CLASSICAL AND QUANTUM TRANSPORT PROPERTIES OF SEMICONDUCTING TRANSITION METAL DICHALCOGENIDE NANOSHEETS

Abstract

In the past few years, physics of two-dimensional (2D) cyrstals have attracted considerable attention due to their unique band structure, symmetry and spin-orbit coupling. In this thesis, we investigate the charge transport properties of semiconducting 2D nanosheets in the classical and quantum mechanical regimes. Charge transport properties were studied in the metallic conduction regime using ionic gating. First, we show that the dual gating allows access to a wide range of carrier densities in 2D MoS2 crystals. High density doping was found to lead to dramatic changes in the transport properties with a clear crossover from insulating to metallic conduction. Second, we observe a crossover form weak localization to weak anti-localization in bilayer MoS2 with increasing magnetic fields. We show that the crossover can be explained by electric field induced symmetry breaking and breaking of spin-rotational symmetry. Finally, we study hole transport and hole spin dynamics in bilayer WSe2.