Electrical Engineering Institute, Ecole Polytechnique Federale de Lausanne (EPFL),
Monday, March 28, 2011
Semiconducting Alternative to Graphene: Single-Layer MoS2
After quantum dots, nanotubes and nanowires, two-dimensional materials in the shape of sheets with atomic-scale thickness represent the newest addition to the diverse family of nanoscale materials. The most widely studied two-dimensional material to date is graphene because of its rich physics, high-mobility and wide variety of potential applications. Pristine graphene is however not a semiconductor and the lack of band gap is a serious problem in many applications, for example in electronics.
I will show here our work on a material similar to graphene – single layer MoS2, a direct-gap semiconductor. We have exfoliated single layers 6.5 Angstrom thick from bulk crystals of semiconducting MoS2, using the micromechanical cleavage technique commonly used for the production of graphene. Our nanolayers are mechanically and chemically stable under ambient conditions. We have fabricated transistors based on single-layer MoS2 which demonstrate that this material has several advantages over silicon or graphene for potential applications in electronics.
Being a thin, transparent semiconducting material, MoS2 monolayers also present a wealth of new opportunities in areas that include mesoscopic physics, optoelectronics and energy harvesting.
1. B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, and A. Kis. Single-layer MoS2 transistors. Nature Nanotechnology 6, 147, 2011.
2. M.M. Benameur, B. Radisavljevic, J.S. Heron, S. Sahoo, H. Berger, and A. Kis. Visibility of dichalcogenide nanolayers. Nanotechnology 22, 125706, 2011