Ion-gated high mobility 2D transition metal dichalcogenides transistors

Among various discovered 2D materials, semiconductor transition metal dichalcogenides (TMDs) has the similar intrinsic band gap (1-2 eV) as silicon, which makes them good candidates for electronic and optoelectronic applications. Besides, TMDs are the most promising candidates to explore many-body interaction effects and quantum-correlated phases due to their intrinsic 2D nature, large spin-orbit interaction, and large effective mass carriers. However, high contact resistance, high impurity, and low carrier mobility limit developments of TMDs.
To address these issues, in this thesis, a new revert dry transfer method is introduced, confirming the cleanness of the interface of the device. A new device configuration is designed by using ionic liquid gating for achieving metallic contact which confirms the high quality of the channel. The achieved high-quality transistor allowed us to investigate quantum physics at low temperatures. Chapter 2 introduced the new revert transfer method, as well as the device configuration to achieve the high-quality device. Chapter 3 and Chapter 5 illustrated the SdH oscillations observed in the high-quality sample and quantum limit with Landau filling factor equal to 1 is achieved. Chapter 4 studied the doping asymmetry-dependent K/K valley populations across different layers in four-layer MoS2 system. Chapter 6 investigated the electron-electron interaction in multi-layer TMDs.