Enhancing Light-Matter Interaction by Coupling MoSe₂/WSe₂ Van der Waals Heterostructures to Confined Photonic Resonances

Semiconductor heterostructures are essential building blocks for numerous electronic and optoelectronic devices such as lasers, light-emitting diodes, solar cells, and transistors. Layer-stacking of atomically thin transition metal dichalcogenides (TMDC) has opened up new opportunities for novel light-emitting phenomena. Confined photonic resonances are particularly of interest in enhancing light-matter interaction because they are able to localize light significantly both in the spatial and temporal domain. In this work, we incorporate heterostructures of monolayer molybdenum diselenide and tungsten diselenide within two different monolithic photonic structures. We investigate exciton hybridization in two devices. Device one is based on planar Bragg mirror microcavities and device two utilizes Tamm-plasmon modes. For both devices enhanced photoluminescence is observed and polariton formation is demonstrated via the anti-crossing in the measured energy-momentum dispersion curve. Our results pave the way for novel polariton devices based on TMDC van der Waals heterostructures, where Berezinskii-Kosterlitz-Thouless (BKT) transition of this 2D low-mass boson gas can be realized.