Tag: graphene

Graphene modulator means 3D film download in seconds

Scientists have found tiny optical devices using wonder material graphene could soon be used to reach download times “up to ten times faster” than currently seen.

Modulators are used in data communications to control the speed at which data packets are transmitted, with faster data pulses meaning greater volumes of information can be sent out.

Now scientists led by UC Berkeley engineering professor Xiang Zhang have devised an optical device based on graphene to switch light on and off as an “incredibly compact modulator”, which the scientists claim is the world’s smallest.

According to the scientists this means it will be possible to “significantly enhance our capabilities in ultrafast optical communication and computing”.

This could mean allowing to stream cutting edge content such as 3D movies onto your phone in a matter of seconds in the near future the scientists.

It is yet another surprising use for the material developed by researchers at the University of Manchester following the discovery of its properties after messing around with some sellotape, perhaps the most ingenious use of sticky-back plastic since Blue Peter showed kids how to create a high-street level Tracy Island from household goods packaging in the mid nineties.

Electric charges were applied to a sheet of graphene on top of a silicon ‘waveguide’, with the voltage running through the graphene changing the materials transparency and therefore abiliity to turn light on and off to function as a modulator.

This very basically works by passing many electrons elctrons through the graphene enabling photons to be absorbed and thus rendering the material opaque, or passing a negative voltage through can cause the drawing out of electrons and therefore leaving the material transparent and turning the light ‘on’.

The researchers were able to achieve a modulation speed of one gigahertz, though they believe that 500 gighertz could possibly be reached on a single modulator. 

In the past attempts to use optics rather than electricity have been hampered due to difficulties in implementing bulky optics onto computer chips, as light waves are “less agile” in tight spaces comparatively and so are mainly used in large scale devices such as fibre optics.

However they are among other things able to carry data packets more quickly, and graphene based devices could get round these problems, shrinking the devices down to 25 microns, much smaller than some commercial modulators which can be as big as a few square millimetres.

In fact the scientists say that the graphite used in one pencil is the equivalent of one billion modulators worth of graphene.

The researchers believe that this means instead of broadband it will be possible to achieve the rather more hyperbolic “extremeband”, and hope to see industrial applications of the new device in the “next few years”.

TSMC eyes seven nanometre process

Taiwan Semiconductor Manufacturing Co (TSMC) has confirmed that pilot production of its 20 nanometre process will begin in the second half of 2012.

The firm’s senior vice president in charge of R&D, S.Y. Chiang announced that its first foray into 450 millimetre wafer production would occur late next year, following on from the 28 nm pilot production in the second quarter of this year.

Chiang also noted that TSMC would begin its volume production phase of the 28nm technology towards the end of 2011, producing more than twice as many chips as the 40 nm process, with IC designs being finalised this year.

All of which fits in with Moore’s Law, stating that the numbers of transistors will roughly double every eighteen months since the 1965 invention of integrated circuits. But semiconductor expert Malcolm Penn said  that TSMC’s announcement about the new process is “like saying Christmas will be happening in December this year”.

With regards to future adherence to Moore’s Law, Chiang estimates that the rule will remain applicable to the semi industry until at least when the  seven nanometre process comes into production.

Chiang also predicted that the room for cooperation between both silicon foundries and chip assemblers will increase as the size of single chips and system chips continues to be scaled down.

Penn agrees that the shrinking of process size will continue up until the seven nanometre threshold, where the way that the physics involved in the circuits begins to change.

“At this point it becomes a different ball game,” Penn said, “with molecular level circuits and talk of single atom transistors as the physics change from here on out.”

This is where new developments in graphene based circuitry, spintronics and other exotic developments which are occurring in labs at early stages of research come into play.

Such technologies are a good while from becoming viable in production on a large level, but Penn believes we have around ten to fifteen years before the 7nm process is reached.

Up until then, though, Penn believes that progression should remain steady, with the step on the horizon being 16 or 14 nm, “depending on what your marketing department decides as they are both pretty much exactly the same.”

IBM's graphene transistors pave way for commercial production

IBM has developed its fastest graphene transistor to date, able to execute 155 billion cycles per second, with expectations that commercially viable processors could be on their way in the not too distant future.

The transistor is around 50 percent faster than previous prototypes developed by the firm’s researchers, with IBM responsible for breakthrough technologies in a variety of fields these days, beating the previous 100GHz record set by a graphene transistor last year.

The development comes after the firm has been setting its sights on graphene eventually overtaking silicon with it unusual properties offering a nubemr of potential benefits.

According to researcher Yu-Ming Lin, the steps made in this research have shown that processors based on wonder material graphene could be produced at low cost, using standard semiconductor processes, meaning that their widespread use could be a reality soon.

With the high strength of the material and fast flow of electrons compared to conventional materials there are many applications such as wireless communications and networking that would use the attributes of graphene in passing information to chips at an increased speed.

While there may be many applications that are currently fit for graphene, Lin notes that implementation in PCs is not one that is likely to be used just yet, with a lack of a natural energy gap in natural graphene meaning that the on-off ratio required for digital switching operations won’t fit the bill.

Processing analogue signals are where graphene’s strength lies for now though according to Lin, where a high on-off ratio is not required.

In terms of size the new transistor is IBM’s smallest to date according to the research team, with the gate length of the radio-frequency graphene transistor reduced from 550 nanometres to 40 according to PC World.

And the fact that it was produced with the same process technology that is used in silicon device fabrication means that the material, brought to notoriety by Russsian scientists Andre Geim and Konstantin Novoselov at the University of Manchester, is increasing viable in terms of commercial production.

A chief tech strategist at In-Stat highlighted that graphene is a material that the industry is only beginning to come to terms with, stating that like any new materials technology it takes billions of investment dollars to develop, a sentiment echoed in the House of Lords recently.

He also said that if existing technologies are to hit a brick wall in development in terms of physics it will be vital to move to another material sch as graphene, adding that to do so will involve the material fitting the three most elements of semi manufacturing; materials, transistor design and lithography.

But if the much vaunted material can be supported through existing and future lithography processes and transistor designs then its use it certainly like to be more widespread in the future.

Graphene chips will self-cool

Following the Nobel prize awarded to two Russian scientists at Manchester University for their work in discovering the properties of graphene, it is widely known that the material exhibits some potentially staggering properties.

For example, the material, can be formed into one atom-thick layers that have properties such as being 100 times stronger than steel and the ability to conduct electricity faster than silicon.

Now scientists have found another surprising benefit of the material that could help bring about revolutionary computer chips, with grapehene being able to cool itself, preventing overheating.

This is of course a major problem for computers which expend a massive amount proportion of their power in just making sure that the ‘resistive heat’, essentially the heat generated as electrons collide within a material, is cooled with fans or flowing water.

In silicon this resistive heating effect outweighs other thermoelectric cooling effects that it displays, meaning that current electronic devices need to incorporate the space for cooling equipment in their designs.

However, researchers at the University of Illinois how shown that graphene shows much stronger cooling effects on its own which could mean that chips in the future will not need to be cooled at all – as the material handily performs that function itself.

Using an atomic force microscope tip as a temperature probe the scientists were for the first time able to reveal more about the thermoelectric properties of graphene, which have so far eluded scientists due to the tiny dimensions involved, according to well-named Professor Eric Pop.

Pop also highlighted the fact that knowledge of graphene is still in its infancy with regards to thermoelectric properties, but insists that “measurements and simulations project that thermoelectric effects will become enhanced as graphene transistor technology and contacts improve”.

Overall the news of the team’s uncovering of new properties in grapehene shows that despite the leap made by the Nobel prize winners, Andre Geim and Kostya Novoselov, there is plenty of exciting work ahead in making graphene into a viable tool for the future of electronics.

Lord demands funding for UK science breakthroughs

A House of Lords representative called for an increase in funding for the science sector in order to continue to attract the expertise that led to the Nobel prize-winning discovery of graphene’s properties.

Lord Rees of Ludley demanded that a four year decline in funding was reversed in order to continue to attract top talent like that of Andre Geim and Kostya Novoselov, the two Russians who came to the UK in 1999 to study at Manchester University, before making their famous discovery.

Now Lord Rees has demanded that more is done to continue to support scientists such as Geim and Novoselov, warning that while the initial experiment resulted in small costs, its subsequent development into a commercially viable material “will not be so cheap and it will be fully as intellectually challenging”.

The Lord went on to question whether the two Russians would now be attracted to a scientific environment in which the total UK funding does not even match that of the bonus pool for London’s bankers.

Indeed as England attempts to break away from dependence on its financial sector, Lord Rees suggested that by leading in scientific developments this would indeed be possible albeit if a welcoming environment is made, rather than a culture of cuts.

“Science and innovation are essential engines if we are to rebalance our economy away from an overdependence on the financial sector,” he said.

“Therefore, most crucial in enhancing value for money for taxpayers is not scraping a few per cent in efficiency savings; it is maximising the chance of big breakthroughs by attracting and supporting top mobile talent and sending positive signals to the young.”

Lord Rees called for a 10 to 15 year road map in which focus and support for innovation is guaranteed in order to “ensure that some of the key ideas of the 21st century are generated and, even more important, exploited here”.

The words of the Lords representative echoed that of IEEE president Moshe Kam, who, speaking to Techeye, highlighted his own concerns in the wider field of engineering and the decline that he perceived in the UK higher education system over the past few years.

Just like Lord Rees Kam highlighted the long term financial benefits of providing a positive environment and support network for engineers and scientists.

Atom-thick materials materialise in Oxford

Scientists have developed a method of splitting materials similar to graphite into atom-thin sheets, leading to applications for new electronic technologies.

The  team led by scientists at Oxford University and Trinity College have found a way to create such nano-sheets in a quick and inexpensive manner, which can be scaled up to work on an industrial level – threatening to steal the thunder from the nation’s favourite two dimensional material, graphene.

The team used mild ultrasonic pulses and common solvents to separate the materials into incredibly thin sheets, in the same way that the graphite has recently made the headlines for being split into layers of ultra-strong graphene.

It is said that a one-millimetre-thick layer of graphite could be broken into three million layers of graphene that measure just one atom in thickness.

According to the researchers there are over 150 layered materials such as Boron Nitride, Molybdenum disulfide, and Tungsten disulfide that can potentially be metallic, semi-metallic or semiconducting depending on their chemical composition and how their atoms are arranged.

“Because of its extraordinary electronic properties graphene has been getting all the attention, including a recent Nobel Prize, as physicists hope that it might, one day, compete with silicon in electronics,” said Dr Valeria Nicolosi of Oxford University’s Department of Materials.

“But in fact there are hundreds of other layered materials that could enable us to create powerful new technologies.”

According to Professor Coleman, of Trinity College Dublin, the nano-materials have chemical and electronic properties which are well suited for applications in new electronic devices, as well as super-strong composite materials and energy generation and storage.

Previous attempts have been made to create nano-sheets from other types of materials, but until now it has proved impractical as the methods were considered too time consuming, and resulted in materials that were too fragile to be realistically be used.

However the scientists believe they have a new method which allows low cost, high yield results, claiming that with only one milligram of material, many billions of atom-thick sheets can be made at the same time from a wide variety of exotic layered materials.

The nanosheets created through this method can then be sprayed onto the surface of other materials like silicon to produce hybrid films which can potentially allow their abilities to be integrated with conventional technologies.

Dr Nicolosi told TechEye that the uses for the new method are manifold, with applications dependent on the specific material that is being used.

“There are a range of possibilities for this, as it means that we are able to produce a wide range of effects in terms of electronic properties,” she said.

“One of the main functions that are possible is in thermoelectronics, where for example the heat waste of a car can be absorbed by the material and converted into electricity.

“Also materials could be used easily for superconducting, with the ability to store massive amounts of energy, as well as being released very efficiently.

“For laptop batteries this could mean that, rather than your battery dying after a year, it could operate like brand new for a much longer time.

“This is because the battery’s material is essentially destroyed while charging, however the new materials are vastly more robust.”

Graphene is a silicon contender

Graphene has the potential to replace silicon in transistors but it’s a long way off.

“It is possible that this could replace silicon, there’s been a lot of hype about Graphene,” a professor researching the applications of Graphene told us.

Nobel Prize winning Graphene has been hotly tipped to be the next major breakthrough for electrics and semiconductors with companies such as  IBM making the claim. It announced a transistor made of an atom-thick layer of carbon atoms, which promised frequencies of 100 billion cycles per second.

IBM said at the time that the frequency performance of the graphene device exceeded the cut off frequency of silicon transistors of the same gate length.

Researchers agree that Graphene could one day trump silicon for certain applications. Dr Karl Coleman, reader in the Department of Chemistry at Durham University, told TechEye: “Graphene has the potential to take over from Silicon, mainly because of the potential speeds that it can switch operate. The transition speeds can switch to hundreds of gigahertz and it potentially has the power to go to terahertz.

“This means it will enable ultrafast switching for devices, the faster you can switch the better.” Coleman said Silicon is flawed in this respect as it can only switch at low gigahertz.

Although this technology is exceeding silicon in terms of fabrication, there is still a long way to go.

“The potential is there and switching is the real benefit. It’s a race at the moment to see how fast this technology can go but it’s important to note this isn’t yet a like for like replacement to silicon,” he added.

Professor Simon Bending, a researcher at the Centre for Graphene Science at Exeter University told us: “It is possible that this could replace silicon. However, there are still a few issues with the technology, notably that it’s a metal so there’s no bandgap, which means it can’t be switched on and off. However we are always using modifications to get around this.”

Graphene is conventionally a one-atom-thick honeycomb crystal lattice material, which has many properties, including the ability to serve as a superconductor, and other properties ideal for transistors.

Moore's Law lives but silicon CMOS is doomed

While Intel is confident Moore’s Law will continue well into the future, an analyst has warned that tough times are ahead for silicon based CMOS devices.

Mike Bryant, CTO of analyst firm Future Horizons, said that there isn’t a reliable silicon transistor based 16 nanometre technology.  

He said leakage and other problems will make silicon based transistors too unreliable as the process continues to shrink. He said the properties of silicon limit the drive current to barely enough to drive the next gate.

While the industry may well solve that problem at a 16 nanometre process, Bryant said that the industry needs an alternative.

At 10 nanometres, said Bryant, Quantum Mechanics will overpower Newtonian physics. Unpredictable and variable “electron clouds” will have to be accounted for, with digital circuits fundamentally fault tolerant.

He quoted Niels Bohr’s (pictured, above left) observation: “Anyone who does not have a headache after first encountering quantum mechanics clearly has not understood a thing.”

But, Bryant observed, there are alternatives to silicon based CMOS. A strontium-germanium interlayer between a hi-k insulator and germanium channel will provide more generations. III-IV materials are less compatible with existing process technology.

He suggested that alternatives to Si CMOS include C60 nanotubes and graphene and diamond transistors.  He said that the carbon based benzene ring is likely to be the smallest switching building block, with a hexagon width of .28 nanometres and transistor size with gold contacts of around one nanometre.

3D transistor layers will rise on a single die, not a stacked die.

Nevertheless, he said the silicon wafer will be the base for multi-trillion element systems until nanobiotechnology replaces them. Whatever the future, quipped Bryant, computers on non silicon CMOS will probably still be running Microsoft Windows.

On 450mm wafers, Bryant said that developing equipment will cost $25 billion or so, a 450mm fab about $8 billion, and transition costs $100 billion. He said the likely date for a 450mm fab to come onstream is 2017, but that would be at the 11 nanometre process level.

There will be difficulties with EUVL lithography, and yields for non memory devices will be reduced at 450mm.

Only Intel, Samsung and TSMC have said they want to move to the larger wafer size – the rest of the industry is reluctant to make a move. The difficulty is the cost of making 450mm fabs can’t be paid for in terms of current profits.

Europe, he said, is concerned with semiconductor processing equipment and there;s rumours that there will be a 450mm pilot plant built in Crolles.  Intel, Samsung, and TSMC aren’t going to fund the cost of the move to the larger wafer size, and so governments may have to, Bryant suggested.

Team takes 'huge step' towards commercial graphene production

It’s great stuff, graphene – sheets of carbon a single atom thick with the potential to create super-efficient transistors that could revolutionise electronics.

But unfortunately, it’s very hard to come by. Current production methods are expensive – indeed, until a couple of years ago, graphene was one of the most expensive substances on earth.  Even now, production is highly inefficient, producing limited amounts of questionable quality.                

But a European team now reckons it has taken a huge step towards viable commercial production.

Victor Aristov of the Leibniz Institute for Solid State and Materials says that it’s a “very simple procedure for making graphene on the cheap.”

His team has grown high-quality graphene on the surface of commercially available silicon carbide wafers to produce material with excellent electronic properties, he says.

It had been thought that the substrate they used, cubic 3C-SiC, or β-SiC, wouldn’t be suitable because of its cubic lattice structure.

“Contrary to common belief, we succeeded in growing high-quality graphene on cubic β-SiC and found that the interaction with the substrate is almost negligible, rendering this system a perfect candidate for future graphene-based electronics,” says the team in its report.

This is a big step forward, as cubic β-SiC is widely grown commercially.

The development “represents a huge step toward technological application of this material, as the synthesis is compatible with industrial mass production,” says Aristov.

The study appears in Nano Letters.