Issue Date: June 18, 2012
Laser Method Yields Single-Atom-Thick Molybdenum Sulfide
A laser-based technique can make one-atom-thick layers of molybdenum disulfide, possibly enabling large-scale production of electronics based on the semiconductor (Nano Lett., DOI: 10.1021/nl301164v). Single-atom-thick MoS2 has a band gap—the energy difference between a conducting state and a nonconducting one—greater than silicon’s. As a result, transistors made from the material would require less power to turn off than silicon-based ones do. Researchers think the flexible and transparent material could be an alternative to silicon in bendable displays and electronics. Currently, methods to make single-atom sheets of MoS2, such as exfoliating chunks of the material using sticky tape, are too cumbersome for large-scale production. Andres Castellanos-Gomez, a researcher at Delft University of Technology, in the Netherlands, found that when he shined a 10-mW green laser beam on multilayer MoS2 flakes, the material’s top layers vaporized. He and his colleagues used optical microscopy, atomic force microscopy, and Raman spectroscopy to confirm that the remaining material was a single layer of atoms. They produced transistors using the material and found that the devices had switching speeds similar to those of transistors made from exfoliated single-layer flakes.
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