For centuries, carbon existed only in two forms: diamond and graphite.
However in the mid-eighties, this changed. An inventor and futurist by the name of Buckminster Fuller observed what later became known as Fullerenes. These are a family of molecules which are made entirely of carbon. They have a hollow shaped tube or spheres.
Yet, until the publication of Japanese scientist Sumio Iijima’s research on carbon nanotubes (CNTs) in 1991, few paid attention to the real world applications of CNTs.
Many wrongly credit Iijima with ‘inventing’ carbon nanotubes. It was in fact Soviet era Russian scientists who first observed CNTs 40 years earlier. But the Soviet government restricted international access to Russian scientific journals.
So it was Iijima’s research that drove the investigation into the potential of carbon nanotubes. His findings got the science boffins buzzing about nanotechnology’s future.
Simply put, CNTs are tubes of carbon, normally only a few nanometres (nm) wide. To put that in context, one millimetre is equal to 10,000,000 nanometres.
But don’t let the small size of CNTs fool you. According to a fabric review website, a carbon nanotube looks ‘like cotton thread, conducts electricity and heat like a metal wire and is as strong as carbon fibres.‘
It’s a big statement, but scientists are only just beginning to test the theoretical possibilities.
Upon discovery, scientists always understood CNTs were the strongest fibre available. They’re extremely lightweight, with a strength to weight ratio 117 times that of steel. They’re one atom thick with high electrical conductivity and thermal properties. Meaning electrons and heat move through them easily.
Because of their tensile strength – the amount of force needed to pull something before it breaks – you’ll find CNTs in niche products. Skis, golf clubs, ultra-light weight bicycles, Kevlar vests and even wind turbines.
The problem is, while scientists were aware of CNT’s possibilities, they haven’t been able to explore the full potential. Mostly this is because carbon atoms are difficult to work with.
And the key to unlocking their potential is controlling the chirality, or it’s ‘twist’. This determines the optical and electronic properties of carbon nanotubes.
Now several universities around the world have developed methods to control this chirality.
This is why the hype around CNTs is back. The new ways discovered allow more control over the carbon, and will ensure it dominates the science journals for next year. You’ll see more and more information on what CNTs could do, can do… and eventually will do.
The opportunities this technology presents are truly mind blowing.
I’ll cover the most exciting research over the next few weeks.
Look, don’t get me wrong. Some big name companies have abandoned their nanotube research for now. Bayer Material Science is one of those. In a statement this year the company said ‘…that the technical potential areas of application that once seemed promising from a technical standpoint are currently either very fragmented or have few overlaps with the company’s core products and their application spectrum.‘
But don’t let a statement like that dismiss the concept.
Just because it doesn’t fit one company’s business model, somewhere in the world, there are many other firms and scientists looking for ways to push the boundaries of what we know.
This may be a bold claim, but within a decade, there’s a chance that silicon computer chips will be a thing of the past. Let me explain…
For the past 20 years, silicon microchips have enabled computers to get smaller and process information quicker than many thought possible.
However, early on in the process of making things smaller, two major problems have been present. The first, is the smaller things got, the smaller the copper wire has to be. But as copper wiring shrinks, so does its conductivity.
The second issue is heat. Silicon chips may have gotten smaller, but the heat they generate has increased. More simply, our electronic devices are hotter. And it’s all because of the silicon transistors. Transistors are semiconductors that provide electronic signals and power, and are a key component of all modern electronics.
Have you ever felt the heat from a laptop, tablet, PC or mobile phone and thought ‘wow, that’s hot’? Well, that’s the silicon transistors working to produce all the power.
In fact silicon chips will soon reach their limits because of these two factors.
You see, for years progress in electronics meant shrinking each transistor.
The smaller a transistor, the more you could put in a device. And the more you could include, the more computer processing power. Simply put, the higher the number of the transistors, the quicker information could move from one component to the other.
But the problem is, silicon transistors generate an immense amount of heat. The more that make up an electrical gadget, the more heat it creates. Not only that, but all the extra heat wastes power. The name for this is ‘energy dissipation’.
And now, shrinking conductivity and energy dissipation are bringing an end to the era of the silicon chip.
Because we’re reaching the upper limits of processing abilities in computers, researchers are working double time to find the next step.
And some engineers at Stanford University in America have done just that.
Many other scientists before the Stanford team tinkered with carbon nanotube transistors. Yet no one had found a way to make a complex circuit, something which could provide a real alternative to integrated circuits, or as we know them, the silicon chips used in modern computing.
The Stanford team were able to use previous research and build on it. Not only did they enhance the fabrication process for CNT based circuits, they went on to develop a ‘wafer thin’ CNT circuit capable of computation.
Stanford professor Subhasish Mitra, an electrical engineer and computer scientist who lead the team, said,’People have been talking about a new era of carbon nanotube electronics moving beyond silicon. But there have been few demonstrations of complete digital systems using this exiting technology.‘
Believe it or not, the picture above is the entire computer. It doesn’t look like much, but it’s a considerable leap for science.
This processor can perform basic counting and number sorting functions. It can even multitask and swap between operating systems.
That’s impressive, given that it only has a total of 178 transistors. That’s nothing when you consider an iPad 4′s microchip has around 200 million transistors.
Also, this wafer thin computer has an operating speed of 1 kilohertz (KHz). Again, the iPad 4 runs at 1,400 megahertz (MHz).
(Now if you don’t ‘speak computer’, kilohertz and megahertz describes the core clock speed of a computer processor. So one KHz represents one thousand cycles per second. One MHz is one million cycles per second.)
By today’s measures, it’s might seem hard to get excited about a computer processor that runs significantly less efficiently than today’s standard. Especially one that can only count and sort numbers.
However, like Stanford Professor Mitra said, it’s an important step in the potential for CNTs to replace silicon in transistors.
This achievement has finally proven there is an alternative to silicon transistors. This breakthrough is proof that CNT computers are doable.
Considering scientists have known for some time the limitations of silicon chips, what took the CNTs researchers so long to finally develop this product?
It mostly came down to technique.
Carbon nanotubes are difficult to work with. The key factor behind the CNT transistors was learning the right technique to ‘grow’ the carbon nanotubes. You see, they don’t grow in straight lines. Only 99.5% of the CNTs form the lines required for a microchip. However given that there are billions of nanotube lines on a chip, the smallest misalignment would render the chip useless.
This discovery is a big deal. It meant the Stanford team worked out how to control the metallic properties of CNTs and deal with the misalignment, without the need to hunt for them like ‘needles in a haystack’.
This is the key to making CNT transistors suitable for mass production.
Yes, this is early stage research. But all revolutionary products take time.
In the late 1950′s, scientists had only just worked out how to place electrical components in thin sheets of silicon. It was almost twenty years later that enough electric circuits went into a silicon chip to create a whole computer.
It’s a safe bet that the move to carbon nanotube computing will be quicker than the uptake of silicon chips.
Shae Smith
Assistant Editor, Money Weekend
