AAKASH 2 FINALLY MADE ITS WAY IN INDIAN MARKET!

Aakash 2 is the latest version of Indian government Initiative aakash project which aims at providing tablet to every child of India. The tablet is named after Aakash which means sky or space in Hindi. The first phase suffers a huge setback of performance but the latest version is improved a lot. There is a detailed review of aakash 2. We had dissected almost every specification of the tablet in a detailed manner.

Hardware and Design of aakash 2 tablet

Aakash 2 tab is available in black color with boxy design. The weight of this tiny priced tablet is 350 grams. Its build solidly to cope with the frequent falls in the monsoon’s in the India. The dimension of Aakash 2 is 7.5 inch (190.5 mm) long 4.67 inch (118.5 mm) wide with a thickness of 0.62 inches (15.7 mm). The low weight and handy dimension of aakash makes it possible to carry in your pocket. Aakash  has 2 USB ports for plug and play connectivity of external devices. You can use any 3G USB data card to connect to Internet or you can use your Pen Drive to transfer data from it. A video co-processor is added for better rendering of graphics on video playback. No SIM card is provided in aakash 2 but its present in its commercial version Ubisalte 7+. 35% of hardware components of tablet will be outsourced from South Korea, 16% from the USA, 16% from India, 25% from China and 8% from other countries.

Performance and Battery life of aakash 2 tablet

Aakash tablet 2 is powered by a solid ARM Cortex A8 700 MHz processor which delivers you about 1500 MHz if we are comparing it with ARM 11 processor which is present in BSNL tablet. Means it’s about 1.5 times faster than BSNL tablet even with lower configurations on paper. In the testing phase IIT Rajasthan released the specification of 1200 MHz processor and 1GB RAM in aakash 2 which was not feasible in this budget. RAM of aakash tablet 2 is 256 MB which lets you to execute most of the aaps function smoothly. The internal Memory of the tablet is 2GB flash storage and with a use of simple memory card (SD) card you can extend it up to 32GB. The battery life is also enhanced than and instead of 2100mAh battery of aakash 1 you will get 3200mAh battery in Aakash 2 tab which can runs for 3-4 hours smoothly without any power supply. Aakash 1 has suffered a problem of low memory and frequent system freeze which are worked upon this newer version and looks better than before.

Display, Sound and camera of Aakash 2 tab

Aakash tab 2 display is much better than the previous version. Unlike the resistive touch screen of previous version this version owns capacitive touch screen of 7” inches (18 cm). The resolution of the screen is 800×600 which are fine for small screen. The 7” inch (18cm) screen size is measured diagonally. The tablet consists of a built in microphone for voice recording and voice chat while using any voice chat android app. A 3.5 mm jack is provided with aakash 2 for the connectivity of external speakers to enjoy the music and you can also use the earphones that comes along with the tablet. A headset control is also present in aakash 2. A front end VGA camera is also present in aakash 2 tab commercial version Ubislate 7+ but not in aakash tab.

Software Specs of akash 2 tab

Aakash tablet 2 runs on the Android 2.3 platform also known as Gingerbread. Aakash tab supports (DOC, DOCX, PPT, PPTX, XLS, XLSX, ODT, ODP,PDF), image (PNG, JPG, BMP and GIF), audio (MP3, AAC, AC3, WAV, WMA) and video (MPEG2, MPEG4, AVI, FLV) file formats and also you can access youtube with aakash 2 via a inbuilt android app. A special browser is made or the tablet by Datawind to send the data in compress form to speed up the data streaming even at lower bandwidth. It is expected that normal data will transfer about 6 times faster in this browser than other browser due to the use of advance data compression technology of Datawind. When this data is combined with server side data compression you can get speed about 30 times faster than normal. The commercial version of aakash 2 (ubislate 7+) can connect to Google Android market place for downloading of aaps but nothing is said about the aakash2 tablet. But it can connect to the upcoming government apps portal to download apps and content which are specially designed for aakash 2.

Network and Connectivity of akash 2

Aakash2 supports Wireless Local Area Network (WLAN or Wi-Fi). No SIM card slot is provided to enable any GPRS or 3G connectivity with aakash tab 2. But you can use any 3G stick or Modem of different companies to connect the device to Internet. A  Wi-Fi port (802.11 a/b/g/n) is provided to connect the tablet to internet using Wi-Fi.

Aakash tablet 1 vs aakash 2

There is much advancement from the aakash 1 in aakash 2:

1)      Processor of the tablet is improved a lot the architecture is improved and also the speed as it  runs faster about 3 times and performs quite well as a very less system freezes are observed.

2)      Battery life is improved to 50% i.e you can use the tablet for 3-4 hours without any problem.

3)      The Operating system is upgraded and it now runs Android 2.3 Gingerbread instead of 2.2 Froyo.

4)      Aakash 2 can be connected to Google Android Market place unlike aakash tab 1 which can download only from Getjar.

5)      Touch Screen in aakash 2 is now capacitive instead of Resistive in aakash tab 1.

6)      A front end camera is also predicted in aakash 2 but not yet confirmed.

Aakash 2 vs Ubislate 7+

Ubislate 7+ is the commercial version of aakash tablet 2. The tablet is manufactured by Datawind for Indian Public. The commercial variant of Aakash two is almost similar in specification except a few additional features. The additional features of Ubislate 7+ are

1)      Ubislate 7+ allows user to call i.e we can use it as a phone to call other phones.

2)      The SIM card slot allows to connect the tablet to internet without any external USB modem or Wi-Fi

3)      A front Camera is provided for video calling in the tablet also you can use this camera to capture photos and video (low quality)

4)      The integration of Skype or other Android Apps can enable you to connect to video conferencing or video chatting.

Aakash tab 2 Specifications :

Processor	700 MHZ
Video Processor	HD video co-processor
Connectivity	Wi-Fi( 802.11 a/b/g/n)
Screen Size	7 inch.
Screen Resolution	800×480
Screen Type	Touch Screen Capacitive
Internal Memory	2 GB
Random Access Memory (RAM)	256 MB
Expandable Memory	Upto 32 Gb with SD card slot
USP support	2 USB 2.0 Ports
Audio support	3.5 mm jack
File extension Supported	DOC,DOCX,ODT,ODP,PDF,TXT,XLSX,SLS,PPT,PPTX
Battery Life	3 hrs 3200mAh li-po battery
Dimensions	190.5 mm (7.50 in) Height 118.5 mm (4.67 in) Width 15.7 mm (0.62 in) Thick
Weight	350 gram (12 oz)
Warranty	1 Year replacement warranty

Scientists Build the First All-Carbon Solar Cell

Stanford University scientists have built the first solar cell made entirely of carbon, a promising alternative to the expensive materials used in photovoltaic devices today.

"Carbon has the potential to deliver high performance at a low cost," said study senior author Zhenan Bao, a professor of chemical engineering at Stanford. "To the best of our knowledge, this is the first demonstration of a working solar cell that has all of the components made of carbon. This study builds on previous work done in our lab."

Unlike rigid silicon solar panels that adorn many rooftops, Stanford's thin film prototype is made of carbon materials that can be coated from solution. "Perhaps in the future we can look at alternative markets where flexible carbon solar cells are coated on the surface of buildings, on windows or on cars to generate electricity," Bao said.

The coating technique also has the potential to reduce manufacturing costs, said Stanford graduate student Michael Vosgueritchian, co-lead author of the study with postdoctoral researcher Marc Ramuz.

"Processing silicon-based solar cells requires a lot of steps," Vosgueritchian explained. "But our entire device can be built using simple coating methods that don't require expensive tools and machines."

Carbon nanomaterials

The Bao group's experimental solar cell consists of a photoactive layer, which absorbs sunlight, sandwiched between two electrodes. In a typical thin film solar cell, the electrodes are made of conductive metals and indium tin oxide (ITO). "Materials like indium are scarce and becoming more expensive as the demand for solar cells, touchscreen panels and other electronic devices grows," Bao said. "Carbon, on the other hand, is low cost and Earth-abundant."

The Bao group's all-carbon solar cell consists of a photoactive layer, which absorbs sunlight, sandwiched between two electrodes.

For the study, Bao and her colleagues replaced the silver and ITO used in conventional electrodes with graphene -- sheets of carbon that are one atom thick -and single-walled carbon nanotubes that are 10,000 times narrower than a human hair. "Carbon nanotubes have extraordinary electrical conductivity and light-absorption properties," Bao said.

For the active layer, the scientists used material made of carbon nanotubes and "buckyballs" -- soccer ball-shaped carbon molecules just one nanometer in diameter. The research team recently filed a patent for the entire device.

"Every component in our solar cell, from top to bottom, is made of carbon materials," Vosgueritchian said. "Other groups have reported making all-carbon solar cells, but they were referring to just the active layer in the middle, not the electrodes."

One drawback of the all-carbon prototype is that it primarily absorbs near-infrared wavelengths of light, contributing to a laboratory efficiency of less than 1 percent -- much lower than commercially available solar cells. "We clearly have a long way to go on efficiency," Bao said. "But with better materials and better processing techniques, we expect that the efficiency will go up quite dramatically."

Improving efficiency

The Stanford team is looking at a variety of ways to improve efficiency. "Roughness can short-circuit the device and make it hard to collect the current," Bao said. "We have to figure out how to make each layer very smooth by stacking the nanomaterials really well."

The researchers are also experimenting with carbon nanomaterials that can absorb more light in a broader range of wavelengths, including the visible spectrum.

"Materials made of carbon are very robust," Bao said. "They remain stable in air temperatures of nearly 1,100 degrees Fahrenheit."

The ability of carbon solar cells to out-perform conventional devices under extreme conditions could overcome the need for greater efficiency, according to Vosgueritchian. "We believe that all-carbon solar cells could be used in extreme environments, such as at high temperatures or at high physical stress," he said. "But obviously we want the highest efficiency possible and are working on ways to improve our device."

"Photovoltaics will definitely be a very important source of power that we will tap into in the future," Bao said. "We have a lot of available sunlight. We've got to figure out some way to use this natural resource that is given to us."

Source-www.sciencedaily.com

QUANTUM COMPUTING--MORE FAST AND MORE RELIABLE!!

Combining physics, mathematics and computer science, quantum computing has developed in the past two decades from a visionary idea to one of the most fascinating areas of quantum mechanics. The recent excitement in this lively and speculative domain of research was triggered by Peter Shor (1994) who showed how a quantum algorithm could exponentially “speed-up” classical computation and factor large numbers into primes much more rapidly (at least in terms of the number of computational steps involved) than any known classical algorithm. Shor's algorithm was soon followed by several other algorithms that aimed to solve combinatorial and algebraic problems, and in the last few years theoretical study of quantum systems serving as computational devices has achieved tremendous progress.

While computers have been around for the majority of the 20th century, quantum computing was first theorized less than 30 years ago, by a physicist at the Argonne National Laboratory. Paul Benioff is credited with first applying quantum theory to computers in 1981. Benioff theorized about creating a quantum Turing machine. Most digital computers are based on the Turing Theory.

Defining the Quantum Computer

The Turing machine, developed by Alan Turing in the 1930s, is a theoretical device that consists of tape of unlimited length that is divided into little squares. Each square can either hold a symbol (1 or 0) or be left blank. A read-write device reads these symbols and blanks, which gives the machine its instructions to perform a certain program. Does this sound familiar? Well, in a quantum Turing machine, the difference is that the tape exists in a quantum state, as does the read-write head. This means that the symbols on the tape can be either 0 or 1 or a superposition of 0 and 1; in other words the symbols are both 0 and 1 (and all points in between) at the same time. While a normal Turing machine can only perform one calculation at a time, a quantum Turing machine can perform many calculations at once.

Today's computers, like a Turing machine, work by manipulating bits that exist in one of two states: a 0 or a 1. Quantum computers aren't limited to two states; they encode information as quantum bits, or qubits, which can exist in superposition. Qubits represent atoms, ions, photons or electrons and their respective control devices that are working together to act as computer memory and a processor. Because a quantum computer can contain these multiple states simultaneously, it has the potential to be millions of times more powerful than today's most powerful supercomputers.

This superposition of qubits is what gives quantum computers their inherent parallelism. According to physicist David Deutsch, this parallelism allows a quantum computer to work on a million computations at once, while your desktop PC works on one. A 30-qubit quantum computer would equal the processing power of a conventional computer that could run at 10 teraflops (trillions of floating-point operations per second). Today's typical desktop computers run at speeds measured in gigaflops (billions of floating-point operations per second).

Quantum computers also utilize another aspect of quantum mechanics known as entanglement. One problem with the idea of quantum computers is that if you try to look at the subatomic particles, you could bump them, and thereby change their value. If you look at a qubit in superposition to determine its value, the qubit will assume the value of either 0 or 1, but not both (effectively turning your spiffy quantum computer into a mundane digital computer). To make a practical quantum computer, scientists have to devise ways of making measurements indirectly to preserve the system's integrity. Entanglement provides a potential answer. In quantum physics, if you apply an outside force to two atoms, it can cause them to become entangled, and the second atom can take on the properties of the first atom. So if left alone, an atom will spin in all directions. The instant it is disturbed it chooses one spin, or one value; and at the same time, the second entangled atom will choose an opposite spin, or value. This allows scientists to know the value of the qubits without actually looking at them.

The Qubit

A bit is the basic unit of computer information. Regardless of its physical realization, a bit is always understood to be either a 0 or a 1. An analogy to this is a light switch— with the off position representing 0 and the on position representing 1.

A qubit has some similarities to a classical bit, but is overall very different. Like a bit, a qubit can have two possible values—normally a 0 or a 1. The difference is that whereas a bit must be either 0 or 1, a qubit can be 0, 1, or a superposition of both.

Theoretically, a single qubit can store an infinite amount of information, yet when measured it yields only the classical result (0 or 1) with certain probabilities that are specified by the quantum state. In other words, the measurement changes the state of the qubit, “collapsing” it from the superposition to one of its terms. The crucial point is that unless the qubit is measured, the amount of “hidden” information it stores is conserved under the dynamic evolution (namely, Schrödinger's equation). This feature of quantum mechanics allows one to manipulate the information stored in unmeasured qubits with quantum gates, and is one of the sources for the putative power of quantum computers.

Quantum Gates

Classical computational gates are Boolean logic gates that perform manipulations of the information stored in the bits. In quantum computing these gates are represented by matrices, and can be visualized as rotations of the quantum state on the Bloch sphere. This visualization represents the fact that quantum gates are unitary operators, i.e., they preserve the norm of the quantum state (if U is a matrix describing a single qubit gate, then U^†U=I, where U^† is the adjoint of U, obtained by transposing and then complex-conjugating U). As in the case of classical computing, where there exists a universal gate (the combinations of which can be used to compute any computable function), namely, the NAND gate which results from performing an AND gate and then a NOT gate, in quantum computing it was shown (Barenco et al., 1995) that any multiple qubit logic gate may be composed from a quantum CNOT gate (which operates on a multiple qubit by flipping or preserving the target bit given the state of the control bit, an operation analogous to the classical XOR, i.e., the exclusive OR gate) and single qubit gates. One feature of quantum gates that distinguishes them from classical gates is that they are reversible: the inverse of a unitary matrix is also a unitary matrix, and thus a quantum gate can always be inverted by another quantum gate.

Quantum Circuits

Quantum circuits are similar to classical computer circuits in that they consist of wires and logical gates. The wires are used to carry the information, while the gates manipulate it (note that the wires do not correspond to physical wires; they may correspond to a physical particle, a photon, moving from one location to another in space, or even to time-evolution). Conventionally, the input of the quantum circuit is assumed to be a computational basis state, usually the state consisting of all 0. The output state of the circuit is then measured in the computational basis, or in any other arbitrary orthonormal basis. The first quantum algorithms (i.e. Deutsch-Jozsa, Simon, Shor and Grover) were constructed in this paradigm. Additional paradigms for quantum computing exist today that differ from the quantum circuit model in many interesting ways. So far, however, they all have been demonstrated to be computationally equivalent to the circuit model (see below), in the sense that any computational problem that can be solved by the circuit model can be solved by these new models with only a polynomial overhead in computational resources.

Today's Quantum Computers

Quantum computers could one day replace silicon chips, just like the transistor once replaced the vacuum tube. But for now, the technology required to develop such a quantum computer is beyond our reach. Most research in quantum computing is still very theoretical.

The most advanced quantum computers have not gone beyond manipulating more than 16 qubits, meaning that they are a far cry from practical application. However, the potential remains that quantum computers one day could perform, quickly and easily, calculations that are incredibly time-consuming on conventional computers. Several key advancements have been made in quantum computing in the last few years. Let's look at a few of the quantum computers that have been developed.

1998

Los Alamos and MIT researchers managed to spread a single qubit across three nuclear spins in each molecule of a liquid solution of alanine (an amino acid used to analyze quantum state decay) or trichloroethylene (a chlorinated hydrocarbon used for quantum error correction) molecules. Spreading out the qubit made it harder to corrupt, allowing researchers to use entanglement to study interactions between states as an indirect method for analyzing the quantum information.

2000

In March, scientists at Los Alamos National Laboratory announced the development of a 7-qubit quantum computer within a single drop of liquid. The quantum computer uses nuclear magnetic resonance (NMR) to manipulate particles in the atomic nuclei of molecules of trans-crotonic acid, a simple fluid consisting of molecules made up of six hydrogen and four carbon atoms. The NMR is used to apply electromagnetic pulses, which force the particles to line up. These particles in positions parallel or counter to the magnetic field allow the quantum computer to mimic the information-encoding of bits in digital computers.

Researchers at IBM-Almaden Research Center developed what they claimed was the most advanced quantum computer to date in August. The 5-qubit quantum computer was designed to allow the nuclei of five fluorine atoms to interact with each other as qubits, be programmed by radio frequency pulses and be detected by NMR instruments similar to those used in hospitals (see How Magnetic Resonance Imaging Works for details). Led by Dr. Isaac Chuang, the IBM team was able to solve in one step a mathematical problem that would take conventional computers repeated cycles. The problem, called order-finding, involves finding the period of a particular function, a typical aspect of many mathematical problems involved in cryptography.

2001

Scientists from IBM and Stanford University successfully demonstrated Shor's Algorithm on a quantum computer. Shor's Algorithm is a method for finding the prime factors of numbers (which plays an intrinsic role in cryptography). They used a 7-qubit computer to find the factors of 15. The computer correctly deduced that the prime factors were 3 and 5.

2005

The Institute of Quantum Optics and Quantum Information at the University of Innsbruck announced that scientists had created the first qubyte, or series of 8 qubits, using ion traps.

2006

Scientists in Waterloo and Massachusetts devised methods for quantum control on a 12-qubit system. Quantum control becomes more complex as systems employ more qubits.

2007

Canadian startup company D-Wave demonstrated a 16-qubit quantum computer. The computer solved a sudoku puzzle and other pattern matching problems. The company claims it will produce practical systems by 2008. Skeptics believe practical quantum computers are still decades away, that the system D-Wave has created isn't scaleable, and that many of the claims on D-Wave's Web site are simply impossible (or at least impossible to know for certain given our understanding of quantum mechanics).

If functional quantum computers can be built, they will be valuable in factoring large numbers, and therefore extremely useful for decoding and encoding secret information. If one were to be built today, no information on the Internet would be safe. Our current methods of encryption are simple compared to the complicated methods possible in quantum computers. Quantum computers could also be used to search large databases in a fraction of the time that it would take a conventional computer. Other applications could include using quantum computers to study quantum mechanics, or even to design other quantum computers.

But quantum computing is still in its early stages of development, and many computer scientists believe the technology needed to create a practical quantum computer is years away. Quantum computers must have at least several dozen qubits to be able to solve real-world problems, and thus serve as a viable computing method.

Source-- www.howstuffworks.com

Physicists at The University of Texas at Austin, in collaboration with colleagues in Taiwan and China, have developed the world's smallest semiconductor laser, a breakthrough for emerging photonic technology with applications from computing to medicine.

Miniaturization of semiconductor lasers is key for the development of faster, smaller and lower energy photon-based technologies, such as ultrafast computer chips; highly sensitive biosensors for detecting, treating and studying disease; and next-generation communication technologies.

Such photonic devices could use nanolasers to generate optical signals and transmit information, and have the potential to replace electronic circuits. But the size and performance of photonic devices have been restricted by what's known as the three-dimensional optical diffraction limit.

"We have developed a nanolaser device that operates well below the 3-D diffraction limit," said Chih-Kang "Ken" Shih, professor of physics at The University of Texas at Austin. "We believe our research could have a large impact on nanoscale technologies."

In the current paper, Shih and his colleagues report the first operation of a continuous-wave, low-threshold laser below the 3-D diffraction limit. When fired, the nanolaser emits a green light. The laser is too small to be visible to the naked eye.

The device is constructed of a gallium nitride nanorod that is partially filled with indium gallium nitride. Both alloys are semiconductors used commonly in LEDs. The nanorod is placed on top of a thin insulating layer of silicon that in turn covers a layer of silver film that is smooth at the atomic level.

It's a material that the Shih lab has been perfecting for more than 15 years. That "atomic smoothness" is key to building photonic devices that don't scatter and lose plasmons, which are waves of electrons that can be used to move large amounts of data.

"Atomically smooth plasmonic structures are highly desirable building blocks for applications with low loss of data," said Shih.

Nanolasers such as this could provide for the development of chips where all processes are contained on the chip, so-called "on-chip" communication systems. This would prevent heat gains and information loss typically associated with electronic devices that pass data between multiple chips.

"Size mismatches between electronics and photonics have been a huge barrier to realize on-chip optical communications and computing systems," said Shangjr Gwo, professor at National Tsing Hua University in Taiwain and a former doctoral student of Shih's.

Physicists Explore Properties of Electrons in Revolutionary Material

Scientists from Georgia State University and the Georgia Institute of Technology have found a new way to examine certain properties of electrons in graphene -- a very thin material that may hold the key to new technologies in computing and other fields.

Ramesh Mani, associate professor of physics at GSU, working in collaboration with Walter de Heer, Regents' Professor of physics at Georgia Tech, measured the spin properties of the electrons in graphene, a material made of carbon atoms that is only one atom thick.

The research was published this week in the online-only journal Nature Communications.

Electrons, which follow orbits around the nucleus in atoms, have two important characteristics -- charge and spin.

The electric charge is the basis of most electronic devices, but spin -- which Mani and co-workers examined using a new technique -- forms the basis of new "spintronic" devices, and can serve as a building block for new computers in a field called quantum computing, as well as other technologies.

Graphene is thought to be a key material for spintronic devices, but it is so new that scientists must perform a lot of research on it to understand its capability. The GSU and Georgia Tech study propels this research forward.

"We tried to use the electrical resistance to detect spin resonance. When you shine microwaves on the device, and the microwave energy equals the spin-splitting energy," Mani explained.

"The device absorbs the microwave energy, and that changes the resistance of the device. But this is usually such a small effect that one hardly expects to see it. Fortunately, this material allowed us to see the effect. Measuring spin resonance electrically is especially useful for nanoscale devices."

"By doing such a measurement, we can measure properties like the spin splitting energy, and the spin relaxation time directly," he continued. "There have been other measurements, but those have been a little more indirect."

With the advance in measuring the properties of an electron's spin in graphene, it will allow scientists to carry out further studies of this novel material -- giving researchers ways to optimize graphene for spintronic applications.

Mani noted that that the experiments which were conducted at GSU, were very labor intensive. Simply creating graphene -- which de Heer's laboratory accomplished -- is very time consuming and requires enormous experience.

Measurements use very sophisticated equipment, requiring the researchers to immerse samples in liquid Helium at temperatures close to absolute zero -- about 460 degrees Fahrenheit below zero.

Atlanta has become a center for graphene research, Mani said.

"The confluence of available experimental capability in Atlanta, a hotbed for graphene science and technology, made possible this important advance in the world of spintronics physics," he explained.

The team included Mani of GSU, de Heer, John Hankinson and Claire Berger of Georgia Tech.

Source:- http://www.sciencedaily.com

Original Journal:-Ramesh G Mani, John Hankinson, Claire Berger, Walter A de Heer. Observation of resistively detected hole spin resonance and zero-field pseudo-spin splitting in epitaxial graphene. Nature Communications, 2012; 3: 996 DOI:

New Silicon Memory Chip May Offer Super-Fast Memory

The first purely silicon oxide-based 'Resistive RAM' memory chip that can operate in ambient conditions -- opening up the possibility of new super-fast memory -- has been developed by researchers at UCL.

Resistive RAM (or 'ReRAM') memory chips are based on materials, most often oxides of metals, whose electrical resistance changes when a voltage is applied -- and they "remember" this change even when the power is turned off.

ReRAM chips promise significantly greater memory storage than current technology, such as the Flash memory used on USB sticks, and require much less energy and space.

The UCL team have developed a novel structure composed of silicon oxide, described in a recent paper in the Journal of Applied Physics, which performs the switch in resistance much more efficiently than has been previously achieved. In their material, the arrangement of the silicon atoms changes to form filaments of silicon within the solid silicon oxide, which are less resistive. The presence or absence of these filaments represents a 'switch' from one state to another.

Unlike other silicon oxide chips currently in development, the UCL chip does not require a vacuum to work, and is therefore potentially cheaper and more durable. The design also raises the possibility of transparent memory chips for use in touch screens and mobile devices.

The team have been backed by UCLB, UCL's technology transfer company, and have recently filed a patent on their device. Discussions are ongoing with a number of leading semiconductor companies.

Dr Tony Kenyon, UCL Electronic and Electrical Engineering, said: "Our ReRAM memory chips need just a thousandth of the energy and are around a hundred times faster than standard Flash memory chips. The fact that the device can operate in ambient conditions and has a continuously variable resistance opens up a huge range of potential applications.

"We are also working on making a quartz device with a view to developing transparent electronics."

For added flexibility, the UCL devices can also be designed to have a continuously variable resistance that depends on the last voltage that was applied. This is an important property that allows the device to mimic how neurons in the brain function. Devices that operate in this way are sometimes known as 'memristors'.

This technology is currently of enormous interest, with the first practical memristor, based on titanium dioxide, demonstrated in just 2008. The development of a silicon oxide memristor is a huge step forward because of the potential for its incorporation into silicon chips.

The team's new ReRAM technology was discovered by accident whilst engineers at UCL were working on using the silicon oxide material to produce silicon-based LEDs. During the course of the project, researchers noticed that their devices appeared to be unstable.

UCL PhD student, Adnan Mehonic, was asked to look specifically at the material's electrical properties. He discovered that the material wasn't unstable at all, but flipped between various conducting and non-conducting states very predictably.

Adnan Mehonic, also from the UCL Department of Electronic and Electrical Engineering, said: "My work revealed that a material we had been looking at for some time could in fact be made into a memristor.

"The potential for this material is huge. During proof of concept development we have shown we can programme the chips using the cycle between two or more states of conductivity. We're very excited that our devices may be an important step towards new silicon memory chips."

The technology has promising applications beyond memory storage. The team are also exploring using the resistance properties of their material not just for use in memory but also as a computer processor.

The work was funded by the Engineering and Physical Sciences Research Council.

Source- http://www.sciencedaily.com