Thursday, August 23, 2012

Newcomer: 2d sheet of MoS2 puts Graphene transistors in a corner, watch-out Silicon!

Earlier this year I put together a very quick post on the wonders of graphene. What was left unsaid was all the difficulties that are currently part of graphene including its nearly useless as graphene transistors (for computation) / lack of band gap.

That is not to say that is not still an awesome material, it is.

However while graphene hasn't been the holy grail many had expected, one requirement for the upcoming singularity (or an hypothesis/corollary) is that for every door that the cosmos closes, two must open (and thus knowledge grows exponential). 

And that is why I was very happy to read this article on the "latest new" 2d material, molybdenum disulfide (MoS2).

The latest “new” material, (...) — which has actually been used for decades, but not in its 2-D form — was first described just a year ago by researchers in Switzerland. 





But in that year, researchers at MIT — who struggled for several years to build electronic circuits out of graphene with very limited results (except for radio-frequency applications) — have already succeeded in making a variety of electronic components from MoS2. They say the material could help usher in radically new products, from whole walls that glow to clothing with embedded electronics to glasses with built-in display screens.
(...)
Wang had been struggling to build circuits on graphene for his doctoral thesis research, but found it much easier to do with the new material. There was a “hefty bottleneck” to making progress with graphene, he explains, because that material lacks a bandgap — the key property that makes it possible to create transistors, the basic component of logic and memory circuits. While graphene needs to be modified in exacting ways in order to create a bandgap, MoS2 just naturally comes with one.

The lack of a bandgap, Wang explains, means that with a switch made of graphene, “you can turn it on, but you can’t turn it off. That means you can’t do digital logic.” So people have for years been searching for a material that shares some of graphene’s extraordinary properties, but also has this missing quality — as molybdenum disulfide does.
(...)
Wang and Palacios were able to fabricate a variety of basic electronic devices on the material: an inverter, which switches an input voltage to its opposite; a NAND gate, a basic logic element that can be combined to carry out almost any kind of logic operation; a memory device, one of the key components of all computational devices; and a more complex circuit called a ring oscillator, made up of 12 interconnected transistors, which can produce a precisely tuned wave output.
(...)
- read the full article here, on MITnews.

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