Work function modulation of bilayer MoS2 nanoflake by backgate electric field effect

We report the work function modulation of bilayer MoS2 nanoflake induced by backgate electric filed. The Fermi level of bilayer MoS2 increased by 115 meV with the backgate bias larger than the threshold voltage. Carrier doping induced by the electric filed was responsible for the variation of work function of MoS2 nanoflake. Meanwhile, asymmetric contact potential drops at electrical contacts were observed, which was consistent with the asymmetric electrical output characteristics. Thermonic field emission theory was used to explain the carrier transport mechanism between Pt and bilayer MoS2, and the larger contact barriers led to the lower carrier mobility. (C) 2013 AIP Publishing LLC.