7 Posts authored by: ZeroSizeObject


Graphene molecular model image.

A new transistor made from graphene, the world's thinnest material, has been developed by a research team at the University of Southampton. The new transistor achieves a record high-switching performance which will make our future electronic devices, such as PDAs and computers, even more functional and high-performance. “Silicon CMOS downscaling is reaching its limits and we need to find a suitable alternative. Other researchers had looked at graphene as a possibility, but found that one of the drawbacks was that graphene's intrinsic physical properties make it difficult to turn off the current flow,” said Dr. Zakaria Moktadir of the Nano research group at the University. Dr. Moktadir discovered that by introducing geometrical singularities (such as sharp bends and corners) in bilayer graphene nanowires, the current could be turned off efficiently. According to Professor Hiroshi Mizuta, Head of the Nano group, this engineering approach has achieved an on/off switching ratio 1,000 times higher than previous attempts. “Enormous effort has been made across the world to pinch off the channel of GFETs electrostatically, but the existing approaches require either the channel width to be much narrower than 10 nanometres or a very high voltage to be applied vertically across bilayer graphene layers. This hasn't achieved an on/off ratio which is high enough, and is not viable for practical use,” he said. Dr Moktadir developed this transistor using the new helium ion beam microscope and a focused gallium ion beam system in the Southampton Nanofabrication Centre, which has some of the best nanofabrication facilities in the world.



Gallium nitride material holds promise for emerging high-power devices that are more energy efficient than existing technologies, but these GaN devices traditionally break down when exposed to high voltages. Now researchers at North Carolina State University have solved the problem, introducing a buffer that allows the GaN devices to handle 10 times greater power. Previous research into developing high power GaN devices ran into obstacles, because large electric fields were created at specific points on the devices’ edge when high voltages were applied, effectively destroying the devices. NC State researchers have addressed the problem by implanting a buffer made of the element argon at the edges of GaN devices. The buffer spreads out the electric field, allowing the device to handle much higher voltages. The researchers tested the new technique on Schottky diodes and found that the argon implant allowed the GaN diodes to handle almost seven times higher voltages. The diodes that did not have the argon implant broke down when exposed to approximately 250 volts. The diodes with the argon implant could handle up to 1,650 volts before breaking down. “By improving the breakdown voltage from 250 volts to 1,650 volts, we can reduce the electrical resistance of these devices a hundredfold. That reduction in resistance means that these devices can handle ten times as much power,” said Dr. Jay Baliga, Distinguished University Professor of Electrical and Computer Engineering at NC State.




Smaller and more energy-efficient electronic chips could be made using molybdenite. EPFL's Laboratory of Nanoscale Electronics and Structures (LANES) published a study showing that this material has distinct advantages over traditional silicon or graphene for use in electronics applications. This mineral, which is abundant in nature, is often used as an element in steel alloys or as an additive in lubricants. But it had not yet been extensively studied for use in electronics. One of molybdenite's advantages is that it is less voluminous than silicon, which is a three-dimensional material. Another advantage of molybdenite is that it can be used to make transistors that consume 100,000 times less energy in standby state than traditional silicon transistors. A semi-conductor with a ‘gap’ must be used to turn a transistor on and off, and molybdenite's 1.8 electron-volt gap is ideal for this purpose. In solid-state physics, band theory is a way of representing the energy of electrons in a given material. In semi-conductors, electron-free spaces exist between these bands, the so-called ‘band gaps’. If the gap is not too small or too large, certain electrons can hop across the gap. It thus offers a greater level of control over the electrical behavior of the material, which can be turned on and off easily. The existence of this gap in molybdenite also gives it an advantage over graphene. Considered today by many scientists as the electronics material of the future, the ‘semi-metal’ graphene doesn't have a gap, and it is very difficult to artificially reproduce one in the material.



Taiwan-based handset ODM Compal Communications recently unveiled Robii, its first smart robot designed to accompany children aged 5-10, for sale under its own brand UrRobot, according to the company. Robii integrates image/voice recognition, sensors and projection technologies and features interactive learning and gamest based on multi-touch controls. Robii looks like a small monkey and can make more than 100 facial expressions using 170 LED chips and talks, and can track moving objects using built-in cameras and ambient sensors. Through finger-touch controls, Robii can project interactive games and learning content from its screen. Additional content is available online for download, Compal Communications indicated. “This industry-leading robot uses Himax's proprietary Color Filter microdisplay which we feel is a perfect fit for the toy market. We are very excited by the application of our pico-projector technology into the Robii. Up until now the educational toys with interactive features have largely required either a separate television/monitor display or featured small screens on a hand held device. The Robii incorporates projection to eliminate these obstacles and allows for a fun, dynamic and interactive experience right out of the box,” said HC Tsai, Vice President of Himax Display. The monkey robot Robii will sell for about $582, but there is no word as of yet when it will be available.




Quantum applications, from cryptography to computation, all benefit from the use of entangled particles, (photons.) Creating and manipulating these photons is generally pretty straightforward, but storing them is not, which makes the issue of providing memory for a quantum computer a significant hurdle. It has been possible to successfully store some photons, but the media involved—single atoms or cold atomic gasses—aren't necessarily the most practical things to work with. In today's issue of Nature, researchers demonstrate that it's possible to keep two photons entangled even as one of them is held in a crystal. With the crystal properly prepared, it's all just a matter of preparation. By matching the photon and crystal, it's possible to arrange things so that the photon can only be absorbed when the crystal is in its fast transition state. Once it's absorbed, however, the crystal can be shifted to its slow transition state. Once that shift occurs, the photon is trapped. It'll either be released at the slow rate (which takes seconds), or will stick around until the next time the crystal is switched to the fast state. In the intervening time, the photon remains in the crystal in the form of an excited state that is diffused throughout all the doped atoms present. In essence, it occupies the entire crystal, which can be up to a centimeter long. That said, these things still aren't exactly practical. As noted above, the crystals need to sit within a few Kelvin of absolute zero, so they're not quite ready for deployment in a typical computing environment. Although the entanglement could be demonstrated at several standard deviations, the efficiency of putting the photon into the actual crystal wasn't all that great; 21 percent in one case, a fraction of a percent in the other. Still it’s a good step towards bringing quantum memory into reality.




British defense tech firm BAE Systems is developing an active ‘e-camouflage’ system that will employ a form of electronic ink to project imagery of a vehicles surrounding terrain, rendering the vehicle somewhat invisible to potential attackers. Unlike conventional forms of camouflage, the images on the hull would change in concert with the changing environment always insuring that the vehicle remains disguised. The concept was developed as part of the Future Protected Vehicle program, which scientists believe, will transform the way in which future conflicts will be fought. The system exists only on paper currently, but BAE scientists are confident they can make the technology work, with hopes of getting it to British troops serving in Afghanistan in coming years. In fact, the idea was born partially of a problem the troops in Helmand province are having disguising their hardware. All armored units there are painted for desert environs, making them unmistakable even at a distance when they roll into cultivated, green parts of the region. I would say that e-camouflage would have come into existence sooner if we had captured a ‘Predator’ rather than terminate them.




A few unassuming drops of liquid locked in a very precise game of “follow the leader” could one day be found in mobile phone cameras, medical imaging equipment, implantable drug delivery devices, and even implantable eye lenses. Researchers at Rensselaer Polytechnic Institute embedded drops of ferrofluid, a liquid infused with magnetic nanoparticles, into a thin substrate that was submerged in water. Then they exposed the device to a magnetic field to make one of the droplets vibrate back and forth (up or down in the image above), which caused its partner to oscillate in a mirror pattern. This ballet displaces teeny amounts of liquid, moving it from one chamber to another, according to Amir H. Hirsa, a mechanical engineering professor at Rensselaer. The piston is superfast, allowing micro-scale devices with cycling speeds in the kilohertz range. These liquid pistons are highly tunable, scalable, and — because they lack any solid moving parts — suffer no wear and tear. The research team, led by Rensselaer Professor Amir H. Hirsa, is confident this new discovery can be exploited to create a host of new devices ranging from micro displacement pumps and liquid switches, to adaptive lenses and advanced drug delivery systems. For more information please visit: http://news.rpi.edu/update.do


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