A*STAR Develops Production Method For 2D MoS2
One-step sputtering can grow high quality monolayer films at wafer scale
Researchers at Singapore's Agency for Science, Technology and Research (A*STAR) have now developed a method for creating large areas of atom-thin 2D materials for use in electronic devices.
Shijie Wang from the A*STAR Institute of Materials Research and Engineering and his collaborators have now demonstrated a technique for creating a single atomic layer of the 2D compound semiconductor MoS2.
"Traditional mechanical exfoliation methods for obtaining 2D materials have limited usefulness in commercial applications, and all previous chemical methods are incompatible for integration with device fabrication," says Wang. "Our technique is a one-step process that can grow good-quality monolayer films, or few layers of MoS2 films, at wafer scale on various substrates using magnetron sputtering."
The team fired a beam of argon ions at a molybdenum target in a vacuum chamber. This ejected molybdenum atoms from the surface where they reacted with a nearby sulphur vapor. These atoms then assembled onto a heated substrate of either sapphire or silicon. The team found that they could grow monolayer, bilayer, trilayer or thicker samples by altering the power of the argon-ion beam or the deposition time.
They confirmed the quality of their material using a number of common characterisation tools including Raman spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. The researchers also demonstrated the excellent electrical properties of their molybdenum disulfide films by creating a working transistor (see image).
"Our next step in this work will focus on the application of this technique to synthesise other 2D materials and integrate them with different materials for various device applications," says Wang.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering.