Tag: graphene

Graphene nanoribbons could extend Moore's Law by 10 years

Researchers are developing a technique with everyone’s favourite wonder material, graphene, that could potentially see Moore’s Law extended by 10 years.

The method involves standing atom thin sheets of graphene on a substrate to make high density walls for use on conventional electronic chips.  The same techniques could even be used for ongoing work into spintronics as an alternative to current chip production.

A paper produced by scientists at Rice University and Hong Kong Polytechnic University shows that certain materials such as diamond or nickel can be used to bind strips of graphene nanoribbon.

With the material used in such small quantities to hold the nanoribbons upright, on an atomic scale it is possible for graphene to still exhibit its Nobel prize-winning qualities.

Working with nanoribbons at this size to create field effect transistor, it should be possible to create massive amounts of transistors on a microchip.

With a few billion able to fit on a chip currently, the team are talking up mind boggling numbers.

According to Rice theoretical physicist Boris Yakobson reckons that it will be possible to pack 100 trillion FETs onto a one centimetre square chip.

This would in effect help keep Moore’s Law going by another decade or so.

Yakobson says that he spoke to Moore himself during the infancy of developments into nanotechnology.  Apparently Moore saw silicon wafers in terms of real estate, and Yakobson will now, to extend the metaphor, use upright architecture to go from “ranch-style houses in Texas to skyscraper condos in Hong Kong”.

According to the research of Yakobson and his team, which is clearly in a very early stage, the naoribbons would be able to stand easily at a 90-degree angle. As this is its preferred state minimal energy would be required.

 The walls could then be grown as a close as 7/10ths of a nanometre, which would mean that graphene properties would remain.  This could all be done on a silicon, silicon oxide or other materials.

Two types of nanribbon can be made, of the zigzag or armchair variety.   Zigzag are magnetic  would be useful as they cause electrons to spin off in opposing directions, an important factor in allowing spin to be measured.

Armchair nanoribbons on the other hand can become semiconductors, and can create a large band gap which is essential for creating transistors.

In both cases, the electronic properties of the walls can be tuned by changing their height.

If all goes to plan with development Yakobson reckons that subnanometre electronics coul be on the cards.

 

 

Graphene won't beat silicon circuits until 2024

A computer engineer believes that graphene will eventually replace silicon in commercial circuits, but not until current production methods reach a dead end.

According to James D. Meindl at the Georgia Institute of Technology, graphene will take centre stage once production processes reach the seven nanometre mark.

It is around this point that it is generally thought that CMOS semiconductor manufacturing hits a brick wall.  According to Moore’s Law this is due to happen around 2024, and it is not until this point that graphene is seen as a viable alternative by Meindl.

Since the discovery of graphene by scotch tape wielding researchers at the Manchester University in 2004, there have been many advances in the use of the material and its revelatory properties.  While there are some more short term uses for graphene it seems that it could still be some time before it takes a place at the heart of a new breed of processors.

According to EETimes graphene switches are one of the most likely uses in circuitry, Meindl believes, and he is currently working on 15 nanometre-wide ribbons which could give silicon a run for its money. Graphene transistors also offer a boost over conventional cooper interconnects, and would be ideal for manufacturing MEMS.

However, there are many hurdles in bringing graphene to mass production, as Meindl notes. 

Although there have been successes in graphene integrated circuits, these have amounted to “less than a handful of transistors so far”.  That is some way off the billions of transistors which are currently crammed onto processors.

There are concerns over the lack of ‘energy gap’ in graphene, with doubts raised about the ability to work in a CPU.

This means that a hybrid of graphene and silicon is more likely in the near future at least, with Samsung combining the two materials in memory designs.

Samsung backs graphene-based flash memory

Researchers and engineers have been looking at many potential applications for wonder material graphene in electronics.

IBM has already been working on graphene-based integrated circuits, while Nokia has been looking towards flexible touchscreens for what is likely to be the first commercial application of the material.

Now a team at the University of California, Los Angeles, believes that graphene could help produce a new generation of flash memory products.

Working with Samsung, the team has been trying to incorporate the Nobel prize winning material into its memory storage devices.  If plans come to fruition it could mean storing significantly more information on flash memory devices.

By replacing silicon, it could help extend the longevity of flash memory technology for much longer.

While graphene would not totally replace silicon in the UCLA team’s work, the researchers would use it as a storage layer.  Moreover, it would be used to extend the capabilities of existing technologies, according to TechnologyReview.

Silicon-based flash memory begins to encounter problems with interference once it gets to around the 22 nanometre mark.  This is because the size of transistor gates needs to be thicker as the process gets smaller in order to hold enough charge.

Graphene has extremely thin gates, so would allow for a lot more miniaturisation. In theory, by using graphene for storage it will make it easier to hit the 10nm mark without encountering any hitches.

Samsung is keen enough to put its name to the project.  The scientists are even talking about trying out the graphene flash on commercial processes.

Graphene flash memory should reach industry standards of 10-year projected data retention, the team showed in an ACS Nano paper.

However, at this point the team can only produce memory cells that are much larger, measuring on the micrometre rather than nanometre scale.

But should they be able to miniaturise the technology then at least graphene is a material that is relatively easy to implement, compared to some others.

The days might not yet be numbered for silicon, but it seems graphene is fast becoming either a viable alternative or a worthy complement. 

Girl Scouts cookies produce $15 billion of graphene

Since its discovery by stickytape-toting Manchester University researchers in 2004, graphene has been heralded as a wonder material.

As well as some staggering properties the material can be easily sourced, or so researchers claim.

Now a team at Rice University has uncovered what might be the most abundant source of the highly sought after material yet – Girl Scout cookies.

In fact, they reckon that just one box of the biscuits could have a street value of $15 billion.

According to a report released by the univeristy, any carbon source can be used to yield the raw materials needed for graphene production.

Having discovered that table sugar could produce graphene, the team at Rice University turned to the Houston Girl Scouts to find one of the richest sources yet.

One box of cookies is able to provide enough sugar to cover three football fields.  So with graphene currently retailing at around $250 for a two inch square piece, the value of the cookies ran into the billions of dollars.

“That’s a lot of cash!” said one of the scout troop members, according to a statement.

Despite the draw of big bucks, it certainly opens up some ethical questions.

In the short term graphene could be a good way for scouts to make some extra pocket money. But a ‘sweatshop’ style situation with Girl Scouts churning out box after box to meet global graphene demand should be avoided at all costs.

Along with child labour concerns, there’s an element of discrimination. TechEye contacted Boy Scout groups in the UK and US to hear from Akela about whether it’s unfair that it’s just the girls cashing in on the graphene gold-rush.  

“We have no plans to undertake the production of Graphene in the UK,” the Scout Association told us.

Graphene's first commercial use will be in flexible touchscreens

With the rapid advances made in that wonder material graphene, what we want to know is when we will see it in widespread commercial use for the first time.

It seems that the front runner for the first wide adoption could be in transparent flexible touchscreens. A team of researchers has made further steps towards this with the development of a hybrid graphene film.

The research team, headed up by James Tour, wants to replace indium tin oxide (ITO) which is used in most flat panel displays, meaning smartphones, tablets, solar cells and more.

Graphene offers advantages over ITO, a brittle material – as anyone who has dropped their cracked their screens can agree.

Graphene is significantly more flexible, and could form the basis for wearable, transparent computers.

In economic terms, indium is increasingly in demand, meaning that the price of the rare material has grown over the years. 

But the team at Rice University has combined a single-layer sheet of graphene with a grid of metal nanowires to create a material that it claims is vastly superior to ITO.

While there is other work into pure graphene, Tour believes that there are problems with transparency and conductivity which are resolved through the use of nano-scale aluminium wires.

The five micron-wide wires, about a tenth the size of a human hair, would have no effect on transparency to the human eye.

The researchers believe that the existing production techniques such – as roll to roll – could be used to produce the technology, leading to claims by paper author Yu Zhu that the material is ready to scale right now.

They’ve found that after a fall in the material’s conductivity, after a small number of uses it begins to stabilise.  On a more long term usage basis the material was found extremely resistant.

This means the material can potentially be bent thousands of times without damage.

So, will this be the first commercial application of Manchester University’s Nobel prize-winning graphene? Tour seems to think so, claiming touchscreens are likely to be the first “killer app” to bring graphene to the masses.

TechEye spoke to Dr Andrea C Ferrari, a nanotechnology expert in Cambridge University’s Engineering department, who shares Tour’s belief.

“I do believe that, as things stand at the moment, touchscreens will be the first use of graphene in commercial terms,” he told us.

“Graphene has many properties that make it perfect for use as a touch screen as it is much more flexible than, say, indium tin oxide. In many ways it is almost a perfect material.

“Firms such as Samsung and Nokia are also well aware of this and there is a lot of research into developing graphene for touchscreens in smartphones at this time.

“Of course developments with graphene are occurring at an incredibly rapid pace, so it is impossible to say what will happen in the future. For example, graphene is also being looked at for use in batteries.  Or there could be a more niche use of graphene that sees commercial release before the touchscreens hit the market.”

Indeed, no one knows what is around the corner – and another super-material could pop-up and blow even graphene away, as Ferrari points out.

However, he warns that before we get too excited we may have to wait a while before we actually get our hands on products ready for the market.

“All the physics is understood,” he says, “it is just bringing it to a commercially ready version that will take some time. In principle we know we can get mass production, but it will require investment to bring the price of everything down.

“So we could expect the touchscreens in two to three years,” Ferrari says, “insofar as they are fully developed and functioning models, more complete than working prototypes that are being built now.”

A change in thinking is what will really propel the use of graphene in commercial products, Ferrari suggests: “It used to be that people wanted computers that were faster, but this has changed. Developments are looking at making computers that are more compatible with us.

“This means that we will be able to produce computers that can easily be folded up and tucked away.  With many smartphones not having big enough screens, you could roll out a larger screen from something in your pocket.

“Or you could have a computer sown into the material of your clothes.

“These are just some of the millions of potential uses of graphene as a touchscreen technology.”

Graphene discovery points to large scale production

Scientists have concocted a recipe for growing graphene that will help ease the transition towards its widespread use in electronics devices.

A team of researchers at the Oak Ridge National Laboratory have found that it’s hydrogen rather than carbon which plays a fundamental part in creating a uniform crystalline form.

Not only does hydrogen initiate growth in the wonder material, it is also vital in creating the perfect hexagonal shapes of a “faultless single crystal structure” say the researchers. This is vital in its application with electronics.

In the past, graphene growth has centred around carbon, though this has produced odd-shaped graphene grains that were less likely to be single grains.

The scientists previously thought that hydrogen played a passive role in the growth of graphene. But they have now discovered the effect it has on both “the activation of absorbed molecules that initiate the growth of graphene” and the “elimination of weak bonds at the grain edges that control the quality of the graphene.”

This has opened doors to a method for reliably synthesising the material on a large scale.

Control of the grain size impacts on the functionality of graphene in transistors, semiconductors and “potentially hundreds of electronics devices.”

According to one of the scientists, the use of hydrogen in graphene growth constitutes a “major breakthrough towards graphene implementation in real-world-devices”.

If it brings the use of graphene a step closer then it certainly is an exciting prospect. There are many potential applications of the Nobel-prize winning wonder material, with IBM developing its potential as a future IC technology.

Better notebook batteries – we sure as heck need them

The news that scientists at Monash University are developing systems that might end in superfast rechargeable batteries will come as a boon to anyone who uses a notebook PC.

Ex-Intel engineer Bob Metcalfe famously said some years ago that what “[Andy] Grove gives, [Bill] Gates takes away.”

Every little bit of software eats up battery life, and the peculiar thing is that there hasn’t been very much improvement in life over the last goodness knows how many years.

Of course, the energy pull on your notebook is also considerably reduced by better functionality, by the type of graphics card you have, and most importantly by the display.  The industry has long realised that this has been a problem but the measures it’s taken and the prospects it’s offered – including small fuel cells – have never really materialised. Sure, you can turn down the brightness to extend the battery life a little bit but then you have to really really peer to see what you’re doing.

I’ve used notebooks now since 1986 – over all of those years I’ve had many models but getting more than a few hours without plugging them in has always been a struggle. What really annoys me is that Windows “metre” that one minute tells you have four hours remaining and the next minute tells you you have 20 minutes.  Windows 7 deciding to update you on closedown gets a little bit frightening if you’re nowhere near a socket.

You could argue that if we weren’t using X86 processors and Microsoft Windows we might be happy with the life we get out of li-ion batteries, but they’re not going to go away any time soon now. Sure, netbooks achieve longer battery life, but that’s at the expense of overall functionality.

The boffins at Monash didn’t indicate when we will actually see graphene like batteries in our machine – there are no doubt many obstacles to commercialising the concept and the University didn’t even attempt to estimate when we get our greedy hands on them.

It will be really great to have a notebook that I don’t have to fret over all the time when I’m out on the road covering the technology business. I wonder if it will happen before I shuffle off my mortal coil?

Graphene gel means high speed, long lasting batteries

Graphene – is there anything it can’t do?

Probably. It’ll never score a top ten hit, but following a discovery by researchers at Monash University, the wonder material has added yet another string to its bow.

The team of scientists has developed a method of using the material to recharge batteries at lightning speed, with the mere addition of a splash of tap water.

According to Dr Dan Li, the lead researcher, the graphene discovery means that with some tweaking it could be possible to charge up an iPhone in seconds, or even less.

This means performing on par with lithium ion batteries, as well as the potential for it to last indefinitely.

Having been discovered by two scientists at the University of Manchester mucking around with sticky tape, the Nobel prize winning material’s astounding properties have already seen it used in some fascinating ways.

For example it could be used to create modulators for ‘extremeband’ internet speeds, or a new generation of supercapacitors, while IBM has already begun to use graphene in computer chip design.

And now the material could be used in energy storage applications thanks to its extremely high surface area and conductivity.

These properties are a result of breaking down cheap and readily available graphite into one atom thick layers.

However, as the researchers were aware, problems arise when the material is restacked.

According to Dr Li, when the material is combined into a macrostructure it loses much of its surface area and ceases to behave like graphene any more.

However, they were able to solve this problem by simply adding water.

By keeping the graphene moist the team was, crucially, able to prevent the sheets from restacking, meaing its original properties remain.

The resulting graphene gel nanomaterial has a range of potential applications in energy storage, holding a large amount of charge and expending it at high speeds.

Dr Li believes that it could be beneficial for more effective delivery of renewable energy sources, and could push large scale adoption of electrical vehicles.

There are also possible uses for the gel in water purification membranes, and biomedical devices and sensors.

IBM builds graphene transistor IC

IBM researchers have built the first integrated circuit (IC) based on a graphene transistor.

Graphene promises faster components to challenge the traditional silicon, but there are hurdles which need jumping. In October last year, scientists told us that Graphene had the potential to replace silicon in transistors as its transition speeds switch to hundreds of gigahertz and could even reach terahertz.

At the time, researchers said a replacement is a long way off.

IBM’s researchers, however, claim that with this breakthrough they are another step closer to fully working with the Nobel-prized material.

The circuits were made using existing manufacturing methods, which means there isn’t a need for a whole new construction process. Down the line, among other uses, graphene chips could enable faster, more power-efficient radio communications circuitry for mobile phones, and other wireless devices.

They made a frequency mixer circuit and married a graphene transistor with two metal devices, called inductors.

According to IBM researcher Yu-Ming Lin, the frequency mixer, currently used in mobiles to convert radio signals used to transmit information into a signal in a frequency the human ear can hear, was the main piece to the puzzle. By mixing the radio signal with a reference signal, the transistor was able to handle frequencies of up to 10 GHz.

It wasn’t plain sailing. IBM admitted that it struggled to integrate the graphene with other components. They said it was a “difficult engineering challenge” which took a year to overcome.

According to the IEEE, one of the problems was that graphene didn’t play very nicely with other metals, including aluminium, gold, and palladium which were used to make the rest of the circuit.

Another problem was that graphene is easily damaged by standard semiconductor etching processes.

However, the scientests were not deterred.

Instead they decided to “grow” the graphene on a silicon-carbide wafer.

To give it that extra strength they coated it with a  polymer known as PMMA and a resist that could withstand the jets of electrons used in electron beam lithography. By doing this they were able to create a shield of strength around the graphene, which also meant it could withstand temperatures of around 127 °C.

As a result, a graphene circuit wouldn’t have to be over-designed to compensate for temperature changes.

They wouldn’t have to spend hours creating a complicated circuit, thus saving time and money.

'Activated graphene' provides supercapacitor energy storage boost

Another day, another fascinating use for super-material graphene.

Scientists at the US Department of Energy’s Brookhaven National Laboratory and University of Texas – Austin have devised a method of using the atom thin carbon sheets that is a massive boost in the search for practical supercapacitor materials.

The new form of carbon can be incorporated into supercapacitor devices that are able to store massive amounts of energy while also being able to release it at a quick rate, as well as offering quick recharge time and 10,000 charge/discharge lifecycle.

Basically this is everything that is desirable in a battery, but which is difficult to do with traditional batteries as they store energy through chemical reactions which take considerably more time to react than supercapacitors which rely on charges stored in the form of ions on the surface of electrodes.

According to one researcher,  such properties make the new form of carbon highly useful for energy requirements where a substantial amount is needed at a quick rate, giving electric cars as an example.

So far applications of supercapacitors have been limited to smaller devices such as mobile electronics, though the new form of carbon apparently means that higher energy storage comparable to a battery is possible while still retaining the attributes of supercapacitors, and essentially offering the best of both storage types.

The discovery was made by the team at the University of Texas which had originally attempted to create a porous form of carbon by restructuring “graphene platelets”  and were able to correctly hypothesise the structure of three dimensional networks of atom-thick walls that are able to make the material act like a sponge in soaking up electrical current much more effectively.

The scientists are now looking at how they can manipulate the material to form into structures for specificed functions such as fuel cells, and though this is certainly at the development stage at the moment the team appear confident that they will be able to upscale to industrial production.