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Scientists create fully electronic 2-dimensional spin transistors

Posted By Graphene Council, The Graphene Council, Tuesday, October 15, 2019
Updated: Tuesday, October 15, 2019

Physicists from the University of Groningen constructed a two-dimensional spin transistor, in which spin currents were generated by an electric current through graphene. A monolayer of a transition metal dichalcogenide (TMD) was placed on top of graphene to induce charge-to-spin conversion in the graphene. This experimental observation was described in the issue of the journal Nano Letters published on 11 September 2019.

Spintronics is an attractive alternative way of creating low-power electronic devices. It is not based on a charge current but on a current of electron spins. Spin is a quantum mechanical property of an electron, a magnetic moment that could be used to transfer or store information.

Heterostructure
Graphene, a 2D form of carbon, is an excellent spin transporter. However, in order to create or manipulate spins, interaction of its electrons with the atomic nuclei is needed: spin-orbit coupling. This interaction is very weak in carbon, making it difficult to generate or manipulate spin currents in graphene. However, it has been shown that spin-orbit coupling in graphene will increase when a monolayer of a material with heavier atoms (such as a TMD) is placed on top, creating a Van der Waals heterostructure.

In the Physics of Nanodevices group, led by Professor Bart van Wees at the University of Groningen, Ph.D. student Talieh Ghiasi and postdoctoral researcher Alexey Kaverzin created such a heterostructure. Using gold electrodes, they were able to send a pure charge current through the graphene and generate a spin current, referred to as the Rashba-Edelstein effect. This happens due to the interaction with the heavy atoms of the TMD monolayer (in this case, tungsten disulfide). This well-known effect was observed for the first time in graphene that was in proximity to other 2D materials.

Symmetries

'The charge current induces a spin current in the graphene, which we could measure with spin-selective ferromagnetic cobalt electrodes,' says Ghiasi. This charge-to-spin conversion makes it possible to build all-electrical spin circuits with graphene. Previously, the spins had to be injected through a ferromagnet. 'We have also shown that the efficiency of the generation of the spin accumulation can be tuned by the application of an electric field,' adds Ghiasi. This means that they have built a spin transistor in which the spin current can be switched on and off.

The Rashba-Edelstein effect is not the only effect that produces a spin current. The study shows that the Spin-Hall effect does the same, but that these spins are oriented differently. 'When we apply a magnetic field, we make the spins rotate in the field. Different symmetries of the spin signals generated by the two effects in interaction with the magnetic field help us to disentangle the contribution of each effect in one system,' explains Ghiasi. It was also the first time that both types of charge-to-spin conversion mechanisms were observed in the same system. 'This will help us to gain more fundamental insights into the nature of spin-orbit coupling in these heterostructures.'

Graphene Flagship

Apart from the fundamental insights that the study can provide, building an all-electrical 2D spin transistor (without ferromagnets) has considerable significance for spintronic applications, which is also a goal of the EU Graphene Flagship. 'This is especially true because we were able to see the effect at room temperature. The spin signal decreased with increasing temperature but was still very much present under ambient conditions.'

Tags:  2D materials  Bart van Wees  Graphene  Graphene Flagship  Talieh Ghiasi  transistor  University of Groningen 

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Thomas Skordas: "Graphene is on the way to changing our lives"

Posted By Graphene Council, The Graphene Council, Wednesday, October 2, 2019
Thomas Skordas, Director for Digital Excellence and Science Infrastructure, takes a look at the latest developments in graphene research on the occasion of Graphene Week 2019 – Europe's leading graphene conference, which brings together the latest innovations, leading-edge technology and research on graphene and other layered materials.

Graphene Week was a chance to hear about recent scientific discoveries and technological advances in graphene, one of the key technology areas in Europe today. The great strength of the Graphene Flagship is that it provides a nurturing environment for top scientists, researchers and industry to discover new uses for this fascinating material, which consists of a single layer of carbon atoms.

This year alone, the Flagship has scored some significant achievements. For example, it has used graphene to increase the lifetime of Perovskite solar cells, the most efficient way of converting sunlight to energy in existence, when facing conditions such as heat and moisture. Once they are commercially viable, they could be a game changer for the clean energy transition. Flagship researchers have also built silicon-graphene coin cell batteries, of which a high proportion of the components can be recycled. This patented technology forms the basis of the spin-off Bedimensional, which received a private investment of €18 million in 2018, and test production is expected to start in the coming months.

Graphene has the potential to change our lives, and we are witnessing more and more graphene product launches and spin-offs. The Flagship also regularly presents new demonstrators at events, such as the mobile phone-related technology shown at Mobile World Congress: this video shows what they presented. We are also looking forward to the publication in the next few weeks of a 400-page open-access book, the work of 70 co-authors, with information on how to produce graphene and up to 5000 other layered materials. It will be a “bible” for students and industrial manufacturers interested in the fabrication processes of these materials. We have come a long way: merely fifteen years ago, graphene was isolated for the first time ever, in pioneering experiments using pieces of Scotch tape, but today the methods for synthesising thousands of similar materials are available to anyone in the world.

Tags:  Batteries  Digital Excellence and Science Infrastructure  Graphene  Graphene Flagship  Thomas Skordas 

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Graphene is wonderful – The Graphene Flagship project presents innovations in Brussels

Posted By Graphene Council, The Graphene Council, Thursday, September 26, 2019
European Commission funded research project, the Graphene Flagship, will demonstrate a selection of the project’s most exciting innovations at the Science is Wonderful exhibition in Brussels, Belgium, on 25 and 26 September 2019. The free exhibition, held at Tour & Taxis, a redeveloped industrial space in Brussels, is part of the European Research and Innovation Days and aims to bring a world of science and technology to the general public.

Demonstrations from the Graphene Flagship include technology that has been developed for human health and wellbeing. For example, a graphene-based brain implant that could be used to provide information on the onset of seizures. The new technology, which has been developed by Graphene Flagship partners the Microelectronic Institute of Barcelona (IMB-CNM, CSIC), the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and ICFO, demonstrates a major step in understanding the functions of the human brain.

The exhibition will also showcase examples of graphene dispersions and graphite electrodes manufactured by Graphene Flagship partner Talga. As a high-tech materials company and a leader in bulk graphene and graphite supply, Talga will demonstrate how graphene can easily be exfoliated from graphite, illustrating the journey from material exfoliation, right through to commercialisation.

Other demonstrations at Science is Wonderful include a newly developed virtual reality (VR) system which can be used to construct, manipulate and build graphene and other layered material structures. Developed by Graphene Flagship partner the Technical University of Denmark (DTU), the VR system demonstrates clearly how graphene can be modified and manipulated, with the ability to edit molecules and perform calculations on their electronic properties in real-time.

The VR system gives students and other citizens an unforgettable, low-barrier to entry for the complex machinery of atomic-scale materials and technology. However, it can also provide even experienced researchers with a unique sandbox for scientific problem solving, quantitative analysis, idea generation and discovery.

“The Graphene Flagship’s presence at Science is Wonderful will bolster its efforts to promote the use of graphene in commercial products,” explained Jari Kinaret, director of the Graphene Flagship. “During the first five years of our ambitious Graphene Flagship project, we managed to bring together academic researchers and industrial business leaders to create and commercialise technologies that are already improving European society — the demonstrations at Science is Wonderful will showcase some beautiful examples.”

Tags:  CSIC  Graphene  Graphene Flagship  Healthcare  ICFO  ICN2  Jari Kinaret  Technical University of Denmark 

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Join the Graphene Flagship Core 3 Project

Posted By Graphene Council, The Graphene Council, Friday, May 10, 2019



The Graphene Flagship is looking for new partners to bring specific industrial and technology transfer competences or capabilities that complement the present consortium in the next core project. 

We are seeking partners with the following expertise:

  • MRAM tools developer to leverage solutions for GRM-spintronic stacks
  • Exposure and risk assessment of GRMs for occupational health
  • Clinical translation of GRM-based therapeutic medical devices for the central nervous system
  • Component manufacturer for GRM-based networking devices and interconnects 
  • Developer of GRM-based laser systems and instrumentation for coherent Raman imaging
  • Manufacturing and modification of GRM-based fibres, yarns and textiles
  • Automotive company with expertise in development of fuel cells for cars
  • Industrial GRM-based supercapacitors manufacturer
  • Manufacturer of GRM-based anticorrosion coatings
  • Developer of GRM-based pressure sensors for health monitoring in automotive applications
  • Manufacturer to deliver a ready-to-reach-the-market sports car with enhanced functionalities based on GRM/Carbon Fibre Reinforced Polymer composites
  • GRM-based composites manufacturer
  • Preparation of large GRM-based multifunctional pipes by filament winding
  • Formulation of low viscosity epoxy resins incorporating GRMs for aerostructures manufactured by infusion technologies


The selected new partners will be incorporated in the scientific and technological Work Packages of the third Core Project under the Horizon 2020 phase of the Graphene Flagship that will run during 1 April 2020 – 31 March 2023.

The addition of new partners to the Graphene Flagship consortium is subject to the approval of the required contract amendment by the Graphene Flagship General Assembly and, at a later stage, the European Commission.

Tags:  Graphene  Graphene Flagship 

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Exploring the Graphene Flagship through the eyes of a Nobel Prize winner

Posted By Graphene Council, The Graphene Council, Tuesday, April 2, 2019
Updated: Tuesday, March 19, 2019

Talking with SciTech Europa, Professor Novoselov, who was co-awarded the 2010 Nobel Prize in Physics, for the discovery and isolation of a single atomic layer of carbon for the first time, explores the research into Graphene Flagship and other 2D materials.

At the University of Manchester, UK, in 2004, Professor Sir Kostya Novoselov, along with his colleague Professor Sir Andre Geim, discovered and isolated a single atomic layer of carbon for the first time. The pair received the Nobel Prize in Physics in 2010 in recognition of their breakthrough.

On 28 January 2013, the European Commission announced that, out of the six pilot preparatory actions put forwards for the Future and Emerging Technology (FET) Flagships competition, the Graphene Flagship, along with the Human Brain Project, had been selected to receive €1bn in funding over the course of a decade, tasking it with bringing together academic and industrial researchers to take graphene from the realm of academic laboratories into European society, thereby generating economic growth, new jobs, and new opportunities.

In February, SciTech Europa attended the Mobile World Congress in Barcelona, Spain. This event is the world’s largest exhibition for the mobile industry, and where, for the fourth consecutive year, the Graphene Flagship hosted its Graphene Pavilion – this year showcasing over 20 different graphene-based working prototypes and devices that will transform future telecommunications.

At the pavilion, SEQ met with Professor Novoselov to discuss research into graphene and other two dimensional materials, as well as how the Flagship is working to bolster both fundamental research and applications stemming from these advanced materials.

Q. What do you think have been the biggest, and latest, developments in graphene (and other 2D materials) research?

There has been a lot of progress in recent years and, indeed, we are no longer talking only about graphene, but also about many other two dimensional materials as well.

First of all – new applications of graphene is one example of recent developments – we see new applications emerging on an almost monthly basis. Second, there is still a lot of progress being made in fundamental research on graphene and 2D materials. And those fundamental results are being implemented in applications.

In terms of other new 2D materials, there is a lot of activity on ferromagnetic materials.

Q. What potential is there now to move graphene forwards, and how would you describe the role of the Flagship in this?

The basic technology is in place, and so what is important now is for entrepreneurs and SMEs to convert those developments into commercial applications, and, indeed, we need to help them to do so.

The Flagship, of course, has now reached the half way stage, and we therefore need to carefully balance the amount of effort we place on applications with the effort we place on the development of fundamental science, which remains crucial.

Nevertheless, we also need to ensure we are helping companies and industry to introduce this material into real products, and that is actually much more difficult, not least because of the fact that this has not been done at this scale before, and so nobody knows how to do it yet.

Q. Are you able to utilise EU instruments to help fund commercialisation activities?

It is not necessarily funding that is a problem in in Europe; the challenge comes more in the form of bringing together scientists, entrepreneurs, and funders in the same room, and it is still not clear how to achieve that. There is thus the argument that we need to work more closely with entrepreneurs and we need to grow those entrepreneurs who are working on advanced materials because this is a much more challenging area than, say, ‘.com’ applications.

Q. What do you feel are the biggest barriers here?

It is perhaps the mentality that exists around risk taking that needs to change. Bringing together entrepreneurs, scientists, the technology and the money around the same table is a challenge and, as I have mentioned, it needs to be understood that bringing new materials, especially nanomaterials, to market is much more challenging than it is to bring, for example, new software to consumers. And, of course, the level of required investment is also much larger. Whether we have enough people in Europe who are ready to take this risk is a good question.

Q. Would you say that Europe is too risk averse when it comes to this type of investment in comparison to, for instance, the USA?

Perhaps; there is certainly a sense that Europe needs to work much harder than the USA or South-East Asia. And the reason for that is not only a lack of those willing to take enhanced risks, but also the level and mobility of the available money and, indeed, how soon financiers expect a return on their investment.

Q. Could 2D materials research spark a ‘revolution’ in real world applications?

I am not sure that we will see a ‘revolution’; the growth in real world applications utilising graphene is, and will continue to be, a gradual introduction. That is not to say, however, that this gradual process won’t speed up a little over time. And it is great to see that, when it comes to graphene, this introduction, although gradual, is already happening much faster than with any other advanced material that we have seen before. The purpose of the Flagship is to help speed up this process.

The Flagship is now investing in research into the safety of graphene. How important is that?
This is an example of the sort of issue where the Flagship should take the initiative, because it is not only about graphene; we need to realise that many new nanomaterials are going to play an increasing role in the everyday lives of people, and we need to be prepared for that.

There are a great many regulations which have to be passed when bringing such advanced materials to market, including health and safety and toxicology regulations, and very often these are not very well defined because, quite simply, we have never been in this situation before. It can also be quite expensive to run the necessary projects to investigate things like toxicology, and so it is important for projects like the Flagship to take the initiative and help businesses to overcome these barriers.

Q. Where are your own research interests going to lie, moving forwards?

I do indeed conduct my own research, and within that graphene is not the largest part. I go beyond graphene and work on many other 2D materials and heterostructures, but it is nevertheless exciting to remember that it was graphene that made all the other materials possible as we work on those heterostructures towards new discoveries.

Tags:  2D materials  Graphene  Graphene Flagship  Kostya Novoselov  University of Manchester 

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How is graphene holding up at Warsaw University of Technology?

Posted By Graphene Council, The Graphene Council, Tuesday, March 26, 2019
Updated: Tuesday, March 26, 2019

Warsaw University of Technology (“WUT”), for more than 10 years, has been involved in extensive research into graphene, its applications and production techniques, in both domestic and international projects (it boasts more than 250 scientific publications in international journals and several patents). As the only institution of higher education in Poland, it is a member of the Graphene Flagship programme, the EU’s biggest ever research initiative. The project work is carried out among others in the cutting-edge Center for Advanced Materials and Technologies (CEZAMAT) and is scheduled to continue until at least March 2022.

The University cooperates with scientific and industrial partners from Sweden, the United Kingdom, Austria and China to further advance the technology of epitaxial graphene on silicon carbide for applications such as 5G technologies. WUT’s PhD students engage in joint research at scientific institutions across Europe, including Cambridge and Madrid.

WUT pursues a number of high-end national projects that focus on research into graphene and new two-dimensional materials: Team-Tech (Foundation for Polish Science), Lider and TechmatStrateg (National Centre for Research and Development), Sonata and Preludium (National Science Centre), Diamentowy Grant (Ministry of Science and Higher Education).

The University has established the Graphene Laboratory (Faculty of Chemistry and Process Engineering) dedicated to the carbon nanomaterial production, characterization and exploration of new applications, e.g. hybrid fluorescent materials or infrared radiation absorbers or even some unusual solutions such as the development of new polyester gelcoats to be used in the construction of new generation yachts, Delphia Nano Solution. It is also a promoter of spin-offs aimed at the transfer of graphene technologies and applications to industry and putting them to use for commercial production. Moreover, numerous businesses collaborate with Warsaw University of Technology in application research under joint projects and bilateral agreements.

The work on graphene at Warsaw University of Technology covers two types of this material: graphene flakes and epitaxial graphene (film). “The University has several processing lines producing graphene flakes with the use of both chemical methods of oxidation and reduction of graphene oxide and the so-called liquid-phase direct exfoliation method. Last year, a new method was launched for the production of graphene flakes which is cheap, green and easily scalable for industry. WUT is now in the process of patenting this new technology,” says Prof. Mariusz Zdrojek, head of the graphene research group at  WUT’s Faculty of Physics.

The University has also launched an epitaxial graphene growth (on copper foil) for the purpose of its own application research. Moreover, it has developed and launched the growth technique of new two-dimensional materials in the graphene family, MXenes. The synthesis of other two-dimensional materials, i.e. molybdenum disulfide (MoS2), using the epitaxial growth method has also been elaborated.

Some of the more exciting graphene applications developed by the Warsaw University of Technology in collaboration with the Polish industry include:

- New generation ultrafast infrared photodetector created in 2015 under the Graf-Tech project. The device, in which graphene plays a key role, is in the pre-implementation phase (Faculty of Physics);

- Electronic nanodevices to be used in high-frequency electronics (for fast detectors, sensors or diodes), a product of the Lider project. Currently, work is underway on the patent application (Faculty of Physics);

- New nanocomposites for electromagnetic radiation protection for cybersecurity, electronics, aerospace and 5G technology. The patent application is pending with the European Patent Office (Faculty of Physics);

- Graphene thermal pastes for electronics as novel materials for heat transfer. Conductive graphene inks and pastes suitable for multi-surface printing technologies (e.g. clothes or banknote printing), where they act as transparent electrodes. Patented technology (Faculty of Mechatronics);

- Membrane technologies for mobile drinking water treatment plants, where use of graphene has improved selectivity. (Faculty of - Material Science and Engineering; Faculty of Chemical and Process Engineering);

- Graphene as an anti-corrosion coating, a product of the GrafTech project as part of the joint effort with a research partner (Faculty of Physics);

- other, i.e. flexible displays, pressure sensors, glucose sensors or amino acid biosensors.

For the past few years WUT’s researchers have been also conducting research into the application of other 2D materials. This  has resulted in creation of the materials’ potential new applications eg in the production of composites for the space and aerospace industries or as an innovative platform for drug delivery, new optoelectronic nanodevices or devices for terahertz electronics applications.

With the appropriate know-how, materials and infrastructure and access to the country’s best specialists,  Warsaw University of Technology remains at the leading edge of the development of technologies and applications for other two-dimensional materials, considered to be of strategic importance to advanced industry sectors.

Tags:  2D materials  Graphene  Graphene Flagship  Mariusz Zdrojek  Warsaw University of Technology 

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