of physics at MIT. “Every layer you add gives you essentially a new material. And now this is the first time we see ferro-valleytricity, and unconventional magnetism, in five layers of graphene. But we don’t see this property in one, two, three, or four layers”. The discovery could promote ultra-low-power, high-capacity data storage devices for classical and quantum computers.

Versarien has reported that its Spanish business has secured funding for a new project, in a boost to the group’s turnaround strategy. The Company said its majority-owned subsidiary, Gnanomat, has been awarded a grant of around €415,000 (around USD$445,660) by a government body.

Gnanomat will use the money to help develop and commercialize a new line of conductive inks based on Versarien's nanomaterials, for use in the production of electronic goods.

The MINIGRAPH project (Minimally Invasive Neuromodulation Implant and implantation procedure based on ground-breaking GRAPHene technology for treating brain disorders) aims to pave the way for a new generation of adaptive neuroelectronic therapies, resolving the most important limitations of current technology. The project revolves around the development of a new generation of graphene-based brain implants.

The project started in October 2022 and will go on for 36 months. It is a HORIZON-EIC project, with an estimated cost of €3,928,402.50. Among its members are ICN2, IMEC, Fraunhofer, INBRAIN Neuroelectronics, MSRL and more. Recently, Scientists from the Czech Advanced Technologies and Research Institute – CATRIN at Palacký University also announced that they will participate in the project.

Researchers from Seoul National University of Science and Technology (SeoulTech) and Kwangwoon University recently used a novel approach called UV-assisted atomic layer deposition (UV-ALD) to treat graphene electrodes. The choice of this technique resulted in the successful production of a high-performance graphene-dielectric interface. 

The research team became the first to apply UV-ALD to the deposition of dielectric films onto the surface of graphene. Atomic layer deposition (ALD) involves adding ultra-thin layers at the atomic scale to a substrate, and its significance has grown considerably as semiconductor components have shrunk in size. UV-ALD, which combines ultraviolet light with the deposition process, enables more dielectric film placement than traditional ALD. However, no one had explored the application of UV-ALD for 2D materials such as graphene.

Researchers from POLYMAT at the University of the Basque Country UPV/EHU, Max Planck Institute for Polymer Research and the University of Aveiro have reported an accelerated iterative approach enabling the synthesis of a series of length-controlled, ultralong atomically precise graphene nanoribbons (GNRs). The longest GNR displays a 920-atoms core with a 35.8-nm long (147 linearly fused rings) backbone that has been obtained in just three synthetic steps from building blocks of ∼2 nm in length. 

A Lego-like synthesis previously produced record-breaking nanoribbons of 30, then 53 fused rings. Now, a similar ‘accelerated’ modular methodology made a molecular nanoribbon that is triple the longest ever made – in just three simple steps. The resulting graphene nanoribbon is almost 36nm long, with its 147 linearly linked rings and a conjugated core of 920 atoms. The first experiments, although preliminary, envision applications in electronics and optoelectronics, thanks to fluorescence features that reportedly outperform state-of-the-art quantum dots.

Researchers from Portugal's Instituto de Engenharia de Sistemas e Computadores – Microsistemas e Nanotecnologias (INESC MN), Universidade de Lisboa and the UK's University of Exeter have developed an efficient flexible triboelectric textile by using printed graphene electrodes with polydimethylsiloxane (PDMS) and the textile itself as the triboelectric pair.

To achieve this, the team used a textile planarization technique with a polyurethane adhesive, along with three different deposition methods: graphene droplet films (GDF), graphene immersion films (GIF), and graphene spray films (GSF).