Posts belonging to Category semiconductors

Semiconductors As Thin As An Atom

A two-dimensional material developed by physicist Prof. Dr. Axel Enders (Bayreuth University  in Germany) together with international partners could revolutionize electronicsSemiconductors that are as thin as an atom are no longer the stuff of .  Thanks to its semiconductor properties, this material could be much better suited for high tech applications than graphene, the discovery of which in 2004 was celebrated worldwide as a . This new material contains carbon, boron, and nitrogen, and its chemical name is “Hexagonal Boron-Carbon-Nitrogen (h-BCN)”. The new development was published in the journal ACS Nano.

2D material Bayreuth University

Our findings could be the starting point for a new generation of electronic transistors, circuits, and sensors that are much smaller and more bendable than the electronic elements used to date. They are likely to enable a considerable decrease in power consumption,” Prof. Enders predicts, citing the CMOS technology that currently dominates the electronics industry. This technology has clear limits with regard to further miniaturization. “h-BCN is much better suited than graphene when it comes to pushing these limits,” according to Enders.

Graphene is a two-dimensional lattice made up entirely of carbon atoms. It is thus just as thin as a single atom. Once scientists began investigating these structures more closely, their remarkable properties were greeted with enthusiasm across the world. Graphene is 100 to 300 times stronger than steel and is, at the same time, an excellent conductor of heat and electricity.


Nano Printing Heralds NanoComputers Era

A new technique using liquid metals to create integrated circuits that are just atoms thick could lead to the next big advance for electronics. The process opens the way for the production of large wafers around 1.5 nanometres in depth (a sheet of paper, by comparison, is 100,000nm thick). Other techniques have proven unreliable in terms of quality, difficult to scale up and function only at very high temperatures – 550 degrees or more.

Professor Kourosh Kalantar-zadeh, from RMIT’s School of Engineering in Australia , led the project with  colleagues from RMIT and researchers from CSIRO, Monash University, North Carolina State University and the the University of California, He observed that the electronics industry had “hit a barrier.

nano printing

The fundamental technology of car engines has not progressed since 1920 and now the same is happening to electronics. Mobile phones and computers are no more powerful than five years ago. That is why this new 2D printing technique is so important – creating many layers of incredibly thin electronic chips on the same surface dramatically increases processing power and reduces costsIt will allow for the next revolution in electronics.

Benjamin Carey, a researcher with RMIT and the CSIRO, said creating electronic wafers just atoms thick could overcome the limitations of current chip production. It could also produce materials that were extremely bendable, paving the way for flexible electronics. “However, none of the current technologies are able to create homogenous surfaces of atomically thin semiconductors on large surface areas that are useful for the industrial scale fabrication of chips.  Our solution is to use the metals gallium and indium, which have a low melting point.  These metals produce an atomically thin layer of oxide on their surface that naturally protects them. It is this thin oxide which we use in our fabrication method,”  explains Carey.

By rolling the liquid metal, the oxide layer can be transferred on to an electronic wafer, which is then sulphurised. The surface of the wafer can be pre-treated to form individual transistors.  We have used this novel method to create transistors and photo-detectors of very high gain and very high fabrication reliability in large scale,” he adds.

The paper outlining the new technique has been published in the journal Nature Communications.


Scalable Production of Conductive Graphene Inks

Conductive inks based on graphene and layered materials are key for low-cost manufacturing of flexible electronics, novel energy solutions, composites and coatings. A new method for liquid-phase exfoliation of graphite paves the way for scalable production.

Conductive inks are useful for a range of applications, including printed and flexible electronics such as radio frequency identification (RFID) antennas, transistors or photovoltaic cells. The advent of the internet of things is predicted to lead to new connectivity within everyday objects, including in food packaging. Thus, there is a clear need for cheap and efficient production of electronic devices, using stable, conductive and non-toxic components. These inks can also be used to create novel composites, coatings and energy storage devices.

A new method for producing high quality conductive graphene inks with high concentrations has been developed by researchers working at the Cambridge Graphene Centre at the University of Cambridge, UK. The novel method uses ultrahigh shear forces in a microfluidisation process to exfoliate graphene flakes from graphite. The process converts 100% of the starting graphite material into usable flakes for conductive inks, avoiding the need for centrifugation and reducing the time taken to produce a usable ink. The research, published in ACS Nano, also describes optimisation of the inks for different printing applications, as well as giving detailed insights into the fluid dynamics of graphite exfoliation.

graphene scalable production

“This important conceptual advance will significantly help innovation and industrialization. The fact that the process is already licensed and commercialized indicates how it is feasible to cut the time from lab to market” , said Prof. Andrea Ferrari, Director of the Cambridge Graphene Centre.


Drones Re-Charging Wireless While Airborne

Scientists have demonstrated a highly efficient method for wirelessly transferring power to a drone while it is flying. The breakthrough could in theory allow flying drones to stay airborne indefinitely by simply hovering over a ground support vehicle to recharge opening up new potential industrial applications.

The technology uses inductive coupling, a concept initially demonstrated by inventor Nikola Tesla over 100 years ago. Two copper coils are tuned into one another, using electronics, which enables the wireless exchange of power at a certain frequency. Scientists have been experimenting with this technology for decades, but have not been able to wirelessly power flying technology.


Now, scientists from Imperial College London (ICL) have removed the battery from an off-the-shelf mini-drone and demonstrated that they can wirelessly transfer power to it via inductive coupling. They believe their demonstration is the first to show how this wireless charging method can be efficiently done with a flying object like a drone, potentially paving the way for wider use of the technology.

To demonstrate their approach the researchers bought an off-the-shelf quadcopter drone, around 12 centimetres in diameter, and altered its electronics and removed its battery. They made a copper foil ring, which is a receiving antennae that encircles the drone’s casing. On the ground, a transmitter device made out of a circuit board is connected to electronics and a power source, creating a magnetic field.

The drone’s electronics are tuned or calibrated at the frequency of the magnetic field. When it flies into the magnetic field an alternating current (AC) voltage is induced in the receiving antenna and the drone’s electronics convert it efficiently into a direct current (DC) voltage to power it.


Printable solar cells

A University of Toronto (U of T) Engineering innovation could make building printing cells as easy and inexpensive as printing a newspaper. Dr. Hairen Tan and his team have cleared a critical manufacturing hurdle in the development of a relatively new class of solar devices called perovskite solar cells. This alternative solar technology could lead to low-cost, printable solar panels capable of turning nearly any surface into a power generator.

Printable Perovskite SolarCell

Economies of scale have greatly reduced the cost of silicon manufacturing,” says University Professor Ted Sargent (ECE), an expert in emerging solar technologies and the Canada Research Chair in Nanotechnology and senior author on the paper. “Perovskite solar cells can enable us to use techniques already established in the printing industry to produce solar cells at very low cost. Potentially, perovskites and silicon cells can be married to improve efficiency further, but only with advances in low-temperature processes.”

Today, virtually all commercial solar cells are made from thin slices of crystalline silicon which must be processed to a very high purity. It’s an energy-intensive process, requiring temperatures higher than 1,000 degrees Celsius and large amounts of hazardous solvents.

In contrast, perovskite solar cells depend on a layer of tiny crystals — each about 1,000 times smaller than the width of a human hair — made of low-cost, light-sensitive materials. Because the perovskite raw materials can be mixed into a liquid to form a kind of ‘solar ink’, they could be printed onto glass, plastic or other materials using a simple inkjet process.


How To Turn Sunlight, Heat and Movement Into Electricity — All at Once

Many forms of energy surround you: sunlight, the heat in your room and even your own movements. All that energy — normally wasted — can potentially help power your portable and wearable gadgets, from biometric sensors to smart watches. Now, researchers from the University of Oulu in Finland have found that a mineral with the perovskite crystal structure has the right properties to extract energy from multiple sources at the same time.

perovskite solar panel

Perovskites are a family of minerals, many of which have shown promise for harvesting one or two types of energy at a time — but not simultaneously. One family member may be good for solar cells, with the right properties for efficiently converting solar energy into electricity. Meanwhile, another is adept at harnessing energy from changes in temperature and pressure, which can arise from motion, making them so-called pyroelectric and piezoelectric materials, respectively.

Sometimes, however, just one type of energy isn’t enough. A given form of energy isn’t always available — maybe it’s cloudy or you’re in a meeting and can’t get up to move around. Other researchers have developed devices that can harness multiple forms of energy, but they require multiple materials, adding bulk to what’s supposed to be a small and portable device.

This week in Applied Physics Letters, Yang Bai and his colleagues at the University of Oulu explain their research on a specific type of perovskite called KBNNO, which may be able to harness many forms of energy. Like all perovskites, KBNNO is a ferroelectric material, filled with tiny electric dipoles analogous to tiny compass needles in a magnet. Within the next year, Bai said, he hopes to build a prototype multi-energy-harvesting device. The fabrication process is straightforward, so commercialization could come in just a few years once researchers identify the best material. “This will push the development of the Internet of Things and smart cities, where power-consuming sensors and devices can be energy sustainable,” he said.

This kind of material would likely supplement the batteries on your devices, improving energy efficiency and reducing how often you need to recharge. One day, Bai said, multi-energy harvesting may mean you won’t have to plug in your gadgets anymore. Batteries for small devices may even become obsolete.


A ”NaNose” Device Identifies 17 Types Of Diseases With A Single Sniff

The future of early diagnoses of disease could be this simple, according to a team of researchers in Israel. The ‘NaNose‘ as they call it can differentiate between 17 types of diseases with a single sniff identifying so-called smelly compounds in anything from cancers to Parkinson’s.


Indeed, what we have found in our most recent research in this regard, that 17 types of disease have 13 common compounds that are found in all different types of disease, but the mixture of the compounds and the composition of these compounds changes from one disease to another disease. And this is what is really unique and what really we expect to see and utilize in order to make the diagnosis from exhaled breat,” says Professor Hossam  Haick ftom the Institute of Technology- Technion.

The NaNose uses “artificially intelligent nanoarraysensors to analyze the data obtained from receptors that “smell” the patient’s breath.

So our main idea is to try an imitate what’s going on in nature. So like we can take a canine, a dog and train it to scent the smell of drugs, of explosives or a missing person, we are trying to do it artificially. And we can do that by using these nano-materials and we build these nano material-based sensors. And of course there are many advantages and one of them of course is going all the way from sensors big as this to really small devices like this that have that have on them eight sensors and which can be incorporated to systems like this, or even smaller,” explains Doctor Yoav Broza from Technion .

Several companies are now trying to commercialize the technology – and encourage its use in healthcare systems… or see it incorporated into your smartphone.


SpaceX Hyperloop A Step Closer To Reality

The Hyperloop high-speed transportation system has moved a step closer to reality. Teams competed to design subscale versions of the transport pods that could one day whisk passengers between San Francisco and Los Angeles in under half an hour. The competition was hosted by SpaceX and its founder, Elon Musk. Although Musk is not directly involved in the construction of the Hyperloop, the billionaire entrepreneur originally envisioned the concept, having created an open-source plan that encouraged others to build it. The idea is that passengers would travel through low-pressure steel tubes at up to 800 mph (1,288 kph), propelled by a magnetic accelerator. The fastest pod in the competition reached 58mph (93 kph). That was designed and built by a 35-person team from the Technical University of Munich, Germany.


What made our team stand out is actually a compressor which we bought out of an old aircraft. It’s there to reduce drag and give us some additional speed.” A team from Delft University of Technology in the Netherlands achieved the highest overall score in the competition for their pod with a levitation, stabilization and braking system based on permanent magnets“, said Josef Fleischmann, member of the WARR team from Technical University of Munich.

Hyperloop, the technology is pretty much there already, we just have to implement it. One of the things this competition is for is to show the world that we can do this and convince them that we should build it somewhere and get the ball rolling,” explains Mars Geuze, technical of Delft Hyperloop.
SpaceX has said it will hold a second competition, open to both new and existing student teams, in Summer 2017, this time focused only on maximum speed.


Hand-Held Breath Monitor To Detect Flu

Perena Gouma, a professor in the Materials Science and Engineering Department at The University of Texas at Arlington, has devised a hand-held breath monitor that can detect the flu virus. The single-exhale sensing device is similar to the breathalyzers used by police officers when they suspect a driver of being under the influence of alcohol. A patient simply exhales into the device, which uses semiconductor sensors like those in a household carbon monoxide detector.  The difference is that these sensors are specific to the gas detected, yet still inexpensive, and can isolate biomarkers associated with the flu virus and indicate whether or not the patient has the flu. The device could eventually be available in drugstores so that people can be diagnosed earlier and take advantage of medicine used to treat the flu in its earliest stages. This device may help prevent flu epidemics from spreading, protecting both individuals as well as the public health.

Gouma and her team relied on existing medical literature to determine the quantities of known biomarkers present in a person’s breath when afflicted with a particular disease, then applied that knowledge to find a combination of sensors for those biomarkers that is accurate for detecting the flu. For instance, people who suffer from asthma have increased nitric oxide concentration in their breath, and acetone is a known biomarker for diabetes and metabolic processes. When combined with a nitric oxide and an ammonia sensor, Gouma found that the breath monitor may detect the flu virus, possibly as well as tests done in a doctor’s office. Gouma’s sensors are at the heart of her breath analyzer device.

breath monitor prototype

I think that technology like this is going to revolutionize personalized diagnostics. This will allow people to be proactive and catch illnesses early, and the technology can easily be used to detect other diseases, such as Ebola virus disease, simply by changing the sensors,” said Gouma, who also is the lead scientist in the Institute for Predictive Performance Measurement at the UTA Research Institute.
Before we applied nanotechnology to create this device, the only way to detect biomarkers in a person’s breath was through very expensive, highly-technical equipment in a lab, operated by skilled personnel. Now, this technology could be used by ordinary people to quickly and accurately diagnose illness.”

The findings are described  in the journal Sensors Source.

Reconfigurable Materials

Metamaterialsmaterials whose function is determined by structure, not composition — have been designed to bend light and sound, transform from soft to stiff, and even dampen seismic waves from earthquakes. But each of these functions requires a unique mechanical structure, making these materials great for specific tasks, but difficult to implement broadly. But what if a material could contain within its structure, multiple functions and easily and autonomously switch between them?

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute of Biologically Inspired Engineering at Harvard University have developed a general framework to design reconfigurable metamaterials. The design strategy is scale independent, meaning it can be applied to everything from meter-scale architectures to reconfigurable nano-scale systems such as photonic crystals, waveguides and metamaterials to guide heat.

In terms of reconfigurable metamaterials, the design space is incredibly large and so the challenge is to come up with smart strategies to explore it,” said Katia Bertoldi, John L. Loeb Associate Professor of the Natural Sciences at SEAS and senior author of the paper. “Through a collaboration with designers and mathematicians, we found a way to generalize these rules and quickly generate a lot of interesting designs.”

The research is published in Nature.

Device Doubles The Energy Conversion Of Solar Cells

Scientists from Japan are utilizing nanotechnology advancements to strengthen solar cellsSolar cells convert light into electricity using a bevy of sources, including light from the sun and the burning of natural resources such as oil and natural gas. However, the cells do not convert all light to power equally, which led to scientists attempting to find ways to produce more power. The flame of a gas burner will shift from red to blue as the heat increases because higher temperatures emit light at shorter wavelengths. Higher heat offers more energy, making short wavelengths an important target in the design of solar cells. Kyoto University‘s Takashi Asano, began using optical technologies to improve energy production.

device to double the power of solar cells

Current solar cells are not good at converting visible light to electrical power. The best efficiency is only around 20 percent,” Asano said in a statement. “The problem is that heat dissipates light of all wavelengths, but a solar cell will only work in a narrow range. To solve this, we built a new nano-sized semiconductor that narrows the wavelength bandwidth to concentrate the energy.

The researchers were able to use their nanoscale semiconductor to raise the energy conversion rate to at least 40 percent. Asano and researchers at the Susumu Noda lab had previously attempted to work with higher wavelengths. “Our first device worked at high wavelengths but to narrow output for visible light required a new strategy, which is why we shifted to intrinsic silicon in this current collaboration with Osaka Gas,” Asano said. Visible wavelengths are emitted at 1000 degrees Celsius but conveniently silicon has a melting temperature of over 1,400 degrees Celsius.

This concept was utilized by the scientists, who etched silicon plates to have a large number of identical and equidistantly-spaced rods, the height, radii and spacing of which was optimized for the target bandwidth. Susumu Noda, a professor at Kyoto University, explained the benefits of the advancement: “Our technology has two important benefits. First is energy efficiency: we can convert heat into electricity much more efficiently than before. Secondly is design:  we can now create much smaller and more robust transducers, which will be beneficial in a wide range of applications.”

The study was published in Science Advances.


How To Convert Heat Into Electricity

The same researchers who pioneered the use of a quantum mechanical effect to convert heat into electricity have figured out how to make their technique work in a form more suitable to industry. In Nature Communications, engineers from The Ohio State University (OSU) describe how they used magnetism on a composite of nickel and platinum to amplify the voltage output 10 times or more—not in a thin film, as they had done previously, but in a thicker piece of material that more closely resembles components for future electronic devices.

Many electrical and mechanical devices, such as car engines, produce heat as a byproduct of their normal operation. It’s called “waste heat,” and its existence is required by the fundamental laws of thermodynamics, explained study co-author Stephen Boona.

devices-that-convert-heat-into-electricityOver half of the energy we use is wasted and enters the atmosphere as heat,” said Boona, a postdoctoral researcher at Ohio State. “Solid-state thermoelectrics can help us recover some of that energy. These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also too expensive and not quite efficient enough to warrant widespread use. We’re working to change that.”But a growing area of research called solid-state thermoelectrics aims to capture that waste heat inside specially designed materials to generate power and increase overall energy efficiency.