New material could lead to thin, flexible, wall-sized TVs

Wang et al. / MIT

An optical-microscope image shows a complex integrated circuit, called a JK flip-flop circuit, a basic logic device, made on a piece of molybdenum disulfide by the MIT team.

Sheets of material commonly used as an industrial lubricant — just one-molecule thick — may usher in a new era of thin, flexible, and transparent electronics, according to a researcher at the forefront of the technology.
The material, molybdenum disulfide, is similar to wonder material graphene that researchers have been working with since 2004. Unlike graphene, the molybdenum disulfide has a property called a bandgap.
“A bandgap is the most important property for any material to be useful in electronic applications,” Tomás Palacios, an associate professor of electrical engineering and computer science at the Massachusetts Institute of Technology, told me Friday.
“A bandgap is the property that allows a transistor, which is basically a switch, to either let the current flow or stop.”
A working switch means researchers can use the one-molecule thick sheets of the material to build "a new generation of electronic circuits," Palacios added.
Examples of possible gadgets range from living room wall-sized TVs that sip electricity to cars or buildings covered in sensors. The material could be used to weave the antenna and other circuitry of a cellphone into clothing — meaning you could essentially wear your phone.
The material could even be applied to glass, producing displays on an office window or eyeglasses.
Asked if this was in line with the Google glasses concept generating buzz of late, Palacios said, "It would definitely help to implement that concept."
He is particularly excited about the potential of the material to serve as a supremely sensitive chemical sensor. Since the current flowing on the device is at the surface, anything that happens at the surface is going to affect the current.
"We are working on chemical sensors with molybdenum disulfide that should have much higher sensitivity than conventional sensors," he said. "They should allow us to detect single molecules of a given chemical component."
One could imagine that would be useful for anyone concerned about the spread or use of chemical weapons, for example.
Before any of this is possible, though, the researchers first need to be able to create the molybdenum disulfide sheets at a practical scale.
The team currently gets small pieces via what’s known as the Scotch tape method, in which an adhesive is pressed against a molybdenum disulfide crystal and peeled off carefully.
This sticks a few pieces of molybdenum disulfide to the adhesive, which is then pressed onto a piece of silicon.
"If we are very lucky, we will get a few flakes of molybdenum disulfide transferred from the scotch tape to the silicon wafer,” Palacios said. "And then we fabricate our devices."
The low-tech approach, he noted, is good for initial demonstrations of the material's potential, which is presented in a paper this month in the journal Nano Letters. 
A more efficient fabrication process is required for commercialization of these potential technologies.
Palacios and colleagues are working on one such method via a process known as chemical vapor deposition. Initial results, he said, will be announced shortly.
Source:NBCNEWS