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Creating 2D heterostructures for future electronics

Posted By Graphene Council, The Graphene Council, Thursday, November 7, 2019
Updated: Thursday, November 7, 2019
While many nanomaterials exhibit promising electronic properties, scientists and engineers are still working to best integrate these materials together to eventually create semiconductors and circuits with them.

Northwestern Engineering researchers have created two-dimensional (2D) heterostructures from two of these materials, graphene and borophene, taking an important step toward creating intergrated circuits from these nanomaterials.

"If you were to crack open an integrated circuit inside a smartphone, you'd see many different materials integrated together," said Mark Hersam, Walter P. Murphy Professor of Materials Science and Engineering, who led the research. "However, we've reached the limits of many of those traditional materials. By integrating nanomaterials like borophene and graphene together, we are opening up new possibilities in nanoelectronics."

Supported by the Office for Naval Research and the National Science Foundation, the results were published October 11 in the journal Science Advances. In addition to Hersam, applied physics PhD student Xiaolong Liu co-authored this work.

Creating a new kind of heterostructure

Any integrated circuit contains many materials that perform different functions, like conducting electricity or keeping components electrically isolated. But while transistors within circuits have become smaller and smaller -- thanks to advances in materials and manufacturing -- they are close to reaching the limit of how small they can get.

Ultrathin 2D materials like graphene have the potential to bypass that problem, but integrating 2D materials together is difficult. These materials are only one atom thick, so if the two materials' atoms do not line up perfectly, the integration is unlikely to be successful. Unfortunately, most 2D materials do not match up at the atomic scale, presenting challenges for 2D integrated circuits.

Borophene, the 2D version of boron that Hersam and coworkers first synthesized in 2015, is polymorphic, meaning it can take on many different structures and adapt itself to its environment. That makes it an ideal candidate to combine with other 2D materials, like graphene.

To test whether it was possible to integrate the two materials into a single heterostructure, Hersam's lab grew both graphene and borophene on the same substrate. They grew the graphene first, since it grows at a higher temperature, then deposited boron on the same substrate and let it grow in regions where there was no graphene. This process resulted in lateral interfaces where, because of borophene's accommodating nature, the two materials stitched together at the atomic scale.

Measuring electronic transitions

The lab characterized the 2D heterostructure using a scanning tunneling microscope and found that the electronic transition across the interface was exceptionally abrupt -- which means it could be ideal for creating tiny electronic devices.

"These results suggest that we can create ultrahigh density devices down the road," Hersam said. Ultimately, Hersam hopes to achieve increasingly complex 2D structures that lead to novel electronic devices and circuits. He and his team are working on creating additional heterostructures with borophene, combining it with an increasing number of the hundreds of known 2D materials.

"In the last 20 years, new materials have enabled miniaturization and correspondingly improved performance in transistor technology," he said. "Two-dimensional materials have the potential to make the next leap."

Tags:  2D materials  Graphene  Mark Hersam  nanoelectronics  nanomaterials  Northwestern University  Xiaolong Liu 

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Colloids funds graphene nanocomposites collaborative Ph.D research project with The University of Manchester

Posted By Graphene Council, The Graphene Council, Thursday, October 17, 2019
Updated: Thursday, October 17, 2019
Colloids Group, a leading manufacturer of innovative masterbatches, compounds, and performance enhancing additives, is funding a joint collaborative Ph.D. research project with the Graphene Engineering Innovation Centre (GEIC) at The University of Manchester. The centre specialises in the rapid development and scale up of graphene and other 2D materials applications and focuses on several application areas to rapidly accelerate the development and commercialisation of new graphene technologies.The GEIC is an industry-led innovation centre, designed to work in collaboration with industry partners to create, test and optimise new concepts for delivery to market, along with the processes required for scale up and supply chain integration.

Phase 1 of this collaborative project was successfully completed within 12 months. Phase 2, which is about to start, is expected to be a three to four year research project. For this next phase, Colloids is funding and supporting a full time Ph.D. researcher who will be based at University of Manchester with the Advanced nanomaterials Group led by Dr. Mark A. Bissett and Professor Ian A. Kinloch. The Ph.D. researcher will also be working with and supervised by key Colloids’ R & D people involved in the project.  

The potential benefits of 2D thermoplastic nanocomposites have long been recognized. The project team will investigate the applicability of nanocomposites based on graphene and other two-dimensional (2D) materials to a broad range of thermoplastic materials, including polyolefins, polyamides and polyesters, and to understand how mechanical, thermal, electrical, rheological and gas-barrier properties (among others) are affected by the production process and by the materials used.  

The main goal of this collaborative Ph.D. research project is to develop and upscale new polymer-graphene nanocomposites with enhanced properties and multifunctional capabilities that are not currently available. Key target markets for ‘next generation’graphene nanocomposite Colloids products include automotive, aerospace, electronics and electrical.

As the research project is through Graphene@Manchester, the collaborative project teambenefits from access to the extensive graphene research facilities at The University of Manchester: the National Graphene Institute (NGI), the Graphene Engineering Innovation Centre (GEIC), and theHenry Royce Institute. The University of Manchesteris a globally recognized centre of excellence for cutting edge graphene research, building upon the published work by Professor Andre Geim and Professor Konstantin Novoselov, who won the Nobel Prize in Physics in 2010 for isolating, characterising and contacting ground-breaking experiments regarding the two-dimensional material graphene.

Colloids Group is exhibiting with parent company, TOSAF Group Ltd. (Booth# Hall 8a / D01) at the K’19 Plastics & Rubber exhibition in Dusseldorf, Germany, which runs from 16-23 October 2019. Show visitors from companies interested in the graphene nanocomposites collaborative project can speak with technical people from the Colloids’ team who will be at the show.

Tags:  2D materials  Colloids Group  Graphene  Ian A. Kinloch  Mark A. Bissett  nanocomposites  nanomaterials  polymers  University of Manchester 

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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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3D printable 2D materials based inks show promise to improve energy storage devices

Posted By Graphene Council, The Graphene Council, Sunday, August 11, 2019
Updated: Sunday, August 4, 2019
For the first time, a team of researchers, from the School of Materials and the National Graphene Institute at The the University of Manchester have formulated inks using the 2D material MXene, to produce 3D printed interdigitated electrodes.

As published in Advanced Materials, these inks have been used to 3D print electrodes that can be used in energy storages devices such as supercapacitors.

MXene, a ‘clay-like’ two-dimensional material composed of early transition metals (such as titanium) and carbon atoms, was first developed by Drexel University. However, unlike most clays, MXene shows high electrical conductivity upon drying and is hydrophilic, allowing them to be easily dispersed in aqueous suspensions and inks.

Graphene was the world’s first two-dimensional material, more conductive than copper, many more times stronger than steel, flexible, transparent and one million times thinner than the diameter of a human hair.

Since its isolation, graphene has opened the doors for the exploration of other two-dimensional materials, each with a range of different properties. However, in order to make use of these unique properties, 2D materials need to be efficiently integrated into devices and structures. The manufacturing approach and materials formulations are essential to realise this.

Dr Suelen Barg who led the team said: “We demonstrate that large MXene flakes spanning a few atoms thick, and water can be independently used to formulate inks with very specific viscoelastic behaviour for printing. These inks can be directly 3D printed into freestanding architectures over 20 layers tall. Due to the excellent electrical conductivity of MXene, we can employ our inks to directly 3D print current collector-free supercapacitors. The unique rheological properties combined with the sustainability of the approach open many opportunities to explore, especially in energy storage and applications requiring the functional properties of 2D MXene in customized 3D architectures.”

Wenji and Jae, PhD students at the Nano3D Lab at the University, said: “Additive manufacturing offers one possible method of building customised, multi-materials energy devices, demonstrating the capability to capture MXene’s potential for usage in energy applications. We hope this research will open avenues to fully unlock the potential of MXene for use in this field.”

The unique rheological properties combined with the sustainability of the approach open many opportunities to explore, especially in energy storage and applications requiring the functional properties of 2D MXene in customized 3D architectures. Dr Suelen Barg, School of Materials

The performance and application of these devices increasingly rely on the development and scalable manufacturing of innovative materials in order to enhance their performance.

Supercapacitors are devices that are able to produce massive amounts of power while using much less energy than conventional devices. There has been much work carried out on the use of 2D materials in these types of devices due to their excellent conductivity as well as having the potential to reduce the weight of the device.

Potential uses for these devices are for the automotive industry, such as in electric cars as well as for mobile phones and other electronics.

Tags:  2D materials  3D Printing  Drexel University  Graphene  Suelen Barg  Supercapacito  University of Manchester 

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A novel graphene-matrix-assisted stabilization method will help unique 2D materials become a part of quantum computers

Posted By Graphene Council, The Graphene Council, Sunday, August 11, 2019
Updated: Monday, August 5, 2019
The family of 2D materials was recently joined by a new class, the monolayers of oxides and carbides of transition metals, which have been the subject of extensive theoretical and experimental research. These new materials are of great interest to scientists due to their unusual rectangular atomic structure and chemical and physical properties. 

Scientists are particularly interested in a unique 2D rectangular copper oxide cell, which does not exist in crystalline (3D) form, as opposed to most 2D materials, whether well known or discovered recently, which have a lattice similar to that of their crystalline (3D) counterparts. The main hindrance for practical use of monolayers is their low stability.

A group of scientists from MISiS, the Institute of Biochemical Physics of RAS (IBCP), Skoltech, and the National Institute for Materials Science in Japan (NIMS) discovered 2D copper oxide materials with an unusual crystal structure inside a two-layer graphene matrix using experimental methods.

“Finding that a rectangular-lattice copper-oxide monolayer can be stable under given conditions is as important as showing how the binding of copper oxide and a graphene nanopore and formation of a common boundary can lead to the creation of a small, stable 2D copper oxide cluster with a rectangular lattice. In contrast to the monolayer, the small copper oxide cluster’s stability is driven to a large extent by the edge effects (boundaries) that lead to its distortion and, subsequently, destruction of the flat 2D structure. Moreover, we demonstrated that binding bilayered graphene with pure copper, which never exists in the form of a flat cluster, makes the 2D metal layer more stable,” says Skoltech Senior Research Scientist Alexander Kvashnin.

The preferability of the copper oxide rectangular lattice forming in a bigraphene nanopore was confirmed by the calculations performed using the USPEX evolutionary algorithm developed by Professor at Skoltech and MIPT, Artem Oganov. The studies of the physical properties of the stable 2D materials indicate that they are good candidates for spintronics applications.

Tags:  2D materials  Alexander Kvashnin  Artem Oganov  Graphene  MIPT  Skoltech 

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New quantum phenomena helps to understand fundamental limits of graphene electronics

Posted By Graphene Council, The Graphene Council, Wednesday, July 31, 2019
Updated: Tuesday, July 30, 2019
A team of researchers from the Universities of Manchester, Nottingham and Loughborough have discovered quantum phenomena that helps to understand the fundamental limits of graphene electronics. As published in Nature Communications, the work describes how electrons in a single atomically-thin sheet of graphene scatter off the vibrating carbon atoms which make up the hexagonal crystal lattice.

By applying a magnetic field perpendicular to the plane of graphene, the current-carrying electrons are forced to move in closed circular “cyclotron” orbits. In pure graphene, the only way in which an electron can escape from this orbit is by bouncing off a “phonon” in a scattering event. These phonons are particle-like bundles of energy and momentum and are the “quanta” of the sound waves associated with the vibrating carbon atom. The phonons are generated in increasing numbers when the graphene crystal is warmed up from very low temperatures.

By passing a small electrical current through the graphene sheet, the team were able to measure precisely the amount of energy and momentum that is transferred between an electron and a phonon during a scattering event.

Their experiment revealed that two types of phonon scatter the electrons: transverse acoustic (TA) phonons in which the carbon atoms vibrate perpendicular to the direction of phonon propagation and wave motion (somewhat analogous to surface waves on water) and longitudinal acoustic (LA) phonons in which the carbon atoms vibrate back and forth along the direction of the phonon and the wave motion; (this motion is somewhat analogous to the motion of sound waves through air).

The measurements provide a very accurate measure of the speed of both types of phonons, a measurement which is otherwise difficult to make for the case of a single atomic layer. An important outcome of the experiments is the discovery that TA phonon scattering dominates over LA phonon scattering.

We were pleasantly surprised to find such prominent magnetophonon oscillations appearing in graphene. We were also puzzled why people had not seen them before, considering the extensive amount of literature on quantum transport in graphene. Laurence Eaves and Roshan Krishna Kumar, The University of Manchester

The observed phenomena, commonly referred to as “magnetophonon oscillations”, was measured in many semiconductors years before the discovery of graphene. It is one of the oldest quantum transport phenomena that has been known for more than fifty years, predating the quantum Hall effect. Whereas graphene possesses a number of novel, exotic electronic properties, this rather fundamental phenomenon has remained hidden.

Laurence Eaves & Roshan Krishna Kumar, co-authors of the work said: “We were pleasantly surprised to find such prominent magnetophonon oscillations appearing in graphene. We were also puzzled why people had not seen them before, considering the extensive amount of literature on quantum transport in graphene.”

Their appearance requires two key ingredients. First, the team had to fabricate high quality graphene transistors with large areas at the National Graphene Institute. If the device dimensions are smaller than a few micrometres the phenomena could not be observed.

Piranavan Kumaravadivel from The University of Manchester, lead author of the paper said: “At the beginning of quantum transport experiments, people used to study macroscopic, millimetre sized crystals. In most of the work on quantum transport on graphene, the studied devices are typically only a few micrometres in size. It seems that making larger graphene devices is not only important for applications but now also for fundamental studies.”

The second ingredient is temperature. Most graphene quantum transport experiments are performed at ultra-cold temperatures in-order to slow down the vibrating carbon atoms and “freeze-out” the phonons that usually break quantum coherence. Therefore, the graphene is warmed up as the phonons need to be active to cause the effect.

Mark Greenaway, from Loughborough University, who worked on the quantum theory of this effect said: “This result is extremely exciting - it opens a new route to probe the properties of phonons in two-dimensional crystals and their heterostructures. This will allow us to better understand electron-phonon interactions in these promising materials, understanding which is vital to develop them for use in new devices and applications.”

Tags:  2D materials  Graphene  Laurence Eaves  Loughborough University  Mark Greenaway  Piranavan Kumaravadivel  Roshan Krishna Kumar  University of Manchester  University of Nottingham 

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Graphene in Electronic Circuits

Posted By Graphene Council, The Graphene Council, Wednesday, July 31, 2019
Updated: Tuesday, July 30, 2019
Ever since graphene was discovered in 2004, researchers around the world have been working to develop commercially scalable applications for this high-performance material.

Graphene is 100 to 300 times stronger than steel at the atomic level and has a maximum electrical current density orders of magnitude greater than that of copper, making it the strongest, thinnest and, by far, the most reliable electrically conductive material on the planet. It is, therefore, an extremely promising material for interconnects, the fundamental components that connect billions of transistors on microchips in computers and other electronic devices in the modern world.

For over two decades, interconnects have been made of copper, but that metal encounters fundamental physical limitations as electrical components that incorporate it shrink to the nanoscale. “As you reduce the dimensions of copper wires, their resistivity shoots up,” said Kaustav Banerjee, a professor in the Department of Electrical and Computer Engineering. “Resistivity is a material property that is not supposed to change, but at the nanoscale, all properties change.”

As the resistivity increases, copper wires generate more heat, reducing their current-carrying capacity. It’s a problem that poses a fundamental threat to the $500 billion semiconductor industry. Graphene has the potential to solve that and other issues. One major obstacle, though, is designing graphene micro-components that can be manufactured on-chip, on a large scale, in a commercial foundry.

“Whatever the component, be it inductors, interconnects, antennas or anything else you want to do with graphene, industry will move forward with it only if you find a way to synthesize graphene directly onto silicon wafers,” Banerjee said. He explained that all manufacturing processes related to the transistors, which are made first, are referred to as the ‘front end.’ To synthesize something at the back-end — that is, after the transistors are fabricated — you face a tight thermal budget that cannot exceed a temperature of about 500 degrees Celsius. If the silicon wafer gets too hot during the back-end processes employed to fabricate the interconnects, other elements that are already on the chip may get damaged, or some impurities may start diffusing, changing the characteristics of the transistors.

Now, after a decade-long quest to achieve graphene interconnects, Banerjee’s lab has developed a method to implement high-conductivity, nanometer-scale doped multilayer graphene (DMG) interconnects that are compatible with high-volume manufacturing of integrated circuits. A paper describing the novel process was named one of the top papers at the 2018 IEEE International Electron Devices Meeting (IEDM),  from more than 230 that were accepted for oral presentations. It also was one of only two papers included in the first annual “IEDM Highlights” section of an issue of the journal Nature Electronics.

Banerjee first proposed the idea of using doped multi-layer graphene at the 2008 IEDM conference and has been working on it ever since. In February 2017 he led the experimental realization of the idea by Chemical Vapor Deposition (CVD) of multilayer graphene at a high temperature, subsequently transferring it to a silicon chip, then patterning the multilayer graphene, followed by doping. Electrical characterization of the conductivity of DMG interconnects down to a width of 20 nanometers established the efficacy of the idea that was proposed in 2008. However, the process was not “CMOS-compatible” (the standard industrial-scale process for making integrated circuits), since the temperature of CVD processes far exceed the thermal budget of back-end processes.

To overcome this bottleneck, Banerjee’s team developed a unique pressure-assisted solid-phase diffusion method for directly synthesizing a large area of high-quality multilayer graphene on a typical dielectric substrate used in the back-end CMOS process. Solid-phase diffusion, well known in the field of metallurgy and often used to form alloys, involves applying pressure and temperature to two different materials that are in close contact so that they diffuse into each other.

Banerjee’s group employed the technique in a novel way. They began by depositing solid-phase carbon in the form of graphite powder onto a deposited layer of nickel metal of optimized thickness. Then they applied heat (300 degrees Celsius) and nominal pressure to the graphite powder to help break down the graphite. The high diffusivity of carbon in nickel allows it to pass rapidly through the metal film.

How much carbon flows through the nickel depends on its thickness and the number of grains it holds. “Grains” refer to the fact that deposited nickel is not a single-crystal metal, but rather a polycrystalline metal, meaning it has areas where two single-crystalline regions meet each other without being perfectly aligned. These areas are called grain boundaries, and external particles — in this case, the carbon atoms — easily diffuse through them. The carbon atoms then recombine on the other surface of the nickel closer to the dielectric substrate, forming multiple graphene layers.

Banerjee’s group is able to control the process conditions to produce graphene of optimal thickness. “For interconnect applications, we know how many layers of graphene are needed,” said Junkai Jiang, a Ph.D. candidate in Banerjee’s lab and lead author of the 2018 IEDM paper. “So we optimized the nickel thickness and other process parameters to obtain precisely the number of graphene layers we want at the dielectric surface. “Subsequently, we simply remove the nickel by etching so that what’s left is only very high-quality graphene — virtually the same quality as graphene grown by CVD at very high temperatures,” he continued. “Because our process involves relatively low temperatures that pose no threat to the other fabricated elements on the chip, including the transistors, we can make the interconnects right on top of them.”

UCSB has filed a provisional patent on the process, which overcomes the obstacles that, until now, have prevented graphene from replacing copper. Bottom line: graphene interconnects help to create faster, smaller, lighter, more flexible, more reliable and more cost-effective integrated circuits. Banerjee is currently in talks with industry partners interested in potentially licensing this CMOS-compatible graphene synthesis technology, which could pave the way for what would be the first 2D material to enter the mainstream semiconductor industry.

Tags:  2D materials  CVD  Graphene  Graphite  Junkai Jiang  Kaustav Banerjee  Semiconductor  UC Santa Barbara 

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Unconventional phenomena triggered by acoustic waves in 2D materials

Posted By Graphene Council, The Graphene Council, Tuesday, July 30, 2019
Researchers at the Center for Theoretical Physics of Complex Systems (PCS), within the Institute for Basic Science (IBS, South Korea), and colleagues have reported a novel phenomenon, called Valley Acoustoelectric Effect, which takes place in 2D materials, similar to graphene. This research is published in Physical Review Letters and brings new insights to the study of valleytronics.

In acoustoelectronics, surface acoustic waves (SAWs) are employed to generate electric currents. In this study, the team of theoretical physicists modelled the propagation of SAWs in emerging 2D materials, such as single-layer molybdenum disulfide (MoS2). SAWs drag MoS2 electrons (and holes), creating an electric current with conventional and unconventional components. The latter consists of two contributions: a warping-based current and a Hall current. The first is direction-dependent, is related to the so-called valleys -- electrons' local energy minima -- and resembles one of the mechanisms that explains photovoltaic effects of 2D materials exposed to light. The second is due to a specific effect (Berry phase) that affects the velocity of these electrons travelling as a group and resulting in intriguing phenomena, such as anomalous and quantum Hall effects.

The team analyzed the properties of the acoustoelectric current, suggesting a way to run and measure the conventional, warping, and Hall currents independently. This allows the simultaneous use of both optical and acoustic techniques to control the propagation of charge carriers in novel 2D materials, creating new logical devices.

The researchers are interested in controlling the physical properties of these ultra-thin systems, in particular those electrons that are free to move in two dimensions, but tightly confined in the third. By curbing the parameters of the electrons, in particular their momentum, spin, and valley, it will be possible to explore technologies beyond silicon electronics. For example, MoS2 has two district valleys, which could be potentially used in the future for bit storage and processing, making it an ideal material to delve into valleytronics.

"Our theory opens a way to manipulate valley transport by acoustic methods, expanding the applicability of valleytronic effects on acoustoelectronic devices," explains Ivan Savenko, leader of the Light-Matter Interaction in Nanostructures Team at PCS.

Tags:  2D materials  Center for Theoretical Physics of Complex Systems  Electronics  Graphene  Institute for Basic Science  Ivan Savenko 

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Eli and Britt Harari Graphene Enterprise Award 2019 Winners Announced

Posted By Graphene Council, The Graphene Council, Tuesday, July 30, 2019
Two new technology businesses share this year’s £70,000 prize for novel applications of graphene and other 2D materials. The two teams, based at The University of Manchester, are addressing key societal challenges on future energy and food security. They are seeking breakthroughs by using 2D materials to produce hydrogen to generate energy, and by designing polymer hydrogels to increase food production.

The Eli and Britt Harari Enterprise Award, in association with Nobel Laureate Sir Andre Geim, is awarded each year to help the implementation of commercially-viable business proposals from students, post-doctoral researchers and recent graduates of The University of Manchester based on developing the commercial prospects of graphene and other 2D materials.

The first prize of £50,000 was awarded to NanoPlexus and its founding team Jae Jong Byun, Dr. Suelen Barg, Francis Moissinac, Wenji Yang and Thomas Moissinac. Jae and Wenji are undertaking their PhD studies in Dr. Suelen Barg’s research group (Nano3D), with Francis starting in September. Thomas is an aerospace engineering graduate from The University of Manchester. The team has worked under the Nano3D lab in formulating their idea into a marketable product.

NanoPlexus will be developing a range of products using their platform technology; the unique nano-material aerogel technology will offer cost-effective renewable hydrogen production with increased material efficiency for a sustainable green-economy.

Jae said: “Recently, there has been an increased footprint and sense of urgency to transition into renewable energy to tackle climate change. Our concept is ideally positioned to support this transition by acting as a stepping-stone for innovative technology growth into conventional energy systems. Our idea of 2D material-based cells supports the forecasted need of renewable energy implementation, as it uses low to zero carbon energy resources.”

Our commitment to the support of entrepreneurship across the University has never been stronger and is a vital part of our approach to the commercialisation of research. Professor Luke Georghiou, Deputy President and Deputy Vice-Chancellor

Francis added: “We are very grateful to Eli and Britt Harari for their generosity and for the support of the University, which will enable us to develop our novel concept that could one day make a meaningful difference; connecting innovation to convention.”

The runner-up, receiving £20,000, was AEH Innovative Hydrogel Ltd, founded by Beenish Siddique. Beenish has recently graduated with a PhD from the School of Materials. Her technology aims to provide an eco-friendly hydrogel to farmers that, not only increases crop production but also has potential to grow crops in infertile and water stressed lands, with minimum use of water and fertilisers.

Beenish said: “Many farmers, especially in third world countries with warmer climates, are interested in my product. I have a solution that offers higher crop yield with less water and fertiliser usage, hence, less greenhouse gases emission and a much cleaner environment.”

The quality of the business proposals presented in this year’s finals was exceptionally high. Professor Luke Georghiou, Deputy President and Deputy Vice-Chancellor of The University of Manchester and one of the judges for this year’s competition said: “Our commitment to the support of entrepreneurship across the University has never been stronger and is a vital part of our approach to the commercialisation of research. The support provided by Eli Harari over the last five years has enabled new and exciting ventures to be developed. It provides our winners the early-stage funding that is so vital to creating a significant business, while also contributing to health and social benefit. With support from our world-leading graphene research facilities I am certain that they are on the path to success.”

The winners will also receive support from groups across the University, including the University’s new state-of-the-art R&D facility, the Graphene Engineering Innovation Centre (GEIC); its leading support infrastructure for entrepreneurs, the Masood Enterprise Centre; as well as wider networks to help the winners take the first steps towards commercialising these early stage ideas.

The award is co-funded by the North American Foundation for The University of Manchester through the support of one of the University’s former physics students, Dr Eli Harari, founder of global flash-memory giant, SanDisk, and his wife, Britt. It recognises the role that high-level, flexible, early-stage financial support can play in the successful development of a business targeting the full commercialisation of a product or technology related to research in graphene and 2D materials.

Tags:  2D materials  AEH Innovative Hydrogel Ltd  Andre Geim  Beenish Siddique  Eli Harari  Graphene  Graphene Engineering Innovation Centre  Jae Jong Byun  Luke Georghiou  NanoPlexus  SanDisk  Suelen Barg  Thomas Moissinac  Wenji Yang 

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How to enlarge 2D materials as single crystals?

Posted By Graphene Council, The Graphene Council, Friday, May 31, 2019

What makes something a crystal? When all of its atoms are arranged in accordance with specific mathematical rules, we call the material a single crystal. Like the natural world has its unique symmetry just as snowflakes or honeycombs, the atomic world of crystals is designed by its own structure and symmetry. This material structure has a profound effect on its physical properties as well. Specifically, single crystals play an important role in inducing material's intrinsic properties to its full extent. Faced with the coming end of the miniaturization process that the silicon-based integrated circuit has allowed up to this point, huge efforts have been dedicated to find a single crystalline replacement for silicon.


In search for the transistor of the future, two-dimensional (2D) materials, especially graphene have been the subject of intense research around the world. Being thin and flexible as a result of being only a single layer of atoms, this 2D version of carbon even features unprecedented electricity and heat conductivity. However, the last decade's efforts for graphene transistors have been held up by physical restraints graphene allows no control over electricity flow due to the lack of band gap. Then, what about other 2D materials? A number of interesting 2D materials have been reported to have similar or even superior properties. Still, the lack of understanding in creating ideal experimental conditions for large-area 2D materials has limited their maximum size to just a few mm 2.

Scientists at the Center for Multidimensional Carbon Material (CMCM) within the Institute for Basic Science (IBS) (located in the Ulsan National Institute of Science and Technology (UNIST)) have presented a novel approach to synthesize large-scale of silicon wafer size, single crystalline 2D materials. Prof. Feng Ding and Ms. Leining Zhang in collaboration with their colleagues in Peking University, China and other institutes have found a substrate with a lower order of symmetry than that of a 2D material that facilitates the synthesis of single crystalline 2D materials in a large area. "It was critical to find the right balance of rotational symmetries between a substrate and a 2D material," notes Prof. Feng Ding, one of corresponding authors of this study. The researchers successfully synthesized hBN single crystals of 10*10 cm2 by using a new substrate: a surface nearby Cu (110) that has a lower symmetry of (1) than hBN with (3).

Then, why does symmetry matters? Symmetry, in particular rotational symmetry, describes how many times a certain shape fits on to itself during a full rotation of 360 degrees. The most efficient method to synthesize large-area and single crystals of 2D materials is to arrange layers over layers of small single crystals and grow them upon a substrate. In this epitaxial growth, it is quite challenging to ensure all of the single crystals are aligned in a single direction. Orientation of the crystals is often affected by the underlying substrate. By theoretical analysis, the IBS scientists found that an hBN island (or a group of hBN atoms forming a single triangle shape) has two equivalent alignments on the Cu(111) surface that has a very high symmetry of (6). "It was a common view that a substrate with high symmetry may lead to the growth of materials with a high symmetry. It seemed to make sense intuitively, but this study found it is incorrect," says Ms. Leining Zhang, the first author of the study.

Previously, various substrates such as Cu(111) have been used to synthesize single crystalline hBN in a large area, but none of them were successful. Every effort ended with hBN islands aligning along in several different directions on the surfaces. Convinced by the fact that the key to achieve unidirectional alignment is to reduce the symmetry of the substrate, the researchers made tremendous efforts to obtain vicinal surfaces of a Cu(110) orientation; a surface obtained by cutting a Cu(110) with a small tilt angle. It is like forming physical steps on Cu. As a hBN island tends to place in parallel to the edge of each step, it gets only one preferred alignment. The small tilt angle lowers the symmetry of the surface as well.

They eventually found that a class of vicinal surfaces of Cu (110) can be used to support the growth of hBN with perfect alignment. On a carefully selected substrate with the lowest symmetry or the surface will repeat itself only after a 360degree rotation, hBN has only one preferred direction of alignment. The research team of Prof. Kaihui Liu in Peking University, has developed a unique method to anneal a large Cu foil, up to 10*10 cm2, into a single crystal with the vicinal Cu (110) surface and, with it, they have achieved the synthesis of hBN single crystals of same size.

Besides flexibility and ultrathin thickness, emerging 2D materials can present extraordinary properties when they get enlarged as single crystals. "This study provides a general guideline for the experimental synthesis of various 2D materials. Besides the hBN, many other 2D materials could be synthesized with the large area single crystalline substrates with low symmetry," says Prof. Feng Ding. Notably, hBN is the most representative 2D insulator, which is different from the conductive 2D materials, such as graphene, and 2D semiconductors, such as molybdenum disulfide (MoS2). The vertical stacking of various types of 2D materials, such as hBN, graphene and MoS2, would lead to a large number of new materials with exceptional properties and can be used for numerous applications, such as high-performance electronics, sensors, or wearable electronics."

Tags:  2D materials  Center for Multidimensional Carbon Material  Feng Ding  Graphene  Kaihui Liu  Peking University  Semiconductors 

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