Posts belonging to Category electronics

Ultra-fast Data Processing At Nanoscale

Advancement in nanoelectronics, which is the use of nanotechnology in electronic components, has been fueled by the ever-increasing need to shrink the size of electronic devices like nanocomputers in a bid to produce smaller, faster and smarter gadgets such as computers, memory storage devices, displays and medical diagnostic tools.

While most advanced electronic devices are powered by photonics – which involves the use of photons to transmit informationphotonic elements are usually large in size and this greatly limits their use in many advanced nanoelectronics systems. Plasmons, which are waves of electrons that move along the surface of a metal after it is struck by photons, holds great promise for disruptive technologies in nanoelectronics. They are comparable to photons in terms of speed (they also travel with the speed of light), and they are much smaller. This unique property of plasmons makes them ideal for integration with nanoelectronics. However, earlier attempts to harness plasmons as information carriers had little success.

Addressing this technological gap, a research team from the National University of Singapore (NUS) has recently invented a novel “converter” that can harness the speed and small size of plasmons for high frequency data processing and transmission in nanoelectronics.

This innovative transducer can directly convert electrical signals into plasmonic signals, and vice versa, in a single step. By bridging plasmonics and nanoscale electronics, we can potentially make chips run faster and reduce power losses. Our plasmonic-electronic transducer is about 10,000 times smaller than optical elements. We believe it can be readily integrated into existing technologies and can potentially be used in a wide range of applications in the future,” explained Associate Professor Christian Nijhuis from the Department of Chemistry at the NUS Faculty of Science, who is the leader of the research team behind this breakthrough.

This novel discovery was first reported in the journal Nature Photonics.


How To Extract Hydrogen Fuel from Seawater

It’s possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF researcher Yang Yang from the University of Central Florida (UCF)  has come up with a new hybrid nanomaterial that harnesses solar energy and uses it to generate hydrogen from seawater more cheaply and efficiently than current materials. The breakthrough could someday lead to a new source of the clean-burning fuel, ease demand for fossil fuels and boost the economy of Florida, where sunshine and seawater are abundant. Yang, an assistant professor with joint appointments in the University of Central Florida’s NanoScience Technology Center and the Department of Materials Science and Engineering, has been working on solar hydrogen splitting for nearly 10 years.

It’s done using a photocatalyst – a material that spurs a chemical reaction using energy from light. When he began his research, Yang focused on using solar energy to extract hydrogen from purified water. It’s a much more difficulty task with seawater; the photocatalysts needed aren’t durable enough to handle its biomass and corrosive salt.

We’ve opened a new window to splitting real water, not just purified water in a lab,” Yang said. “This really works well in seawater.”

As reported in the journal Energy & Environmental Science, Yang and his research team have developed a new catalyst that’s able to not only harvest a much broader spectrum of light than other materials, but also stand up to the harsh conditions found in seawater.



How To Forge Graphene In 3D Shape

The wonder material graphene gets many of its handy quirks from the fact that it exists in two dimensions, as a sheet of carbon only one atom thick. But to actually make use of it in practical applications, it usually needs to be converted into a 3D form. Now, researchers have developed a new and relatively simple way to do just that, using lasers to “forge” a three-dimensional pyramid out of graphene.

This isn’t the first time graphene has been given an extra dimension. In 2015, researchers from the University of Illinois molded graphene into 3D structures by layering it onto shaped substrates, and early this year MIT scientists found that tubes of the stuff could be shaped into 3D coral-like structures 10 times stronger than steel but just five percent as dense. Rice University researchers have also recently made graphene foam and reinforced it with carbon nanotubes.

But this new technique, developed by researchers in Finland and Taiwan, might be an easier and faster method to make 3D graphene. By focusing a laser onto a fine point on a 2D graphene lattice, the graphene at that spot is irradiated and bulges outwards. A variety of three-dimensional shapes can be made by writing patterns with the laser spot, with the height of the shape controlled by adjusting the irradiation dose at each particular point.

The team illustrated that technique by deforming a sheet of graphene into a 3D pyramid, standing 60 nm high. That sounds pretty tiny, but it’s 200 times taller than the graphene sheet itself.

We call this technique optical forging, since the process resembles forging metals into 3D shapes with a hammer,” says Mika Pettersson, co-author of the study. “In our case, a laser beam is the hammer that forges graphene into 3D shapes. The beauty of the technique is that it’s fast and easy to use; it doesn’t require any additional chemicals or processing. Despite the simplicity of the technique, we were very surprised initially when we observed that the laser beam induced such substantial changes on graphene. It took a while to understand what was happening.”

The researchers initially assumed that the laser had “doped” the graphene, introducing impurities into the material, but after further examination they found that wasn’t the case.

When we first examined the irradiated graphene, we were expecting to find traces of chemical species incorporated into the graphene, but we couldn’t find any,” comments Wei Yen Woon, co-author of the study. “After some more careful inspections, we concluded that it must be purely structural defects, rather than chemical doping, that are responsible for such dramatic changes on graphene.

The scientists explain that the optically forged graphene is structurally sound, highlighting its potential for building 3D architectures out of the material for a wide range of applications. In this form, the graphene has different electronic and optical properties from its 2D counterpart.

The research was published in the journal Nano Letters.

Source: Academy of Finland

Graphene, Not Glass, Is The Key To Better Optics

A lens just a billionth of a metre thick could transform phone cameras. Researchers at Swinburne University in Melbourne, Australia, have created ultra-thin lenses that cap an optical fibre, and can produce images with the quality and sharpness of much larger glass lenses.

Compared with current lenses, our graphene lens only needs one film to achieve the same resolution,” says Professor Baohua Jia, a research leader at Swinburne’s Centre for Micro-Photonics. “In the future, mobile phones could be much thinner, without having to sacrifice the quality of their cameras. Our lens also allows infrared light to pass through, which glass lenses don’t.”

Producing graphene can be costly and challenging, so Baohua and her colleagues used a laser to pattern layers of graphene oxide (graphene combined with oxygen). By then removing the oxygen, they produced low-cost, patterned films of graphene, a thousand times thinner than a human hair. “By patterning the graphene oxide film in this way, its optical and electrical properties can be altered, which allowed us to place them in different devices,” she says.

Warm objects give off infrared light, so mobile phones with graphene lenses could be used to scan for hotspots in the human body and help in the early identification of diseases like breast cancer. By attaching the lens to a fibre optic tip, endoscopes — instruments that are currently several millimetres wide—could be made a million times smaller. The team is also investigating graphene’s amazing properties for their potential use as supercapacitors, capable of storing very large amounts of energy, which could replace conventional batteries.

Baohua’s work on graphene lenses was published in Nature Communications.


Flying Electric Planes Between London And Paris

EasyJet could be flying planes powered by batteries rather than petroleum to destinations including Paris and Amsterdam within a decade. The UK carrier has formed a partnership with US firm Wright Electric, which is developing a battery-propelled aircraft for flights under two hoursEasyJet said the move would enable battery-powered aircraft to travel short-haul routes such as London to Paris and Amsterdam, and Edinburgh to Bristol. Wright Electric is aiming for an aircraft range of 335 miles, which would cover the journeys of about a fifth of passengers flown by easyJet.

Carolyn McCall, easyJet’s chief executive, said the aerospace industry would follow the lead of the automotive industry in developing electric engines that would cut emissions and noise.

For the first time in my career I can envisage a future without jet fuel and we are excited to be part of it,” she said. “It is now more a matter of when, not if, a short-haul electric plane will fly.”

The company said it was the next step in making the airline less harmful for the environment, after cutting carbon emissions per passenger kilometre by 31% between 2000 and 2016. Wright Electric claims that electric planes will be 50% quieter and 10% cheaper for airlines to buy and operate, with the cost saving potentially passed on to passengers. The US firm said its goal was for every short flight to be electric within 20 years. It has already built a two-seater prototype and is working towards a fully electric plane within a decade. The next step is to scale-up the technology to a 10-seater aircraft, and eventually to build a single aisle, short haul commercial plane, with the capacity to carry at least 120 passengers.


Renewable Fuel From Water

Physicists at Lancaster University (in UK) are developing methods of creating renewable fuel from water using quantum technologyRenewable hydrogen can already be produced by photoelectrolysis where solar power is used to split water molecules into oxygen and hydrogen. But, despite significant research effort over the past four decades, fundamental problems remain before this can be adopted commercially due to inefficiency and lack of cost-effectivenessDr Manus Hayne  from the Department of Physics said: “For research to progress, innovation in both materials development and device design is clearly needed.

The Lancaster study, which formed part of the PhD research of Dr Sam Harrison, and is published in Scientific Reports, provides the basis for further experimental work into the solar production of hydrogen as a renewable fuel. It demonstrates that the novel use of nanostructures could increase the maximum photovoltage generated in a photoelectrochemical cell, increasing the productivity of splitting water molecules.

To the authors’ best knowledge, this system has never been investigated either theoretically or experimentally, and there is huge scope for further work to expand upon the results presented here,” said Dr Haynes. “Fossil-fuel combustion releases carbon dioxide into the atmosphere, causing global climate change, and there is only a finite amount of them available for extraction. We clearly need to transition to a renewable and low-greenhouse-gas energy infrastructure, and renewable hydrogen is expected to play an important role.

Fossil fuels accounted for almost 90% of energy consumption in 2015, with absolute demand still increasing due to a growing global population and increasing industrialisationPhotovoltaic solar cells are currently used to convert sunlight directly into electricity but solar hydrogen has the advantage that it is easily stored, so it can be used as and when needed. Hydrogen is also very flexible, making it highly advantageous  for remote communities. It can be converted to electricity in a fuel cell, or burnt in a boiler or cooker just like natural gas. It can even be used to fuel aircraft.


Computer Reads Body Language

Researchers at Carnegie Mellon University‘s Robotics Institute have enabled a computer to understand body poses and movements of multiple people from video in real time — including, for the first time, the pose of each individual’s hands and fingers. This new method was developed with the help of the Panoptic Studio — a two-story dome embedded with 500 video cameras — and the insights gained from experiments in that facility now make it possible to detect the pose of a group of people using a single camera and a laptop computer.

Yaser Sheikh, associate professor of robotics, said these methods for tracking 2-D human form and motion open up new ways for people and machines to interact with each other and for people to use machines to better understand the world around them. The ability to recognize hand poses, for instance, will make it possible for people to interact with computers in new and more natural ways, such as communicating with computers simply by pointing at things.

Detecting the nuances of nonverbal communication between individuals will allow robots to serve in social spaces, allowing robots to perceive what people around them are doing, what moods they are in and whether they can be interrupted. A self-driving car could get an early warning that a pedestrian is about to step into the street by monitoring body language. Enabling machines to understand human behavior also could enable new approaches to behavioral diagnosis and rehabilitation, for conditions such as autism, dyslexia and depression.


We communicate almost as much with the movement of our bodies as we do with our voice,” Sheikh said. “But computers are more or less blind to it.”

In sports analytics, real-time pose detection will make it possible for computers to track not only the position of each player on the field of play, as is now the case, but to know what players are doing with their arms, legs and heads at each point in time. The methods can be used for live events or applied to existing videos.

To encourage more research and applications, the researchers have released their computer code for both multi-person and hand pose estimation. It is being widely used by research groups, and more than 20 commercial groups, including automotive companies, have expressed interest in licensing the technology, Sheikh said.

Sheikh and his colleagues have presented reports on their multi-person and hand pose detection methods at CVPR 2017, the Computer Vision and Pattern Recognition Conference  in Honolulu.


Very Fast Magnetic Data Storage

For almost seventy years now, magnetic tapes and hard disks have been used for data storage in computers. In spite of many new technologies that have been developed in the meantime, the controlled magnetization of a data storage medium remains the first choice for archiving information because of its longevity and low price. As a means of realizing random access memories (RAMs), however, which are used as the main memory for processing data in computers, magnetic storage technologies were long considered inadequate. That is mainly due to its low writing speed and relatively high energy consumption.

In 1956, IBM introduced the first magnetic hard disc, the RAMAC. ETH researchers have now tested a novel magnetic writing technology that could soon be used in the main memories of modern computers

Pietro Gambardella, Professor at the Department of Materials of the Eidgenössische Technische Hochschule Zürich (ETHZ, Switzerland), and his colleagues, together with colleagues at the Physics Department and at the Paul Scherrer Institute (PSI), have now shown that using a novel technique, magnetic storage can still be achieved very fast and without wasting energy.

In 2011, Gambardella and his colleagues already demonstrated a technique that could do just that: An electric current passing through a specially coated semiconductor film inverted the magnetization in a tiny metal dot. This is made possible by a physical effect called spin-orbit-torque. In this effect, a current flowing in a conductor leads to an accumulation of electrons with opposite magnetic moment (spins) at the edges of the conductor. The electron spins, in turn, create a magnetic field that causes the atoms in a nearby magnetic material to change the orientation of their magnetic moments. In a new study the scientists have now investigated how this process works in detail and how fast it is.

The results were recently published in the scientific journal Nature Nanotechnology.


Robots With The Sense Of Touch

A team of researchers from the University of Houston (UH) has reported a breakthrough in stretchable electronics that can serve as an artificial skin, allowing a robotic hand to sense the difference between hot and cold, while also offering advantages for a wide range of biomedical devices.

Cunjiang Yu, Bill D. Cook Assistant Professor of mechanical engineering and lead author for the paper, said the work is the first to create a semiconductor in a rubber composite format, designed to allow the electronic components to retain functionality even after the material is stretched by 50 percent. The semiconductor in rubber composite format enables stretchability without any special mechanical structure. Yu noted that traditional semiconductors are brittle and using them in otherwise stretchable materials has required a complicated system of mechanical accommodations. “That’s both more complex and less stable than the new discovery, as well as more expensive.”

Our strategy has advantages for simple fabrication, scalable manufacturing, high-density integration, large strain tolerance and low cost,” he said.

Yu and the rest of the team – co-authors include first author Hae-Jin Kim, Kyoseung Sim and Anish Thukral, all with the UH Cullen College of Engineering – created the electronic skin and used it to demonstrate that a robotic hand could sense the temperature of hot and iced water in a cup. The skin also was able to interpret computer signals sent to the hand and reproduce the signals as .

The robotic skin can translate the gesture to readable letters that a person like me can understand and read,” Yu said.

The work is reported in the journal Science Advances.


How To Draw Electricity from the Bloodstream

Men build dams and huge turbines to turn the energy of waterfalls and tides into electricity. To produce hydropower on a much smaller scale, Chinese scientists have now developed a lightweight power generator based on carbon nanotube fibers suitable to convert even the energy of flowing blood in blood vessels into electricity.

For thousands of years, people have used the energy of flowing or falling water for their purposes, first to power mechanical engines such as watermills, then to generate electricity by exploiting height differences in the landscape or sea tides. Using naturally flowing water as a sustainable power source has the advantage that there are (almost) no dependencies on weather or daylight. Even flexible, minute power generators that make use of the flow of biological fluids are conceivable. How such a system could work is explained by a research team from Fudan University in Shanghai, China. Huisheng Peng and his co-workers have developed a fiber with a thickness of less than a millimeter that generates electrical power when surrounded by flowing saline solution—in a thin tube or even in a blood vessel.

The construction principle of the fiber is quite simple. An ordered array of carbon nanotubes was continuously wrapped around a polymeric core. Carbon nanotubes are well known to be electroactive and mechanically stable; they can be spun and aligned in sheets. In the as-prepared electroactive threads, the carbon nanotube sheets coated the fiber core with a thickness of less than half a micron. For power generation, the thread or “fiber-shaped fluidic nanogenerator” (FFNG), as the authors call it, was connected to electrodes and immersed into flowing water or simply repeatedly dipped into a saline solution. “The electricity was derived from the relative movement between the FFNG and the solution,” the scientists explained. According to the theory, an electrical double layer is created around the fiber, and then the flowing solution distorts the symmetrical charge distribution, generating an electricity gradient along the long axis.

The power output efficiency of this system was high. Compared with other types of miniature energy-harvesting devices, the FFNG was reported to show a superior power conversion efficiency of more than 20%. Other advantages are elasticity, tunability, lightweight, and one-dimensionality, thus offering prospects of exciting technological applications. The FFNG can be made stretchable just by spinning the sheets around an elastic fiber substrate. If woven into fabrics, wearable electronics become thus a very interesting option for FFNG application. Another exciting application is the harvesting of electrical energy from the bloodstream for medical applications. First tests with frog nerves proved to be successful.

The findings are published in  the journal Angewandte Chemie.


Big Data And Skyrmions

Today’s world, rapidly changing because of “big data”, is encapsulated in trillions of tiny magnetic objects magnetic bits – each of which stores one bit of data in magnetic disk drives.   A group of scientists from the Max Planck Institutes in Halle and Dresden have discovered a new kind of magnetic nano-object in a novel material that could serve as a magnetic bit with cloaking properties to make a magnetic disk drive with no moving parts – a Racetrack Memory – a reality in the near future.

Most digital data is stored in the cloud as magnetic bits within massive numbers of magnetic disk drives.  Over the past several decades these magnetic bits have shrunk by many orders of magnitude, reaching limits where the boundaries of these magnetic regions can have special properties.  In some special materials these boundaries – “magnetic domain walls” – can be described as being topological. What this means is that these walls can be thought of as having a special magical cloak – what is referred to by scientists as “topological protection”.   An important consequence is that such magnetic walls are more stable to perturbations than similar magnetic bits without topological protection that are formed in conventional magnetic materials.  Thus, these “topological magnetic objects could be especially useful for storing1”s and “0”s, the basic elements of digital data.   One such object is a “magnetic skyrmion” which is a tiny magnetic region, perhaps tens to hundreds of atoms wide, separated from a surrounding magnetic region by a chiral domain wall.  Until recently only one type of skyrmion has been found in which it is surrounded by a chiral domain wall that takes the same form in all directions.   But there have been predictions of several other types of skyrmions that were not yet observed.

Now in a paper published in Nature, scientists from Prof. Stuart Parkin’s NISE department at the Max Planck Institute for Microstructure Physics in Halle, Germany, have found a second class of skyrmions, what are called “anti-skyrmions”, in materials synthesized in Prof. Claudia Felser.   The scientists from Halle and Dresden have found these tiny magnetic objects in a special class of versatile magnetic compounds called Heusler compounds.   Of these Heusler compounds, a tiny subset have just the right crystal symmetry to allow for the possibility of forming anti-skyrmions but not skyrmions.

The special cloaking properties of skyrmions makes them of great interest for a radically new form of solid-state memorythe Racetrack Memory. In Racetrack Memory digital data is encoded within magnetic domain walls that are packed closely within nanoscopic magnetic wires.  One of the unique features of Racetrack Memory, which is distinct from all other memories, is that the walls are moved around the nanowires themselves using recent discoveries in spin-orbitronics domain walls.  Very short pulses of current move all the backwards and forwards along the nano-wires. The walls – the magnetic bits – can be read and written by devices incorporated directly into the nanowires themselves, thereby eliminating any mechanical parts.


More Durable Fuel Cells For Hydrogen Electric Car

Take a ride on the University of Delaware’s (UDFuel Cell bus, and you see that fuel cells can power vehicles in an eco-friendly way. In just the last two years, Toyota, BMW and Honda have released vehicles that run on fuel cells, and carmakers such as GM, BMW and VW are working on prototypes.  If their power sources lasted longer and cost less, fuel cell vehicles could go mainstream faster. Now, a team of engineers at UD has developed a technology that could make fuel cells cheaper and more durable.

Hydrogen-powered fuel cells are a green alternative to internal combustion engines because they produce power through electrochemical reactions, leaving no pollution behind. Materials called catalysts spur these electrochemical reactions. Platinum is the most common catalyst in the type of fuel cells used in vehicles. However, platinum is expensive — as anyone who’s shopped for jewelry knows. The metal costs around $30,000 per kilogram. Instead, the UD team made a catalyst of tungsten carbide, which goes for around $150 per kilogram. They produced tungsten carbide nanoparticles in a novel way, much smaller and more scalable than previous methods.

The material is typically made at very high temperatures, about 1,500 Celsius, and at these temperatures, it grows big and has little surface area for chemistry to take place on,” explains Vlachos, professor at the Catalysis Center for Energy Innovation (UD). “Our approach is one of the first to make nanoscale material of high surface area that can be commercially relevant for catalysis.”

The researchers made tungsten carbide nanoparticles using a series of steps including hydrothermal treatment, separation, reduction, carburization and more. The results are described in a paper published in Nature Communications.