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#An easy, scalable and direct method for synthesizing graphene in silicon microelectronics: Korean researchers grow 4-inch diameter, high-quality, multi-layer graphene on desired silicon substrates,
an important step for harnessing graphene in commercial silicon microelectronics Abstract: In the last decade, graphene has been studied intensively for its unique optical, mechanical, electrical and structural properties.
The one-atom-thick carbon sheets could revolutionize the way electronic devices are manufactured and lead to faster transistors, cheaper solar cells, new types of sensors and more efficient bioelectric sensory devices.
As a potential contact electrode and interconnection material, wafer-scale graphene could be an essential component in microelectronic circuits,
but most graphene fabrication methods are not compatible with silicon microelectronics, thus blocking graphene's leap from potential wonder material to actual profit-maker.
Now researchers from Korea University in Seoul, have developed an easy and microelectronics-compatible method to grow graphene
and have synthesized successfully wafer-scale (four inches in diameter), high-quality, multi-layer graphene on silicon substrates.
The method is based on an ion implantation technique, a process in which ions are accelerated under an electrical field and smashed into a semiconductor.
The impacting ions change the physical, chemical or electrical properties of the semiconductor. In a paper published this week in the journal Applied Physics Letters, from AIP Publishing,
which takes graphene a step closer to commercial applications in silicon microelectronics.""For integrating graphene into advanced silicon microelectronics, large-area graphene free of wrinkles, tears and residues must be deposited on silicon wafers at low temperatures,
which cannot be achieved with conventional graphene synthesis techniques as they often require high temperatures, "said Jihyun Kim, the team leader and a professor in the Department of Chemical and Biological engineering at Korea University."
"Our work shows that the carbon ion implantation technique has great potential for the direct synthesis of wafer-scale graphene for integrated circuit technologies."
"Discovered just over a decade ago, graphene is considered now the thinnest, lightest and strongest material in the world.
Graphene is completely flexible and transparent while being inexpensive and nontoxic, and it can conduct electricity as well as copper,
carrying electrons with almost no resistance even at room temperature, a property known as ballistic transport. Graphene's unique optical, mechanical and electrical properties have lead to the one-atom-thick form of carbon being heralded as the next generation material for faster, smaller, cheaper and less power-hungry electronics."
"In silicon microelectronics, graphene is a potential contact electrode and an interconnection material linking semiconductor devices to form the desired electrical circuits,
"said Kim.""This renders high processing temperature undesirable, as temperature-induced damage, strains, metal spiking
"Thus, although the conventional graphene fabrication method of chemical vapor deposition is used widely for the large-area synthesis of graphene on copper and nickel films,
000 degrees Celsius and a subsequent transfer process of the graphene from the metallic film to the silicon."
"The transferred graphene on the target substrate often contains cracks, wrinkles and contaminants,"said Kim."
"Thus, we are motivated to develop a transfer-free method to directly synthesize high quality, multilayer graphene in silicon microelectronics."
The nickel layer, with high carbon solubility, is used as a catalyst for graphene synthesis. The process is followed then by high temperature activation annealing (about 600 to 900 degrees Celsius) to form a honeycomb lattice of carbon atoms, a typical microscopic structure of graphene.
Kim explained that the activation annealing temperature could be lowered by performing the ion implantation at an elevated temperature.
multi-layer graphene by varying the ambient pressure, ambient gas, temperature and time during the treatment.
as the graphene layer thickness can be determined precisely by controlling the dose of carbon ion implantation.""Our synthesis method is controllable and scalable,
allowing us to obtain graphene as large as the size of the silicon wafer over 300 millimeters in diameter,
and to control the thickness of the graphene for manufacturing production n
#Self-Cleaning Woolen Fabrics Produced in Iran Woolen products are very good sources for the growth of bacteria and microorganisms due to their protein structure,
#More efficient process to produce graphene developed by Ben-Gurion University researchers Abstract: Ben-Gurion University of the Negev (BGU) and University of Western australia researchers have developed a new process to develop few-layer graphene for use in energy storage and other material applications that is faster,
potentially scalable and surmounts some of the current graphene production limitations. Graphene is a thin atomic layer of graphite (used in pencils) with numerous properties that could be valuable in a variety of applications,
including medicine, electronics and energy. Discovered only 11 years ago, graphene is one of the strongest materials in the world, highly conductive, flexible, and transparent.
However, current methods for production currently require toxic chemicals and lengthy and cumbersome processes that result in low yield that is not scalable for commercial applications.
The new revolutionary one-step high-yield generation process is detailed in the latest issue of Carbon,
and has succeeded in synthesizing few-layer (4-5) graphene in higher yields. It involves a novel optical system (originally invented by BGU Profs.
which few-layer (and eventually single-layer graphene can be synthesized d
#Researchers boost wireless power transfer with magnetic field enhancement Wireless power transfer works by having a transmitter coil generate a magnetic field;
#Scientists print low cost radio frequency antenna with graphene ink (Nanowerk News) Scientists have moved graphene--the incredibly strong and conductive single-atom-thick sheet of carbon--a significant step along the path
Researchers from the University of Manchester, together with BGT Materials Limited, a graphene manufacturer in the United kingdom, have printed a radio frequency antenna using compressed graphene ink.
from AIP Publishing("Binder-free highly conductive graphene laminate for low cost printed radio frequency applications")."These scanning electron microscope images show the graphene ink after it was deposited
and dried (a) and after it was compressed (b). Compression makes the graphene nanoflakes more dense,
which improves the electrical conductivity of the laminate. Image: Xianjun Huang, et al.//University of Manchester) The study demonstrates that printable graphene is now ready for commercial use in low-cost radio frequency applications,
said Zhirun Hu, a researcher in the School of Electrical and Electronic engineering at the University of Manchester."
"The point is that graphene is no longer just a scientific wonder. It will bring many new applications to our daily life very soon,"added Kostya S. Novoselov, from the School of Physics and Astronomy at the University of Manchester, who coordinated the project.
Graphene Gets Inked Since graphene was isolated first and tested in 2004, researchers have striven to make practical use of its amazing electrical and mechanical properties.
One of the first commercial products manufactured from graphene was conductive ink, which can be used to print circuits and other electronic components.
Graphene ink is generally low cost and mechanically flexible advantages it has over other types of conductive ink,
such as solutions made from metal nanoparticles. To make the ink, graphene flakes are mixed with a solvent,
and sometimes a binder like ethyl cellulose is added to help the ink stick. Graphene ink with binders usually conducts electricity better than binder-free ink,
but only after the binder material, which is an insulator, is broken down in a high-heat process called annealing.
which graphene ink can be printed because the high temperatures destroy materials like paper or plastic. The University of Manchester research team
together with BGT Materials Limited, found a way to increase the conductivity of graphene ink without resorting to a binder.
and the resulting"graphene laminate"was also almost two times more conductive than previous graphene ink made with a binder.
and More The researchers tested their compressed graphene laminate by printing a graphene antenna onto a piece of paper.
"Graphene based RFID tags can significantly reduce the cost thanks to a much simpler process and lower material cost,
The University of Manchester and BGT Materials Limited team has plans to further develop graphene enabled RFID tags,
#Printing 3-D graphene structures for tissue engineering Ever since single-layer graphene burst onto the science scene in 2004,
and ultra-strong and lightweight structure, graphene has potential for many applications in electronics, energy, the environment,
Now a team of Northwestern University researchers has found a way to print three-dimensional structures with graphene nanoflakes.
The fast and efficient method could open up new opportunities for using graphene printed scaffolds regenerative engineering and other electronic or medical applications.
and her postdoctoral fellow Adam Jakus, the team developed a novel graphene-based ink that can be used to print large, robust 3-D structures."
"People have tried to print graphene before, "Shah said.""But it's been a mostly polymer composite with graphene making up less than 20 percent of the volume."
"With a volume so meager, those inks are unable to maintain many of graphene's celebrated properties.
But adding higher volumes of graphene flakes to the mix in these ink systems typically results in printed structures too brittle and fragile to manipulate.
Shah's ink is the best of both worlds. At 60-70 percent graphene, it preserves the material's unique properties,
including its electrical conductivity. And it's flexible and robust enough to print robust macroscopic structures.
the graphene flakes are mixed with a biocompatible elastomer and quickly evaporating solvents.""It's a liquid ink,
"Supported by a Google Gift and a Mccormick Research Catalyst Award, the research is described in the paper"Three-dimensional Printing Of high-Content Graphene Scaffolds for Electronic and Biomedical Applications","published in the April
An expert in biomaterials, Shah said 3-D printed graphene scaffolds could play a role in tissue engineering and regenerative medicine as well as in electronic devices.
"The printed graphene structure is also flexible and strong enough to be sutured easily to existing tissues,
and graphene's electrical conductivity most likely contributed to the scaffold's biological success."Cells conduct electricity inherently--especially neurons,
"The graphene-based ink directly follows work that Shah and her graduate student Alexandra Rutz completed earlier in the year to develop more cell-compatible, water-based, printable gels.
The new findings using a layer of one-atom-thick graphene deposited on top of a similar 2-D layer of a material called hexagonal boron nitride (hbn) are published in the journal Nano Letters("Tunable Lightatter
The hybrid material blocks light when a particular voltage is applied to the graphene while allowing a special kind of emission and propagation, called yperbolicity,
Light interaction with graphene produces particles called plasmons while light interacting with hbn produces phonons.
The properties of the graphene allow precise control over light, while hbn provides very strong confinement and guidance of the light.
says, his work represents significant progress on understanding tunable interactions of light in graphene-hbn.
The work is retty criticalfor providing the understanding needed to develop optoelectronic or photonic devices based on graphene and hbn,
#Researchers grind nanotubes to get nanoribbons (w/video) A simple way to turn carbon nanotubes into valuable graphene nanoribbons may be to grind them,
Highly conductive graphene nanoribbons, thousands of times smaller than a human hair, are finding their way into the marketplace in composite materials.
Researchers measure graphene vibrations (Nanowerk News) An international research group led by scientists at the National Institute of Standards
and Technology's (NIST) Center for Nanoscale Science and Technology has developed a method for measuring crystal vibrations in graphene.
Understanding these vibrations is a critical step toward controlling future technologies based on graphene, a one-atom thick form of carbon.
Tunneling electrons from a scanning tunneling microscope tip excites phonons in graphene. The image shows the graphene lattice with blue arrows indicating the motion direction of that carbon atoms for one of the low energy phonon modes in graphene.
Image: Wyrick/NIST) They report their findings in the June 19, 2015, issue of Physical Review Letters("Strong Asymmetric Charge Carrier Dependence in Inelastic Electron Tunneling Spectroscopy of Graphene Phonons").
"Carbon atoms in graphene sheets are arranged in a regularly repeating honeycomb-like latticea two-dimensional crystal. Like other crystals,
when enough heat or other energy is applied, the forces that bond the atoms together cause the atoms to vibrate
NIST researchers used their STM to systematically alter the number of electrons moving through their graphene device.
The team was able to map all the graphene phonons this way, and their findings agreed well with their Georgia Tech collaborators'theoretical predictions.
when we switched the graphene charge carrier from holes to electronspositive to negative charges, "says Stroscio."
The high purity graphene device was fabricated by NIST researcher Y. Zhao in the Center for Nanoscale Science and Technology's Nanofab, a national user facility available to researchers from industry, academia and government t
Image courtesy of Chongwu Zhou and Bilu Liu) The demand for a silicon material aided the discovery of graphene, a single layer of graphite
#Graphene flexes its electronic muscles Flexing graphene may be the most basic way to control its electrical properties, according to calculations by theoretical physicists at Rice university and in Russia.
and predictable in nanocones and should apply equally to other forms of graphene. The researchers discovered it may be possible to access
which the electronic properties of a sheet of graphene can be manipulated simply by twisting it a certain way.
The work will be of interest to those considering graphene elements in flexible touchscreens or memories that store bits by controlling electric dipole moments of carbon atoms
Perfect graphene an atom-thick sheet of carbon is a conductor, as its atomselectrical charges balance each other out across the plane.
But curvature in graphene compresses the electron clouds of the bonds on the concave side and stretches them on the convex side,
The researchers who published their results this month in the American Chemical Society Journal of Physical chemistry Letters discovered they could calculate the flexoelectric effect of graphene rolled into a cone of any size and length.
The researchers used density functional theory to compute dipole moments for individual atoms in a graphene lattice
and then figure out their cumulative effect They suggested their technique could be used to calculate the effect for graphene in other more complex shapes, like wrinkled sheets or distorted fullerenes,
several of which they also analyzed. hile the dipole moment is zero for flat graphene or cylindrical nanotubes,
Carbon nanotubes, seamless cylinders of graphene, do not display a total dipole moment, he said. While not zero, the vector-induced moments cancel each other out.
#Transition from 3 to 2 dimensions increases conduction Scientists from the MIPT Department of Molecular and Chemical Physics have described for the first time the behavior of electrons in a previously unstudied analogue of graphene, two-dimensional niobium telluride,
Andrei Geim and Konstantin Novoselov received the Nobel prize for their research on graphene, the most well-known among them.
For example, graphene is transparent, conducts current better than copper and has good thermal conductivity. Scientists believe that other types of two-dimensional materials may possess even more exotic properties.
#For faster, larger graphene add a liquid layer (Nanowerk News) Millimetre-sized crystals of high-quality graphene can be made in minutes instead of hours using a new scalable technique,
In just 15 minutes the method can produce large graphene crystals around 2-3 millimetres in size that it would take up to 19 hours to produce using current chemical vapour deposition (CVD) techniques in
which carbon in gas reacts with, for example, copper to form graphene. False colour image comparing graphene created on a pristine platinum surface with graphene created on the liquid layer of platinum silicide.
Image: University of Oxford) Graphene promises to be a'wonder material'for building new technologies because of its combination of strength, flexibility, electrical properties,
and chemical resistance. But this promise will only be realised if it can be produced cost-effectively on a commercial scale.
so that carbon atoms in methane gas brushing the surface are inclined more to form large flakes of graphene.
A report of the research is published in the journal Nature Communications"Rapid epitaxy-free graphene synthesis on silicidated polycrystalline platinum".(
"Innovative substrate engineering for high quality 2d nanomaterials")'Not only can we make millimetre-sized graphene flakes in minutes
but this graphene is of a comparable quality to anything other methods are able to produce,
'Because it is allowed to grow naturally in single graphene crystals there are none of the grain boundaries that can adversely affect the mechanical and electrical properties of the material.'
and larger-scale graphene production for applications where very high quality graphene is needed.''Size-wise the new approach compares favourably with the common'Scotch tape method,'in
which a piece of tape is used to peel graphene fragments off a chunk of graphite,
But with the liquid layer of platinum silicide the researchers show that graphene crystals of 2-3 millimetres can be produced in minutes.
Out of all the techniques currently used to make different types of graphene CVD is the most promising for scaling up into a cost-effective industrial process.
with a thicker liquid layer to insulate it the graphene might not have to be removed from the substrate before it can be used-a costly
'This is a proof of principle study that shows that high-quality graphene, in the form of a single layer of carbon atoms, can be made to the size
'Of course a great deal more work is required before we get graphene technology, but we're now on the cusp of seeing this material make the leap from the laboratory to a manufacturing setting,
and scale up this technique to produce flakes of graphene in large wafer-sized sheets. This invention adds to the growing patent portfolio of nanomaterials and their production technologies from Professor Nicole Grobert's Nanomaterials By design Group.
#An easy, scalable and direct method for synthesizing graphene in silicon microelectronics (Nanowerk News) In the last decade,
graphene has been studied intensively for its unique optical, mechanical, electrical and structural properties. The one-atom-thick carbon sheets could revolutionize the way electronic devices are manufactured
As a potential contact electrode and interconnection material, wafer-scale graphene could be an essential component in microelectronic circuits,
but most graphene fabrication methods are not compatible with silicon microelectronics, thus blocking graphene's leap from potential wonder material to actual profit-maker.
Now researchers from Korea University in Seoul, have developed an easy and microelectronics-compatible method to grow graphene
and have synthesized successfully wafer-scale (four inches in diameter), high-quality, multi-layer graphene on silicon substrates.
The method is based on an ion implantation technique, a process in which ions are accelerated under an electrical field and smashed into a semiconductor.
In a paper published this week in the journal Applied Physics Letters("Wafer-scale synthesis of multi-layer graphene by high-temperature carbon ion implantation"),from AIP Publishing
which takes graphene a step closer to commercial applications in silicon microelectronics. Wafer-scale (4 inch in diameter) synthesis of multi-layer graphene using high-temperature carbon ion implantation on nickel/Sio2/silicon.
Image: J. Kim/Korea University, Korea)" For integrating graphene into advanced silicon microelectronics, large-area graphene free of wrinkles, tears and residues must be deposited on silicon wafers at low temperatures,
which cannot be achieved with conventional graphene synthesis techniques as they often require high temperatures, "said Jihyun Kim, the team leader and a professor in the Department of Chemical and Biological engineering at Korea University."
"Our work shows that the carbon ion implantation technique has great potential for the direct synthesis of wafer-scale graphene for integrated circuit technologies."
"Discovered just over a decade ago, graphene is considered now the thinnest, lightest and strongest material in the world.
Graphene is completely flexible and transparent while being inexpensive and nontoxic, and it can conduct electricity as well as copper,
carrying electrons with almost no resistance even at room temperature, a property known as ballistic transport. Graphene's unique optical, mechanical and electrical properties have lead to the one-atom-thick form of carbon being heralded as the next generation material for faster, smaller, cheaper and less power-hungry electronics."
"In silicon microelectronics, graphene is a potential contact electrode and an interconnection material linking semiconductor devices to form the desired electrical circuits,
"said Kim.""This renders high processing temperature undesirable, as temperature-induced damage, strains, metal spiking
"Thus, although the conventional graphene fabrication method of chemical vapor deposition is used widely for the large-area synthesis of graphene on copper and nickel films,
000 degrees Celsius and a subsequent transfer process of the graphene from the metallic film to the silicon."
"The transferred graphene on the target substrate often contains cracks, wrinkles and contaminants,"said Kim."
"Thus, we are motivated to develop a transfer-free method to directly synthesize high quality, multilayer graphene in silicon microelectronics."
The nickel layer, with high carbon solubility, is used as a catalyst for graphene synthesis. The process is followed then by high temperature activation annealing (about 600 to 900 degrees Celsius) to form a honeycomb lattice of carbon atoms, a typical microscopic structure of graphene.
Kim explained that the activation annealing temperature could be lowered by performing the ion implantation at an elevated temperature.
multi-layer graphene by varying the ambient pressure, ambient gas, temperature and time during the treatment.
as the graphene layer thickness can be determined precisely by controlling the dose of carbon ion implantation.""Our synthesis method is controllable and scalable,
allowing us to obtain graphene as large as the size of the silicon wafer over 300 millimeters in diameter,
and to control the thickness of the graphene for manufacturing production n
#Degrading BPA with visible light and a new hybrid nanoparticle photocatalyst Over the course of the last half century, BPA has gone from miracle to menace.
Their findings, published this week in the journal APL Materials("Reduced graphene oxide and Ag wrapped Tio2 photocatalyst for enhanced visible light photocatalysis),
Then, they wrapped the Ag/Tio2 nanoparticles in sheets of reduced graphene oxide (RGO), a thin layer of carbon atoms arranged in a honeycomb pattern.
Toward Developing High-performance Graphene-Based Architectures for Energy storage devices"."The conundrum researchers have faced in developing miniature energy storage devices,
graphene, a conductive polymer and carbon nanotubes, which are atom-thick latticelike networks of carbon formed into cylinders.
Graphene, made from single atom-thick layers of graphite, was a suitable candidate due its electronic performance
The graphene in liquid form was mixed with the conductive polymer and reduced to solid and the carbon nanotubes carefully inserted between the graphene layers to form a self-assembled flat-packed,
wafer-thin supercapacitor material. he real challenge was how to assemble these three components into a single structure with the best use of the space available,
which enabled natural chemical interactions to prevent the graphene layers clumping together. The result was a 3d shape with, thanks to the carbon nanotubes, a massive surface area, excellent charge capacity that is also foldable.
or sophisticated equipment. ur graphene-based flexible composite is highly conductive, lightweight, is able to fold like a roll
if a GST layer were sandwiched between two thin graphite layers or even between two layers of graphene.
The sheets of cross-linked carbon atoms of which graphene is comprised fulfil the necessary requirements. The physicists in Ralph Ernstorfers group now want to experiment further with precisely these sandwiches of different materials.
Thats what Northeastern physicists Swastik Kar and Srinivas Sridhar found during their four-year project to modify graphene, a stronger-than-steel infinitesimally thin lattice of tightly packed carbon atoms.
the addition of boron and nitrogen to graphenes carbon to connote the conductivity necessary to produce an electrical insulator.
including those that are made with graphene electrodes a
#Nivolumab helps fight Cancerous Lung Tumors A trial has suggested that a therapy for lung cancer has the ability to double the life expectancy in patients.
#Graphene Filaments Provide Tunable On-Chip Light source Graphene Filaments Provide Tunable On-Chip Light Sourcenew YORK, June 15,
Researchers from the U s. and South korea collaborated to develop an on-chip visible light source using filaments made of graphene.
They attached small strips of graphene to metal electrodes, suspended the strips above a silicon substrate,
and graphene-based on-chip optical communications.""Schematic illustration of electrically biased suspended graphene and light emission from the center of the suspended graphene.
Images courtesy of Young Duck Kim/Columbia Engineering. The ability to create light in small structures on the surface of a microchip is a crucial step towards the development of fully integrated photonic circuits.
The ability of graphene to achieve such high temperatures without melting the substrate or the metal electrodes is due to another interesting property:
graphene becomes a much poorer conductor of heat. High temperatures are confined to a small ot spotin the center."
"At the highest temperatures, the electron temperature is much higher than that of acoustic vibrational modes of the graphene lattice,
"These unique thermal properties allow us to heat the suspended graphene to up to half of the temperature of the sun
as compared to graphene on a solid substrate.""By measuring the spectrum of the light emitted from the graphene,
the team was able to show that graphene was reaching temperatures of above 2500°Celsius,
hot enough to glow brightly.""The visible light from atomically thin graphene is so intense that it is visible even to the naked eye,
without any additional magnification,"said Young Duck Kim, a postdoctoral research scientist at Columbia. An optical image, top,
and micrograph, bottom, of bright, visible light emission from suspended graphene. The spectrum of the emitted light showed peaks at specific wavelengths,
which the team discovered was due to interference between the light emitted directly from the graphene
and light reflecting off the silicon substrate and passing back through the graphene.""This is only possible
because graphene is transparent, unlike any conventional filament, and allows us to tune the emission spectrum by changing the distance to the substrate,
The team also demonstrated the scalability of their technique by realizing large-scale arrays of graphene light emitters grown with a chemical vapor deposition (CVD) process."
but using it in its pure form graphene and at its ultimate size limit one atom thick,
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