A report on the production of complex electronic circuits from the new material was published online this month in the journal Nano Letters; the paper is authored by Han Wang and Lili Yu, graduate students in the Department of Electrical Engineering and Computer Science (EECS); Tomás Palacios, the Emmanuel E. Landsman Associate Professor of EECS; and others at MIT and elsewhere.
Palacios says he thinks graphene and MoS2 are just the beginning of a new realm of research on two-dimensional materials. "It's the most exciting time for electronics in the last 20 or 30 years," he says. "It's opening up the door to a completely new domain of electronic materials and devices."
Like graphene, itself a 2-D form of graphite, molybdenum disulfide has been used for many years as an industrial lubricant. But it had never been seen as a 2-D platform for electronic devices until last year, when scientists at the Swiss university EPFL produced a transistor on the material.
Yi-Hsien Lee, a postdoc in associate professor Jing Kong's group in EECS, found a good way to make large sheets of the material using a chemical vapor deposition process. Lee came up with this method while working with Lain-Jong Li at Academia Sinica in Taiwan and improved it after coming to MIT. Palacios, Wang and Yu then set to producing building blocks of electronic circuits on the sheets made by Lee, as well as on MoS2 flakes produced by a mechanical method, which were used for the work described in the new paper.
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