Graphene-like material paves way for faster chips

MIT scientists create electronic components on material that answers graphene's main shortcoming.

Researchers at MIT have built complex electronic components from the graphene-like two-dimensional form of molybdenum disulphide, or MoS2.

Graphene, a two-dimensional lattice of carbon atoms, is essentially a single layer of the familiar material graphite. After its discovery in 2004, a new gold rush began as scientists began searching for other two-dimensional materials that might exhibit similarly useful properties.

But while graphene holds much promise in a range of applications, researchers have struggled to put it to use in electronics — except in RF applications — because it has no band gap. This means its on-off ratio is just not high enough for logic transistors. Molybdenum disulphide, on the other hand, has no such issue.

MoS2 has been used in industry for many years, but its two-dimensional form was only characterised a year or so ago.

Tomás Palacios, the Emmanuel E Landsman associate professor of Electrical Engineering and Computer Science at MIT, co-authored a paper in Nano Letters with graduate students Han Wang and Lili Yu, describing the work.

Professor Palacios said in MIT's announcement that new materials such as graphene and MoS2 were just the start of a new realm of 2D materials. "It's the most exciting time for electronics in the past 20 or 30 years," he said. "It's opening up the door to a completely new domain of electronic materials and devices."

According to the announcement, 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.

One potential application is in flat screens for TVs and computer monitors, but Palacios sees potential for a whole new range of applications, such as glowing walls of light, or mobile phone antennae that are incorporated into the material of the phone, or even woven into fabric.

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