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New Device Can Measure Toxic Lead Within Minutes

Posted By Graphene Council, Wednesday, August 26, 2020
Rutgers researchers have created a miniature device for measuring trace levels of toxic lead in sediments at the bottom of harbors, rivers and other waterways within minutes – far faster than currently available laboratory-based tests, which take days.

The affordable lab-on-a-chip device could also allow municipalities, water companies, universities, K-12 schools, daycares and homeowners to easily and swiftly test their water supplies. The research is published in the IEEE Sensors Journal.

“In addition to detecting lead contamination in environmental samples or water in pipes in homes or elementary schools, with a tool like this, someday you could go to a sushi bar and check whether the fish you ordered has lead or mercury in it,” said senior author Mehdi Javanmard, an associate professor in the Department of Electrical and Computer Engineering in the School of Engineering at Rutgers University–New Brunswick.

“Detecting toxic metals like lead, mercury and copper normally requires collecting samples and sending them to a lab for costly analysis, with results returned in days,” Javanmard said. “Our goal was to bypass this process and build a sensitive, inexpensive device that can easily be carried around and analyze samples on-site within minutes to rapidly identify hot spots of contamination.”

The research focused on analyzing lead in sediment samples.  Many river sediments in New Jersey and nationwide are contaminated by industrial and other waste dumped decades ago. Proper management of contaminated dredged materials from navigational channels is important to limit potential impacts on wildlife, agriculture, plants and food supplies. Quick identification of contaminated areas could enable timely and cost-effective programs to manage dredged materials.

The new device extracts lead from a sediment sample and purifies it, with a thin film of graphene oxide as a lead detector. Graphene is an atom thick layer of graphite, the writing material in pencils.

More research is needed to further validate the device’s performance and increase its durability so it can become a viable commercial product, possibly in two to four years.

This project was done in collaboration with the Department of Electrical and Computer Engineering and Rutgers’ Center for Advanced Infrastructure and Transportation (CAIT). It was funded by CAIT, the USDOT-University Transportation Research Center–Region II.

Tags:  Graphene  graphene oxide  Mehdi Javanmard  Rutgers University  Sensors  water purification 

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Using brainwaves to command and control autonomous vehicles

Posted By Graphene Council, Wednesday, August 26, 2020
Researchers at the University of Technology Sydney (UTS) are using smart sensors and advanced brain signal decoders to improve communication between human brains and robots.

A team led by Distinguished Professor CT Lin and Professor Francesca Iacopi will embark on a two-year project with the Department of Defence to examine how cutting-edge technologies could use brainwaves to command and control autonomous vehicles.

Distinguished Professor CT Lin, Director of The UTS Computational Intelligence and Brain Computer Interface Centre, is a leading researcher in brain computer interfaces (BCI). 

An expert in wearable and wireless devices, Professor Lin combines human physiological information with artificial intelligence (AI) to develop advanced monitoring and feedback systems.

“I want to improve the flow of information from humans to robots, so humans can make better informed decisions,” said Professor Lin.

An internationally-recognised expert in nanotechnology, Professor Francesca Iacopi will design and produce the graphene-based smart sensors required for the wearable device.  

Professor Iacopi has developed a novel method to embed graphene-based microdevices on silicon wafers. The process can be adapted for large-scale manufacturing. 

Professor Iacopi said most graphene synthesis methods are not compatible with semiconductor technologies, precluding miniaturised applications. 

“The new synthesis I developed will help obtain graphene from sources that make it more accessible and affordable.”

The project has received $1.2 million in funding from the Defence Innovation Hub.

The innovative technology has potential applications across multiple sectors including MedTech and biotechnology.

Tags:  artificial intelligence  Chin Teng Lin  Francesca Iacopi  Graphene  Sensors  University of Technology Sydney 

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Posted By Graphene Council, Wednesday, August 26, 2020
In his long career at NETL, McMahan Gray has experienced more than a few successes.

For example, the award-winning research chemist has made valuable contributions to remove carbon from industrial emissions and extract rare earth elements (REEs) from coal byproducts, wastewater and even acid mine drainage.

Another ground-breaking contribution may be just around the corner. As part of an ongoing research effort, Gray serves on an NETL team that’s writing a new chapter in the long productive history of coal that may revolutionize how the mineral is used in the future.

The team has found that rather than combust coal to produce energy, it can be used in new ways to fuel a transformation in carbon-based, high-tech manufacturing to produce safer cars, faster computers, stronger homes, bridges and highways, and even life-saving biosensors to confirm the presence of disease in the human body.

“We were looking for a rebirth in how coal can be used when we began our project,” said Gray, who has worked at the Lab for 34 years. “I think the rebirth we will see is going to produce sophisticated new uses for coal that have absolutely nothing to do with burning it to produce electricity.”

Gray and his NETL colleagues have developed a patent-pending manufacturing process that converts lignite, bituminous and anthracite ranks of coal into graphene, whose superior strength and optical and electrical conductivity properties make it a game-changing material. (Shi, Fan; Matranga, Christopher; Gray, McMahan; Ji, Tuo., Production of Graphene-structured Products from Coal Using Thermal Molten Salt Process, U.S. Non-provisional Patent No. 16/369,753, 2019).

NETL’s low-cost coal-to-graphene, or C2G, manufacturing process will not only generate a superior material to produce high-value products; it also will create new environmentally friendly uses for one of the nation’s greatest resources — its abundant reserves of coal.

According to Gray, it takes a solid team effort to achieve success. “Teamwork, the leadership of an excellent principal investigation (Matranga) and the outstanding work of my colleagues have enabled us to develop this process so coal can be used in new and innovative ways,” Gray said. 

Discovered in 2004, graphene is only one atomic layer thick, but it’s 100 times stronger than construction steel and 1.6 times more electrically conductive than copper electrical wire. Graphene is a form of carbon. Both graphene and carbon possess the same atoms, but they are arranged in different ways, giving each material its own unique properties. For graphene, those differences produce extraordinary strength.  

However, the high cost of existing supplies of graphene have limited its use. “NETL’s technology reduces the cost of manufacturing graphene by up to tenfold while producing a significantly higher-quality material than what is currently available on the market,” Gray said.

In the future, the team envisions using graphene to build lighter and stronger cars. Gray believes it also can be used to create advanced lightweight body armor for U.S. troops.

Because graphene is one of the lightest, strongest and thinnest materials ever discovered, it makes an ideal additive to improve the mechanical properties and durability of cement and produce battery and electrode materials, 3D printing composites, water- and stain- resistant textiles, catalyst materials and supports, and other items.

NETL also has produced graphene quantum dots — small fluorescent nanoparticles with sheet-like structures — and sent them to the University of Illinois at Urbana-Champaign where they are used to fabricate an advanced type of computer memory chip called a memristor. Recent testing has shown that memristors made with NETL graphene have outperformed those made with conventional materials.

In addition, the project team is collaborating with Ramaco Carbon, a Wyoming-based coal technology company, to take advantage of graphene’s superb electrical conductivity to develop new biosensor products that can quickly confirm the presence of Lyme disease, Zika virus or the amount of medication in a blood sample.

Gray is no stranger to advancing ground-breaking projects.

He led NETL researchers who developed the basic immobilized amine sorbent (BIAS) process to capture carbon dioxide (CO2) from coal-burning power plants. Recognizing that the BIAS approach could do more than capture CO2 from coal combustion, Gray has worked to adapt the technology of sorbents, which are designed to absorb targeted chemical compounds, to remove heavy metals, including lead, from public water supplies and recover valuable rare earth elements (REEs) from acid mine discharges and other sources.

REEs, which are needed to produce high-performance optics and lasers, as well as powerful magnets, superconductors, solar panels and valuable consumers products such as smart phones and computer hard drives, are abundant in nature but are often found in low concentrations and are challenging to extract.

Recently, while working on the coal-to-graphene project, Gray made another exciting discovery that directly benefits his efforts in REE extraction. Gray has found that the water used in the coal-to-graphene process contains REEs in the range of 600 parts per million. “In the field of REE research, that’s a very high extraction rate,” Gray said.

“I call it a ‘double hit,’ which sometimes happens when research on one project produces a positive finding to benefit another project,” said Gray, who received a prestigious R&D 100 award in 2012 for the BIAS technology’s carbon capture application.

Gray is listed as the primary or secondary inventor on 21 patents, and his work has been cited in more than 120 scholarly papers. His other notable honors include the Federal Laboratory Consortium Mid-Atlantic Region Award for Technology Transfer and the Federal Laboratory Consortium National Award for Excellence in Technology Transfer.

He has also received the Hugh Guthrie Award for Innovation as one of NETL’s leading scientists. In 2018, he was awarded a Gold Medal for “Outstanding Contribution to Science (Non-Medical)” from the Federal Executive Board for Excellence in the Government.

The Chemistry Department at the University of Pittsburgh has announced it will present Gray with its 2020 Distinguished Alumni Award for his work advancing innovative technologies while serving as a mentor who has inspired hundreds of students and colleagues.

For Gray, NETL’s revolutionary graphene project rejuvenates coal for high-value uses. “Coal gets a bad rap,” said Gray, who also serves as pastor of Second Baptist Church of Penn Hills near Pittsburgh, Pennsylvania.

“The molecular structure behind coal is amazing. There’s really so much more we can do with coal,” he added.

Tags:  Battery  Biosensor  composites  Energy  Graphene  National Energy Technology Laboratory 

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Nanoelectromechanical sensors based on suspended 2D materials

Posted By Graphene Council, Wednesday, August 26, 2020
An international team of researchers have recently published a review article on nanoelectromechanical (NEMS) sensors based on suspended two-dimensional (2D) materials in the journal Research ("Nanoelectromechanical Sensors Based on Suspended 2D Materials"), an open-access multidisciplinary journal launched in 2018 as the first journal in the Science Partner Journal (SPJ) program.

The paper is an invited contribution to a special issue on “Progress and challenges in emerging 2D nanomaterials – preparation, processing, and device integration”, and has the purpose of contributing to the development of the field of 2D materials for sensor applications and to their integration with conventional semiconductor technology.

“I believe NEMS sensors based on 2D materials will be essential for satisfying the demand for integrated, high-performance sensors set by applications such as the Internet of Things (IoT) and autonomous mobility”, says Lemme, first author of the paper.

The review summarizes the many studies that have successfully shown the feasibility of using membranes of 2D materials in pressure sensors, microphones, mass and gas sensors – explaining the different sensor concepts and giving an overview of the relevant material properties, fabrication routes, and operation principles.

“Two-dimensional materials are ideally suited for sensors”, says Lemme, “as they allow realizing free-standing structures that are just one of a few atoms thick. This ultimate thinness can be a decisive advantage when it comes to nanoelectromechanical sensors, since the performance often depends critically on the thickness of the suspended part. Furthermore, many 2D materials have unique electrical, mechanical and optical properties that can be exploited for completely new concepts of sensor devices.”

The review – which includes contributions from RWTH Aachen University, AMO GmbH, Universität der Bundeswehr Munich, KTH Royal Institute of Technology, TU Delft, Infineon and the Kavli Institute of Nanoscience – discusses the different readout and integration methods of different sensors based on 2D materials, and provides comparisons against the state of the art devices to show both the challenges and the promises of 2D-materials based nanoelectromechanical sensing.

“Proof-of-concept sensor devices based on suspended 2D materials are almost always smaller than their conventional counterparts, show improved performances, and sometimes even completely novel functionalities”, says Peter G. Steeneken, leader of work-package 6 (Sensors) in the Graphene Flagship and co-author of the paper. “However, there are still enormous challenges to demonstrate that 2D material-based NEMS sensors can outperform conventional devices on all important aspects – for example, the establishment of high-yield manufacturing capabilities. The Graphene Flagship represents the ideal platform to address these challenges, as it fosters collaborations between world-leading groups to achieve a set of well-defined goals. This paper is an example of how, by bringing together complementary expertise, we can achieve more.”

Tags:  2D materials  AMO GmbH  Graphene  Graphene Flagship  Infineon  Kavli Institute of Nanoscience  KTH Royal Institute of Technology  Max Lemme  RWTH Aachen University  Sensors  TU Delft  Universität der Bundeswehr Munich 

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Upgraded cleanroom facilities will give UCLA advanced nanofabrication capabilities

Posted By Graphene Council, Wednesday, August 26, 2020

UCLA’s high-tech capabilities for creating atomically tiny devices and materials are undergoing a multimillion-dollar upgrade.

The enhancements include adding state-of-the-art fabrication equipment to its existing cleanrooms — specialized laboratories where the air is free from dust and other particles. The changes will allow researchers to build new generations of small devices, such as computer chips that mimic how the brain works, ultra high-efficiency batteries and solar panels, and even biological sensors for rapid and portable diagnosis.

As part of the upgrade, two existing cleanrooms will merge under a single operation — called the UCLA Nanofabrication Laboratory, or UCLA NanoLab for short. The new entity combines resources from the UCLA Samueli School of Engineering’s Nanoelectronics Research Facility and the California NanoSystems Institute at UCLA’s Integrated Systems Nanofabrication Cleanroom. The upgrades, which began this year, should be complete in 2022.

The UCLA NanoLab is available to the campus community, as well as to researchers from other institutions and high-tech companies. Hundreds of businesses have already used UCLA’s cleanrooms. The facility has remained active during the COVID-19 pandemic, although applications to use it are subject to campus guidance designed to limit the spread of the disease. 

The upgrades are being made possible by a combined multimillion-dollar investment from UCLA Engineering, CNSI and the office of UCLA’s vice chancellor of research.

“This joint investment is an important demonstration of a strategic partnership with an impact that will extend across campus and beyond,” said Adam Stieg, an associate director of CNSI responsible for the institute’s technology centers. “Providing this type of advanced research infrastructure will accelerate the translation of early-stage scientific discoveries into new technologies and knowledge-driven enterprises.”

Cleanrooms help prevent contamination of the tiny experimental devices researchers are studying or building. On a day with “good” outdoor air quality, there can be millions of particles of dust, pollen and microbes in each cubic foot of air. By contrast, the cleanest area of the UCLA NanoLab will have less than 10 particles per cubic foot.

The UCLA NanoLab will offer state-of-the-art resources for the fabrication of devices at the nanoscale — items so small that they are measured in one-billionths of a meter. Additionally, UCLA is the only institution in Southern California that enables researchers to work with biological materials — such as what’s needed to build next-generation biosensors — within a fully functional nanofabrication facility.

Some of the upgrades will build on UCLA’s established excellence in semiconductor lithography, the drawing of patterns onto the silicon wafers that form the foundation of integrated circuits. New equipment will enhance the campus’s capabilities for subsequent steps in the process — depositing functional materials onto the patterns, etching away unneeded parts of the wafers and analyzing the characteristics of the resulting devices.

This added equipment will enable researchers to work with emerging materials that combine metal with oxygen or nitrogen, with potential applications including greener electrical power and brain-mimicking computer chips.

“We’re creating more possibilities for users,” said You-Sheng “Wilson” Lin, who oversees day-to-day operations as director of the UCLA NanoLab. “With the new tools, UCLA investigators can be even more creative about conceiving their research programs.”

The NanoLab location in CNSI will house a full suite of equipment to support most common nanofabrication processes. The location at UCLA Samueli, which is in the nearby Engineering IV building, will host equipment for specialized processes such as advanced etching and continue to be used as a teaching laboratory for UCLA students in engineering and the sciences.

Beyond campus researchers, one company that has used UCLA’s cleanrooms is Carbonics Inc., which makes energy-efficient wireless chips integrating carbon nanotubes, hollow cylinders of graphene that help lower power consumption and improve performance. The business’s foundational research began at UCLA, and the company emerged from CNSI’s Magnify startup incubator, which provides lab space and other support for entrepreneurs. According to Carbonics co-founder Kos Galatsis, the resources at UCLA were integral to launching the business.

“The facility has some unique capabilities when it comes to semiconductor fabrication that don’t exist anyplace else,” said Galatsis, the company’s CEO and chairman, who was an associate adjunct professor of materials science at UCLA. “Our critical activities have taken place at UCLA, so the impact is tremendous.”

Stieg said the investment in nanofabrication will have broad-ranging impacts.

“With our capabilities modernized and renewed, the UCLA NanoLab will provide a unique resource for Southern California,” he said.

Tags:  Adam Stieg  Carbonics  CNSI  Graphene  Kos Galatsis  Sensors  University of California 

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Beyond chip-and-PIN: graphene’s quick, hygienic solution to restaurant payment

Posted By Graphene Council, Wednesday, August 26, 2020
A new graphene-based contactless payment system, developed in collaboration with the University of Manchester, has begun a restaurant pilot that could pave the way for the end of chip-and-PIN, cutting customer wait-time and reducing the risk of infectious transmission.

‘Payper’ allows the customer to tap their phone on a smart till receipt that features a printed electronic antenna. The smartphone reads data from the antenna, triggering the bill, which is shown via the customer’s default browser. Android or Apple Pay checkout is then completed with two clicks, in less than five seconds with no app required.

Strength and flexibility

The role of graphene in the antenna is to provide high flexibility, conductivity and mechanical strength, which can be imparted onto the tight and variable curvature of the till roll.

The project is led by Manchester start-up Payper Technologies, co-founded by Dr Thanasis Georgiou and Renate Kalnina (pictured right). Thanasis said: “Payper’s antennas combines graphene with metals and other components to realise a near-field communication device that can used as a direct swap for existing restaurant till rolls. 

“By introducing just a small amount of graphene in the manufacturing process, we can translate its unique range of benefits into our ‘smart’ receipt rolls,” he added.

Lowry trial

The team has begun a live trial of the system at the River Restaurant of The Lowry Hotel in Salford.

 “We are delighted to be the flagship hotel in the UK trialling this new enhanced safety payment method to our customers,” said Adrian Ellis, General Manager at The Lowry Hotel.

“The University of Manchester first isolated graphene, so it really is a privilege to be using a product that not only makes the customer journey safer and more convenient, but is also supportive of the city in which the product was founded.”

Thanasis added: “The trial will be used to demonstrate the technology and provide validation of this pay-at-table solution, along with potentially demonstrating other benefits for restaurants, including increasing customer lifetime value, repeat visits and tips, and reducing table-turn time”.

Bridging the gap

Concurrent with the Lowry Hotel trial, the team is conducting further research and development on the system at the University’s Graphene Engineering Innovation Centre, supported by the European Regional Development Fund (ERDF) ‘Bridging the Gap’ programme. This will include moves towards an ‘all-graphene’ system, removing the metal components to make the product more sustainable and recyclable.

James Baker, CEO of Graphene@Manchester said: “This is a great example of how we can help industry partners - including local SMEs - to accelerate graphene products towards the marketplace and deliver real-world benefits.

“Payper isn’t just about convenience,” he added. “The card machine is the one thing that all the waiting staff and at least one person from every table will touch over the course of a shift in a restaurant. If you can reduce those touchpoints with a truly contactless system, you have an elegant solution to reducing the risk of Covid transmission.”

Tags:  Graphene  Graphene Engineering Innovation Centre  James Baker  Payper Technologies  Renate Kalnina  Thanasis Georgiou  University of Manchester 

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Posted By Graphene Council, Tuesday, August 25, 2020

Recent studies on gene, inhalation and dermal toxicity of few-layer graphene have revealed much lower health risk than expected. This could pave the way for graphene as a young member of the nanocarbons family to become the “heir presumptive” to the long-reigning carbon black. Read the entire article


Tags:  Graphene  Healthcare  nanocarbons  NanoXplore  Nima Moghimian  Soroush Nazarpour 

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Trapping and controlling light at the interface of atomically thin nanomaterials

Posted By Graphene Council, Friday, August 21, 2020
Light can partake in peculiar phenomena at the nanoscale. Exploring these phenomena can unlock sophisticated applications and provide useful insights into the interactions between light waves and other materials.

In a recent study, scientists at Cornell University propose a novel method by which nanoscale light can be manipulated and transported. These special modes of light transport are known to arise at finely tuned interfaces between slightly different nanomaterials. Minwoo Jung, lead researcher on this study, illustrates this concept through a simple analogy: "A floating tube has a hole in the middle, but a normal balloon doesn't. No matter how you squeeze the round balloon, it cannot be reshaped like a donut-at least not without popping the balloon, re-knitting the rubber, and re-injecting the air. Thus, a tube and a balloon are distinct in their topology because they are not connected through a smooth deformation."

Jung further explains that physicists have been interested in gluing two topologically distinct materials side by side so that one of them acts like a balloon and the other like a tube. This means that, at their interface, a process that connects these two materials must occur, much like the poking/popping/re-knitting/re-injecting from a balloon to a tube. Under the right conditions, this process can give rise to a strong channel for transmitting energy or information along the interface. Because this process can be applied to light (which acts as a carrier of energy or information), this branch of physics is called topological photonics.

Jung and his team combined the fascinating concept of topological photonics with an innovative technique that traps light in an atomically thin material. This method brought together two rapidly emerging fields in applied and fundamental physics: graphene nanolight and topological photonics. Jung says, "Graphene is a promising platform for storing and controlling nanoscale light and could be key in the development of on-chip and ultracompact nanophotonic devices, such as waveguides and cavities."

The research team ran simulations involving a graphene sheet layered on a nanopatterned material that functions as a metagate. This honeycomb-like metagate consists of a solid layer of material with holes of different sizes, centered at the vertices of the hexagons. The varying radii of these holes affect the way in which the photons pass through the material. The scientists found that strategically "gluing" together two different metagates creates a topological effect that confines photons at their interface in a predictable, controllable manner.

Different choices of metagate designs demonstrate the dimensional hierarchy of the device's topology. Specifically, depending on the metagate geometry, nanolight can be made to flow along one-dimensional edges of the topological interface or can be topologically stored at zero-dimensional (point-like) vertices. Moreover, the metagate allows for on-and-off electric switching of these waveguides or cavities. Such battery-operated topological effects can benefit the technological adoption of topological photonics in practical devices.

Jung's team is optimistic that the synergistic combination of graphene nanolight and topological photonics will spur advances in relevant research areas, like optics, material sciences, and solid-state physics. Their graphene-based material system is simple, efficient, and suitable for nanophotonic applications: a step forward in harnessing the full potential of light.

Tags:  Cornell University  Graphene  Minwoo Jung  photonics 

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Graphene sensors find subtleties in magnetic fields

Posted By Graphene Council, Friday, August 21, 2020
As with actors and opera singers, when measuring magnetic fields it helps to have range. Cornell researchers used an ultrathin graphene “sandwich” to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

The group’s paper, “Magnetic Field Detection Limits for Ultraclean Graphene Hall Sensors,” published Aug. 20 in Nature Communications.

The team was led by Katja Nowack, assistant professor of physics in the College of Arts and Sciences and the paper’s senior author.

Nowack’s lab specializes in using scanning probes to conduct magnetic imaging. One of their go-to probes is the superconducting quantum interference device, or SQUID, which works well at low temperatures and in small magnetic fields.

“We wanted to expand the range of parameters that we can explore by using this other type of sensor, which is the Hall-effect sensor,” said doctoral student Brian Schaefer, the paper’s lead author. “It can work at any temperature, and we’ve shown it can work up to high magnetic fields as well. Hall sensors have been used at high magnetic fields before, but they’re usually not able to detect small magnetic field changes on top of that magnetic field.”

The Hall effect is a well-known phenomenon in condensed matter physics. When a current flows through a sample, it is bent by a magnetic field, creating a voltage across both sides of the sample that is proportional to the magnetic field.

Hall-effect sensors are used in a variety of technologies, from cellphones to robotics to anti-lock brakes. The devices are generally built out of conventional semiconductors like silicon and gallium arsenide.

Nowack’s group decided to try a more novel approach. The last decade has seen a boom in uses of graphene sheets – single layers of carbon atoms, arranged in a honeycomb lattice. But graphene devices often fall short of those made from other semiconductors when the graphene sheet is placed directly on a silicon substrate; the graphene sheet “crumples” on the nanoscale, inhibiting its electrical properties.

Nowack’s group adopted a recently developed technique to unlock graphene’s full potential – sandwiching it between sheets of hexagonal boron nitride. Hexagonal boron nitride has the same crystal structure as graphene but is an electrical insulator, which allows the graphene sheet to lie flat. Graphite layers in the sandwich structure act as electrostatic gates to tune the number of electrons that can conduct electricity in the graphene.

The sandwich technique was pioneered by co-author Lei Wang, a former postdoctoral researcher with the Kavli Institute at Cornell for Nanoscale Science. Wang also worked in the lab of co-senior author Paul McEuen, the John A. Newman Professor of Physical Science and co-chair of the Nanoscale Science and Microsystems Engineering (NEXT Nano) Task Force, part of the provost’s Radical Collaboration initiative.

“The encapsulation with hexagonal boron nitride and graphite makes the electronic system ultraclean,” Nowack said. “That allows us to work at even lower electron densities than we could before, and that’s favorable for boosting the Hall-effect signal we are interested in.”

The researchers were able to create a micron-scale Hall sensor that functions as well as the best Hall sensors reported at room temperature while outperforming any other Hall sensor at temperatures as low as 4.2 kelvins (or minus 452.11 degrees Fahrenheit).

The graphene sensors are so precise they can pick out tiny fluctuations in a magnetic field against a background field that is larger by six orders of magnitude (or a million times its size). Detecting such nuances is a challenge for even high-quality sensors because in a high magnetic field, the voltage response becomes nonlinear and therefore more difficult to parse.

Nowack plans to incorporate the graphene Hall sensor into a scanning probe microscope for imaging quantum materials and exploring physical phenomena, such as how magnetic fields destroy unconventional superconductivity and the ways that current flows in special classes of materials, such as topological metals.

“Magnetic field sensors and Hall sensors are important parts of many real-world applications,” Nowack said. “This work puts ultraclean graphene really on the map for being a superior material to build Hall probes out of. It wouldn’t be really practical for some applications because it’s hard to make these devices. But there are different pathways for materials growth and automated assembly of the sandwich that people are exploring. Once you have the graphene sandwich, you can put it anywhere and integrate it with existing technology.”

Tags:  Cornell University  Graphene  Katja Nowack  Semiconductors  Sensors 

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Cambrian is the Proud Canadian Distributor for Applied Graphene Materials

Posted By Graphene Council, Friday, August 21, 2020
Maroon Group, a world-class distributor of specialty chemicals and ingredients across North America, is excited to announce that it has signed a distribution agreement with Applied Graphene Materials. 

Maroon Group’s CASE and technical sales and support team will leverage its extensive customer network to introduce AGM’s proprietary Genable® graphene dispersions technology into the United States and Canadian coatings and polymers markets.

“I am delighted to announce Maroon Group as a very strong partner to help AGM drive commercial uptake of our graphene products in the North American market,” Adrian Potts, AGM’s CEO, said. “Maroon Group has leading expertise in additive sales and customer service, which is essential to support sales at this early stage of the graphene market’s development. With decades of experience in the region, their impressive network and consumer relationships will open up significant potential for AGM.

“The team at Maroon Group is very excited to partner with Applied Graphene Materials,” Tom Papasso, Vice President, Principal Management – CASE, Maroon Group, said. “Their unique line of graphene dispersions is a perfect example of how Maroon Group strives to bring real innovation and value to our customers.”

Tags:  Adrian Potts  Applied Graphene Materials  Coatings  Graphene  Maroon Group  polymers  Tom Papasso 

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