Graphene Nanoribbons Boost Electronics

Graphene, an atom-thick material with extraordinary properties, is a promising candidate for the next generation of dramatically faster, more energy-efficient electronics. However, scientists have struggled to fabricate the material into ultra-narrow strips, called nanoribbons, that could enable the use of graphene in high-performance semiconductor electronics.

Now, University of Wisconsin-Madison engineers have discovered a way to grow graphene nanoribbons with desirable semiconducting properties directly on a conventional germanium semiconductor wafer. This advance could allow manufacturers to easily use graphene nanoribbons in hybrid integrated circuits, which promise to significantly boost the performance of next-generation electronic devices. The technology could also have specific uses in industrial and military applications, such as sensors that detect specific chemical and biological species and photonic devices that manipulate light.

In a paper published Aug. 10 in the journal Nature Communications, Michael Arnold, an associate professor of materials science and engineering at UW-Madison, Ph.D. student Robert Jacobberger, and their collaborators describe their new approach to producing graphene nanoribbons. Importantly, their technique can easily be scaled for mass production and is compatible with the prevailing infrastructure used in semiconductor processing.

graphene nanoribbonsProgressively zoomed-in images of graphene nanoribbons grown on germanium. The ribbons automatically align perpendicularly and naturally grow in what is known as the armchair edge configuration.



Graphene nanoribbons that can be grown directly on the surface of a semiconductor like germanium are more compatible with planar processing that’s used in the semiconductor industry, and so there would be less of a barrier to integrating these really excellent materials into electronics in the future,” Arnold says.


Ultrathin Electronics At Nano Scale

Semiconductors, metals and insulators must be integrated to make the transistors that are the electronic building blocks of your smartphone, computer and other microchip-enabled devices. Today’s transistors are miniscule—a mere 10 nanometers wide—and formed from three-dimensional (3D) crystals.

But a disruptive new technology looms that uses two-dimensional (2D) crystals, just 1 nanometer thick, to enable ultrathin electronics. Scientists worldwide are investigating 2D crystals made from common layered materials to constrain electron transport within just two dimensions. Researchers had previously found ways to lithographically pattern single layers of carbon atoms called graphene into ribbon-like “wires” complete with insulation provided by a similar layer of boron nitride. But until now they have lacked synthesis and processing methods to lithographically pattern junctions between two different semiconductors within a single nanometer-thick layer to form transistors, the building blocks of ultrathin electronic devices. Now for the first time, researchers at the Department of Energy’s Oak Ridge National Laboratory (ONRL) have combined a novel synthesis process with commercial electron-beam lithography techniques to produce arrays of semiconductor junctions in arbitrary patterns within a single, nanometer-thick semiconductor crystal.

scalable arrays of semiconductor junctions

We can literally make any kind of pattern that we want,” said Masoud Mahjouri-Samani, who co-led the study with David Geohegan. Geohegan, head of ORNL’s Nanomaterials Synthesis and Functional Assembly Group at the Center for Nanophase Materials Sciences, is the principal investigator of a Department of Energy basic science project focusing on the growth mechanisms and controlled synthesis of nanomaterials.
Millions of 2D building blocks with numerous patterns may be made concurrently, Mahjouri-Samani added. In the future, it might be possible to produce different patterns on the top and bottom of a sheet.


How To Make Batteries Last Five Times Longer

Lithium-ion batteries have enabled many of today’s electronics, from portable gadgets to electric cars. But much to the frustration of consumers, none of these batteries last long without a recharge. Now scientists report in the journal ACS Nano the development of a new, “green” way to boost the performance of these batteries — with a material derived from silk.
silk to boost batteryChuanbao Cao from the Beijing Institute of Technology (China) note that carbon is a key component in commercial Li-ion energy storage devices including batteries and supercapacitors. Most commonly, graphite fills that role, but it has a limited energy capacity.

The Cao’s team found a way to process natural silk to create carbon-based nanosheets that could potentially be used in energy storage devices. Their material stores five times more lithium than graphite can — a capacity that is critical to improving battery performance. It also worked for over 10,000 cycles with only a 9 percent loss in stability. The researchers successfully incorporated their material in prototype batteries and supercapacitors in a one-step method that could easily be scaled up.

Cloth That Produces Electricity

Fully flexible, foldable nanopatterned wearable triboelectric nanogenerator (WTNG) with high power-generating performance and mechanical robustness have been designed by researchers from the SKKU Advanced Institute of Nanotechnology (SAINT) (Korea). Triboelectric is an electrical charge produced by friction between two objects that are nonconductive. Very high voltage and current outputs with an average value of 170 V were obtained from a four-layer-stacked WTNG. The researchers created a novel tribo electric nano generator fabric out of a silvery textile coated with nanorods and a silicon-based organic material.
When they stacked four pieces of the cloth together and pushed down on the material, it captured the energy generated from the pressure. The material immediately pumped out that energy, which was used to power light-emitting diodes, a liquid crystal display and a vehicle’s keyless entry remote. The cloth worked for more than 12,000 cycles.


How To Boost Electric Vehicle Batteries

Researchers from the Professor Mihri Ozkan lab at the University of California, Riverside’s Bourns College of Engineering have developed a novel paper-like material for lithium-ion batteries. It has the potential to boost by several times the specific energy, or amount of energy that can be delivered per unit weight of the battery.
This paper-like material is composed of sponge-like silicon nanofibers more than 100 times thinner than human hair. It could be used in batteries for electric vehicles and personal electronics.

electric carThe problem with silicon is that is suffers from significant volume expansion, which can quickly degrade the battery. The silicon nanofiber structure created in the Ozkan’s labs circumvents this issue and allows the battery to be cycled hundreds of times without significant degradation. This technology also solves a problem that has plagued free-standing, or binderless, electrodes for years: scalability. Free-standing materials grown using chemical vapor deposition, such as carbon nanotubes or silicon nanowires, can only be produced in very small quantities (micrograms). However, the team was able to produce several grams of silicon nanofibers at a time even at the lab scale.

The nanofibers were produced using a technique known as electrospinning, whereby 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate (TEOS), a chemical compound frequently used in the semiconductor industry. The nanofibers are then exposed to magnesium vapor to produce the sponge-like silicon fiber structure.

The findings were just published in the journal Nature Scientific Reports.

Ultra Bendable Electronics

Electronic devices have shrunk rapidly in the past decades, but most remain as stiff as the same sort of devices were in the 1950s — a drawback if you want to wrap your phone around your wrist when you go for a jog or fold your computer to fit in a pocket. Researchers from South Korea have taken a new step toward more bendable devices by manufacturing a thin film that keeps its useful electric and magnetic properties even when highly curved.

nanoparticles od bismuth
This electron microscope image shows tiny nanoparticles of bismuth ferrite embedded in a polymer film. The film enhances the unique electric and magnetic properties of bismuth ferrite and preserves these properties even when bent
Bulk bismuth ferrite has crucial problems for some applications, such as a high leakage current which hinders the strong electric properties,” said YoungPak Lee, a professor at Hanyang University in Seoul, South Korea. Mixing nanoparticles of bismuth ferrite into a polymer improved the current-leakage problem, he said, and also gave the film flexible, stretchable properties.

Flexible multiferrorics could enable new wearable devices such as health monitoring equipment or virtual reality attire, Lee said. The multiferroric materials could be used in high-density, energy efficient memory and switches in such devices, he said.
The researchers describe the film in a paper published in the journal Applied Physics Letters, from AIP Publishing.


Medical Nanorobots

Researchers from the Institute of General Physics, the Institute of Bioorganic Chemistry (Russia, Academy of Sciences) and MIPT have made an important step towards creating medical nanorobots. They discovered a way of enabling nano– and microparticles to produce logical calculations using a variety of biochemical reactions.
biological nanorobotsThe scientists draw on the idea of computing using biomolecules. In electronic circuits, for instance, logical connectives use current or voltage (if there is voltage, the result is 1, if there is none, it’s 0). In biochemical systems, the result can a given substance. For example, modern bioengineering techniques allow for making a cell illuminate with different colors or even programming it to die, linking the initiation of apoptosis to the result of binary operations.

Scientists say logical operations inside cells to be a way of controlling biological processes and creating nano-robots, which can deliver drugs on schedule. Calculations using biomolecules inside cells, a.k.a. biocomputing, are a very promising and rapidly developing branch of science, according to the leading author of the study, Maxim Nikitin, a 2010 graduate of MIPT’s Department of Biological and Medical Physics. Biocomputing uses natural cellular mechanisms.

The study paves the way for a number of biomedical technologies and differs significantly from previous works in biocomputing binary operations in DNA, RNA and proteins for over a decade now, but Maxim Nikitin and his colleagues were the first to propose and experimentally confirm a method to transform almost any type of nanoparticle or microparticle into autonomous biocomputing structures that are capable of implementing a functionally complete set of Boolean logic gates (YES, NOT, AND and OR) and binding to a target (such as a cell) as result of a computation.

The prefix “nano” in this case is not a fad or a mere formality. A decrease in particle size sometimes leads to drastic changes in the physical and chemical properties of a substance. The smaller the size, the greater the reactivity; very small semiconductor particles, for example, may produce fluorescent light. The new research project used nanoparticles (i.e. particles of 100 nm) and microparticles (3000 nm or 3 micrometers).

The new work was published on the website of the journal Nature Nanotechnology.

Computer: Nano Optical Cables To Replace Copper

Electrical engineers design nano-optical cables that could replace copper wiring on computer chips. The invention of fibre optics revolutionized the way we share information, allowing us to transmit data at volumes and speeds we’d only previously dreamed of. Now, electrical engineering researchers at the University of Alberta are breaking another barrier, designing nano-optical cables small enough to replace the copper wiring on computer chips. This could result in radical increases in computing speeds and reduced energy use by electronic devices. A new step towards the nanocomputer era.

We’re already transmitting data from continent to continent using fibre optics, but the killer application is using this inside chips for interconnect—that is the Holy Grail,” says Zubin Jacob, an electrical engineering professosr leading the research. “What we’ve done is come up with a fundamentally new way of confining light to the nano scale.
At present, the diameter of fibre optic cables is limited to about one thousandth of a millimetre. Cables designed by graduate student Saman Jahani and Jacob are 10 times smaller—small enough to replace copper wiring still used on computer chips. (To put that into perspective, a dime is about one millimetre thick.)


How To Embed Semiconductor Crystals Into A Nanowire

Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany), the Vienna University of Technology (Austria) and the Maria Curie-Skłodowska University Lublin (Poland) have succeeded in embedding nearly perfect semiconductor crystals into a silicon nanowire. With this new method of producing hybrid nanowires, very fast and multi-functional processing units can be accommodated on a single chip (nanocomputer) in the future.
Nano-optoelectronics are considered the cornerstone of future chip technology. Scientists have now come a step closer to both these targets: they integrated compound semiconductor crystals made of indium arsenide (InAs) into silicon nanowires, which are ideally suited for constructing increasingly compact chips.

This integration of crystals was the greatest obstacle for such “hetero-nanowires” until now: beyond the nanometer range, crystal lattice mismatch always led to numerous defects. The researchers have now managed a near-perfect production and embedding of the InAs crystals into the nanowires for the first time.
iridium arsenide

Indium arsenide (green-cyan) is perfectly integrated into the silicon nanowire (blue). (Energy-dispersive X-ray spectroscopy). The energy-dispersive X-ray spectroscopy (colored pricture) was performed at École polytechnique fédérale de Lausanne, Switzerland.

The research results will be published in the journal Nano Research.


Electronics Enter The Nanocomputer Age

An UAlberta research team is developing atom-scale, ultra-low-power computing devices to replace transistor circuits. In the drive to get small, Robert Wolkow and his lab at the University of Alberta are taking giant steps forward. The digital age has resulted in a succession of smaller, cleaner and less power-hungry technologies since the days the personal computer fit atop a desk, replacing mainframe models that once filled entire rooms. Desktop PCs have since given way to smaller and smaller laptops, smartphones and devices that most of us carry around in our pockets. But as Wolkow points out, this technological shrinkage can only go so far when using traditional transistor-based integrated circuits. That’s why he and his research team are aiming to build entirely new technologies at the atomic scale.
Our ultimate goal is to make ultra-low-power electronics because that’s what is most demanded by the world right now,” said Wolkow, the iCORE Chair in Nanoscale Information and Communications Technology in the Faculty of Science. “We are approaching some fundamental limits that will stop the 30-year-long drive to make things faster, cheaper, better and smaller; this will come to an end soon. “An entirely new method of computing will be necessary.”

Wolkow and his team in the U of A’s physics department and the National Institute for Nanotechnology are working to engineer atomically precise technologies that have practical, real-world applications. His lab already made its way into the Guinness Book of World Records for inventing the world’s sharpest object—a microscope tip just one atom wide at its end.


Sand-based Lithium Ion Batteries That Outperform Standard by 3 times

Researchers at the University of California, Riverside’s Bourns College of Engineering have created a lithium ion battery that outperforms the current industry standard by three times. The key material: sand. Yes, sand.

This is the holy grail – a low cost, non-toxic, environmentally friendly way to produce high performance lithium ion battery anodes,” said Zachary Favors, a graduate student working with Cengiz and Mihri Ozkan, both engineering professors at UC Riverside.
The idea came to Favors six months ago. He was relaxing on the beach after surfing in San Clemente, Calif. when he picked up some sand, took a close look at it and saw it was made up primarily of quartz, or silicon dioxide.

His research is centered on building better lithium ion batteries, primarily for personal electronics and electric vehicles. He is focused on the anode, or negative side of the battery. Graphite is the current standard material for the anode, but as electronics have become more powerful graphite’s ability to be improved has been virtually tapped out.
Researchers are now focused on using silicon at the nanoscale, or billionths of a meter, level as a replacement for graphite. The problem with nanoscale silicon is that it degrades quickly and is hard to produce in large quantities.
Findings have been published in in the journal Nature Scientific Reports.

2016: The End Of Cables, A Completely Wireless PC

Intel‘s Skylake, which is the company’s post-Broadwell next-generation platform, will allow the PC maker to eliminate the need for any cables by 2016. Kirk Skaugen, Intel senior Vice-President , has demonstrated at Taipei’s Computex show wireless capabilities for docking, charging and display, which are the last functions for the PC that still require cables. A completely wireless PC has long been desired, but the idea has faced much difficulty because of the need for connecting cables by PC peripherals, along with the system’s need for power.

Intel is looking to use WiGig, a new protocol that can deliver speeds of up to 7 Gbps, to provide short-range docking for display and connectivity The WiGig instantly connects screens and other peripherals when a tablet or laptop appears within the device’s range, and also instantly disconnects as the tablet or laptop is moved away. Users can project what’s on their computer screen to other computer screens wirelessly.

For power, on the other hand, Intel is looking at using Rezence, which Skaugen demonstrated. Rezence is a charging technology that uses magnetic resonance (The phenomenon of absorption of certain frequencies of radio and microwave radiation by atoms placed in a magnetic field. The pattern of absorption reveals molecular structure). The technology is promoted by Intel-backed group Alliance 4 Wireless Power. It can be placed underneath the surface of a table, with the system’s magnetic resonance able to charge devices through even 2 inches of wood. Also, unlike inductive chargers that can only charge one device at a time, magnetic resonance chargers can charge several devices all at once.

The system was also demonstrated by Skaugen at Computex, using a table installed with Rezence to charge a mobile phone, a headset, a laptop and a tablet simultaneously. Skaugen also announced new member companies of the A4WP, which includes Lenovo, Fujitsu, Dell, Panasonic and Logitech, to work with already partners Toshiba and Asus.

Let’s remind that the company Apple has dabbled into magnetic resonance charging technology in the past, filing a patent for the technology.