Potential landscape engineering in two-dimensional transition metal dichalcogenides: towards hybrid optical-electrical quantum dots*

Monolayer transition metal dichalcogenides (TMDCs) have attracted recent interest due to their unique excitonic and electronic properties. As gapped, semiconducting counterparts to graphene, they show particularly strong excitonic effects, which can be exploited both in pure monolayer devices, as well as in van der Waals heterostructures where the TMDC is encapsulated between layers of insulating hexagonal boron nitride (hBN). In this work, we discuss progress towards a unique platform that exploits the strong excitonic binding energies of the TMDCs to create a hybrid, electrically controlled yet optically active quantum dot device. Further, we report on recent experiments showing optically induced current from hole-doped molybdenum diselenide to graphite or metal electrodes across over 90nm of hBN, indicating a limitation of hBN encapsulation for hybrid optical-electronic devices in TMDCs along with a method for unipolar charge injection into uncontacted TMDC layers. Finally, we discuss methods for making tunable excitonic potential landscapes in TMDC heterostructures via modulation of the dielectric environment in reconfigurable moiré structures.