Spectroscopic investigation of ionic liquid gated van der Waals semiconductors and heterostructures

The fast paced research field of quantum electronics is dominated by the investigation of 2D van der Waals materials. This class of materials consist of different properties ranging from semiconductor, semimetal, superconductor, ferromagnetic and many more. Now with a further possibility to stack different 2D materials to form heterostructures, an unlimited potential of applications have risen. In this thesis we use Field effect transistor geometry with Ionic Liquid (IL) gating to investigate layered transition metal dichalcogenides. Using the spectroscopic capability of IL gating we investigate the band gap of an indirect semiconductor and with high carrier density accumulation drive the indirect semiconductor to emit light. In the second topic we use the ability of creating heterostructure to create an artificial semimetal and characterize its electronic properties. Lastly, we induce superconductivity in a semiconductor using IL and with clever engineering of heterostructure, investigate the fundamental superconducting state