Room temperature magnetron sputtering and laser annealing of ultrathin MoS2 for flexible transistors. (February 2019)

• Record Type: Journal Article
• Authors: Sirota, Benjamin; Glavin, Nicholas; Voevodin, Andrey A.
• Is Part Of: Vacuum. Volume 160(2019)
• Page Start: 133
• Page End: 138
• Publication Date: 2019-02
• Subjects: Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2018.10.077
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Pulsed magnetron sputtering and subsequent laser annealing represents a scalable route for producing two-dimensional (2D) semiconducting grade molybdenum disulfide (MoS2 ) directly on the surface of flexible polymer substrates. In this study the room temperature magnetron sputtering was used to deposit 10 nm thick, amorphous MoS2 films on flexible PDMS and rigid SiO2 /Si substrates. The films were then crystallized using an ultrafast 248 nm pulsed laser to produce polycrystalline 2HMoS2 over large areas. Raman and XPS analysis confirmed that pulsed laser annealing with 1.04 mJ/mm 2 energy density induced hexagonal 2H crystal structure, while preserving MoS2 chemical composition and avoiding formation of oxide phases or damage to the temperature-sensitive polymer surface. Top-gated field effect transistor (FET) devices with laser annealed sputter grown MoS2 were directly fabricated on PDMS surfaces. Oxygen substitution of sulfur in sputter grown MoS2 and polycrystallinity of laser annealed 2HMoS2 films resulted in reduced mobility values, when compared to mechanically exfoliated and chemical vapor deposition grown single crystal 2D MoS2 . However, the described approach is intrinsically scalable and provides a direct growth route for the fabrication of 2D transition metal dichalcogenide semiconducting devices on the surface of flexible and stretchable polymers. Highlights: Conversion of amorphous MoS2 to polycrystalline using laser annealing. Minimal oxidation occurred as measured by XPS and Raman. Improvement in electrical properties. Flexible field effect transistor.