Andras Kis

Electrical Engineering Institute, Ecole Polytechnique Federale de Lausanne (EPFL),

Lausanne, Switzerland

Monday, March 28, 2011

4:30 p.m.

Cardwell 102

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.

References:

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