Year-End Tech News: Stanene and Nanoparticle Ink

3d.printingThe year of 2013 was also a boon for the high-tech industry, especially where electronics and additive manufacturing were concerned. In fact, several key developments took place last year that may help scientists and researchers to move beyond Moore’s Law, as well as ring in a new era of manufacturing and production.

In terms of computing, developers have long feared that Moore’s Law – which states that the number of transistors on integrated circuits doubles approximately every two years – could be reaching a bottleneck. While the law (really it’s more of an observation) has certainly held true for the past forty years, it has been understood for some time that the use of silicon and copper wiring would eventually impose limits.

copper_in_chips__620x350Basically, one can only miniaturize circuits made from these materials so much before resistance occurs and they are too fragile to be effective. Because of this, researchers have been looking for replacement materials to substitute the silicon that makes up the 1 billion transistors, and the one hundred or so kilometers of copper wire, that currently make up an integrated circuit.

Various materials have been proposed, such as graphene, carbyne, and even carbon nanotubes. But now, a group of researchers from Stanford University and the SLAC National Accelerator Laboratory in California are proposing another material. It’s known as Stanene, a theorized material fabricated from a single layer of tin atoms that is theoretically extremely efficient, even at high temperatures.

computer_chip5Compared to graphene, which is stupendously conductive, the researchers at Stanford and the SLAC claim that stanene should be a topological insulator. Topological insulators, due to their arrangement of electrons/nuclei, are insulators on their interior, but conductive along their edge and/or surface. Being only a single atom in thickness along its edges, this topological insulator can conduct electricity with 100% efficiency.

The Stanford and SLAC researchers also say that stanene would not only have 100%-efficiency edges at room temperature, but with a bit of fluorine, would also have 100% efficiency at temperatures of up to 100 degrees Celsius (212 Fahrenheit). This is very important if stanene is ever to be used in computer chips, which have operational temps of between 40 and 90 C (104 and 194 F).

Though the claim of perfect efficiency seems outlandish to some, others admit that near-perfect efficiency is possible. And while no stanene has been fabricated yet, it is unlikely that it would be hard to fashion some on a small scale, as the technology currently exists. However, it will likely be a very, very long time until stanene is used in the production of computer chips.

Battery-Printer-640x353In the realm of additive manufacturing (aka. 3-D printing) several major developments were made during the year 0f 2013. This one came from Harvard University, where a materials scientist named Jennifer Lewis Lewis – using currently technology – has developed new “inks” that can be used to print batteries and other electronic components.

3-D printing is already at work in the field of consumer electronics with casings and some smaller components being made on industrial 3D printers. However, the need for traditionally produced circuit boards and batteries limits the usefulness of 3D printing. If the work being done by Lewis proves fruitful, it could make fabrication of a finished product considerably faster and easier.

3d_batteryThe Harvard team is calling the material “ink,” but in fact, it’s a suspension of nanoparticles in a dense liquid medium. In the case of the battery printing ink, the team starts with a vial of deionized water and ethylene glycol and adds nanoparticles of lithium titanium oxide. The mixture is homogenized, then centrifuged to separate out any larger particles, and the battery ink is formed.

This process is possible because of the unique properties of the nanoparticle suspension. It is mostly solid as it sits in the printer ready to be applied, then begins to flow like liquid when pressure is increased. Once it leaves the custom printer nozzle, it returns to a solid state. From this, Lewis’ team was able to lay down multiple layers of this ink with extreme precision at 100-nanometer accuracy.

laser-welding-640x353The tiny batteries being printed are about 1mm square, and could pack even higher energy density than conventional cells thanks to the intricate constructions. This approach is much more realistic than other metal printing technologies because it happens at room temperature, no need for microwaves, lasers or high-temperatures at all.

More importantly, it works with existing industrial 3D printers that were built to work with plastics. Because of this, battery production can be done cheaply using printers that cost on the order of a few hundred dollars, and not industrial-sized ones that can cost upwards of $1 million.

Smaller computers, and smaller, more efficient batteries. It seems that miniaturization, which some feared would be plateauing this decade, is safe for the foreseeable future! So I guess we can keep counting on our electronics getting smaller, harder to use, and easier to lose for the next few years. Yay for us!

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The Future of Computing: Graphene Chips and Transistors

computer_chip4The basic law of computer evolution, known as Moore’s Law, teaches that within every two years, the number of transistors on a computer chip will double. What this means is that every couple of years, computer speeds will double, effectively making the previous technology obsolete. Recently, analysts have refined this period to about 18 months or less, as the rate of increase itself seems to be increasing.

This explosion in computing power is due to ongoing improvements in the field of miniaturization. As the component pieces get smaller and smaller, engineers are able to cram more and more of them onto chips of the same size. However, it does make one wonder just how far it will all go. Certainly there is a limit to how small things can get before they cease working.

GrapheneAccording to the International Technology Roadmap for Semiconductors (ITRS), a standard which has been established by the industry’s top experts, that limit will be reached in 2015. By then, engineers will have reached the threshold of 22 nanometers, the limit of thickness before the copper wiring that currently connect the billions of transistors in a modern CPU or GPU will be made unworkable due to resistance and other mechanical issues.

However, recent revelations about the material known as graphene show that it is not hampered by the same mechanical restrictions. As such, it could theoretically be scaled down to the point where it is just a few nanometers, allowing for the creation of computer chips that are orders of magnitude more dense and powerful, while consuming less energy.

IBM-Graphene-ICBack in 2011, IBM built what it called the first graphene integrated circuit, but in truth, only some of the transistors and inductors were made of graphene while other standard components (like copper wiring) was still employed. But now, a team at the University of California Santa Barbara (UCSB) have proposed the first all-graphene chip, where the transistors and interconnects are monolithically patterned on a single sheet of graphene.

In their research paper, “Proposal for all-graphene monolithic logic circuits,” the UCSB researchers say that:

[D]evices and interconnects can be built using the ‘same starting material’ — graphene… all-graphene circuits can surpass the static performances of the 22nm complementary metal-oxide-semiconductor devices.

graphene_transistormodelTo build an all-graphene IC (pictured here), the researchers propose using one of graphene’s interesting qualities, that depending on its thickness it behaves in different ways. Narrow ribbons of graphene are semiconducting, ideal for making transistors while wider ribbons are metallic, ideal for gates and interconnects.

For now, the UCSB team’s design is simply a computer model that should technically work, but which hasn’t been built yet. In theory, though, with the worldwide efforts to improve high-quality graphene production and patterning, it should only be a few years before an all-graphene integrated circuit is built. As for full-scale commercial production, that is likely to take a decade or so.

When that happens though, another explosive period of growth in computing speed, coupled with lower power consumption is to be expected. From there, subsequent leaps are likely to involve carbon nanotubes components, true quantum computing, and perhaps even biotechnological circuits. Oh the places it will all go!