Coupling of photonic crystal cavity and interlayer exciton in heterobilayer of transition metal dichalcogenides

The advent of van der Waals heterostructures marks the emergence of a new class of synthetic materials with novel properties that are unattainable in their constituent materials. The 2D architecture of these layered materials makes them naturally suited for integration with a wide variety of planar nanophotonic cavities for next-generation low-power optoelectronic devices and explorations of fundamental physical effects in these new systems. Here, we report the coupling of the interlayer exciton in a transition metal dichalcogenide heterobilayer with a gallium phosphide photonic crystal defect cavity. The exciton-cavity coupling is found to be in the weak regime, resulting in ∼15-fold increase in the photoluminescence intensity for interlayer exciton in resonance with the cavity. Simulation results suggest that the increased intensity stems from a Purcell enhancement of ∼60. The order of magnitude enhancement of the photoluminescence yield offsets the low oscillator strength of the interlayer exciton, adding a new tool for probing the underlying physics of this excitonic system.