Computing has an enormous impact on the world. While computers are behind the mechanization of many global industries, the planet’s millions of computers also use a massive amount of energy. On top of that, they also use numerous precious metals including gold, platinum and silicon. However, a Swiss team may have found an alternative to silicon which could result in smaller, more flexible and less energy hungry microchips – not to mention a possible name change for Silicon Valley.
The Swiss team’s chip does not use silicon, but molybdenite (MoS2) a dark-coloured, naturally occurring mineral that is able to be used in much thinner layers. Currently used as a strengthening agent in plastic, molybdenite is abundant in the natural word. Speaking to the BBC, Prof Andras Kis, the director of the Laboratory of Nanoscale Electronics and Structures (LANES) in Lausanne, said that his team’s research could transform the world of computing. “[Currently] there is something like 19 million metric tonnes around,” Prof Kis said in an interview. “You can just go on some websites on the internet and buy a 1cm by 1cm crystal for around $100 [£64].” Kis’s team built a prototype microchip circuit on to a sliver of molybdenite upon which they attached up to six serial transistors allowing them to carry out simple logic operations. Although basic, it showed that microchips could be made that are thinner than their silicon counterparts.
“The problem with silicon is that you cannot make very thin things from it because it is very reactive,” Kis added. “The surface likes to oxidise – it likes to bind with oxygen… and that makes its electrical properties degrade when you want to make a very thin film.”
Very thin is an understatement. Currently silicon layers in microchips can be as thin as two nanometres, however a layer of molybdenite can be a mere three atoms thick. By being thinner, the microchips can also be smaller which means they will automatically dissipate less (and spend) power. Molybdenite is also incredibly flexible, which could lead to electronics being created that are able to be moulded to any surface – including skin. Silicon, in comparison, is prone to shattering like glass if you bend it. Of course, Kis’s team aren’t the first ones to create a silicon-free microchip as other teams have been researching the same thing using graphene, but molybdenite has an advantage. Graphene has to be cooled to 70 Kelvin before it can amplify electronic signals, but molybdenite can do it at room temperature.
“If you look at the circuits in computers, for example, you have millions of transistors connected in series doing some kind of calculation,” said Prof. Kis. “The important thing is that the signal that goes into the processor doesn’t get reduced as a consequence of the operation, because then you’d lose your electrical signal in the chip, so it has to be constantly amplified. Silicon can do this and so can molybdenite, but graphene can only do it at very low temperatures.” Despite the technological breakthrough, there is a downside – Kis’s team believe they are 10-20 years away from making the technology commercially viable.
Via BBC News