WHY THIS MATTERS IN BRIEF
As our understanding of computing improves, it is clear that the post-silicon computing era will be anything but dull.
Over the past few years there have been a growing number of experts voicing concerns that Moore’s Law, and the age of silicon computing, is coming to an end as it gets more difficult and more expensive to grind out smaller and smaller transistor sizes. And that’s despite the fact that we already have 5nm, 1nm, 0.5nm and even virus sized and single atom sized transistors being developed in the labs.
However, despite all the doom mongers about the end of the “golden age of computing” coming to an end there are new staggeringly powerful computing technologies already emerging including quantum computers, that are 100 million times faster than today’s computers, neuromorphic computers that can pack all the power of today’s supercomputers into a package the size of a fingernail and revolutionise AI by learning for themselves, as well as more exotic biological, chemical, DNA computers that have been shown capable of packing the power of all of today’s global computing power into a test tube, and liquid computers. And all that’s for starters.
See how it works
It’s the latter type of computing that’s the subject of another breakthrough that I’m going to discuss in this article, and be warned, it gets techy very fast. In 2017 I wrote about the development of the world’s first liquid transistor, and now a little over a year later another group in the US have created the world’s first “liquid computer chip.”
Invigorating the idea of computers based on fluids instead of silicon, researchers at the National Institute of Standards and Technology (NIST) have shown how “computational logic operations could be performed in a liquid medium by simulating the trapping of ions in graphene floating in a saline solution.” Outside of the computing realm the new discovery might also be useful in applications such as water filtration, energy storage and even sensor technology.
The idea of using a liquid medium for computing has been around for decades, and among their many advantages liquid computers would require very little material and space, and their liquid components could assume any shape, for example, within the human body where they could tag team with DNA computers to help turn the human body into disease fighting supercomputers. And yes, that’s a real thing – already.
NIST’s ion-based transistor and logic operations prototypes are simple in their design and, most crucially, showed for the first time that a special film immersed in liquid can act like a traditional solid silicon-based semiconductor like the hundreds of billions of computer chips used in all of today’s computing devices and gadgets.
As an added benefit the new material can even act like a transistor, the switch that carries out digital logic operations in a computer, and researchers demonstrated that the film could be switched on and off by adjusting the voltage levels in the fluid like those induced by salt concentrations in biological systems.
“Previous devices were much more elaborate and complex,” said NIST theorist Alex Smolyanitsky who led the ground breaking research. “What this ion-trapping approach achieves is conceptual simplicity. In addition the same exact device can act as both a transistor and a memory device – all you have to do is switch the input and output. This is a feature that comes directly from ion trapping.”
The NIST team used a graphene sheet 5.5 by 6.4nm in size that had small holes lined with oxygen atoms in it. These pores resemble something known as “crown ethers” – electrically neutral circular molecules that trap metal ions, while the graphene sheet itself was made up of carbon atoms arranged in hexagons, similar in shape to chicken wire, that conducts electricity and could be used to build electrical circuits. It was this hexagonal design that gave the team the breakthrough they needed and allowed them to create the pores they needed.
The graphene was suspended in water containing potassium chloride, a salt that splits into potassium and sodium ions, and the crown ether pores were designed to trap potassium ions, which have a positive charge and trapping a single potassium ion in each pore prevented the penetration of additional loose ions through the graphene sheet, furthermore that trapping and penetration activity could be tuned by applying different voltage levels across the membrane, which helped the team create logic operations with 0s and 1s – also known as binary operations which are the basis of all today’s computing platforms.
The input-output relationship between these operations also let the team create a NOT logic gate or operation, where the input and output values are reversed. If 0 goes in, for example, then 1 comes out, and vice versa, and by using two graphene sheets rather than just one the team were also able to create an OR (XOR) logic operation.
Furthermore when the team applied just small variations in voltage across the membrane they were able to demonstrate a phenomenon known as “sensitive switching” which meant that it might even be possible to use the ion trapping crown pores to store information and perform sophisticated logic operations in what they called “nanofluidic” computing devices – or what I’ m going to simply call Liquid computers.
With all these advances in computing technology it is also becoming absolutely clear that the end of the silicon computing age is something to be celebrated not feared. And that’s before I tell you about how in 2020 Microsoft will start letting you store your information in DNA storage in the cloud, and how scientists last year managed to store and replay videos from living biological bacterial computers… In the future “computers” won’t just be everywhere, they’ll be powerful on a hitherto unimaginable scale.