Dielectric environment engineering via 2D material heterostructure formation on hybrid photonic crystal nanocavity

TL;DR

This paper demonstrates that stacking 2D material heterostructures on hybrid photonic crystal nanocavities allows for active, post-fabrication dielectric environment engineering, enhancing cavity performance and enabling reconfigurable nanophotonic devices.

Contribution

It introduces a novel method of forming 2D heterostructures on nanocavities to actively control the dielectric environment and improve device functionalities.

Findings

High-Q nanocavities are robust under sequential 2D flake stacking.

Coupling MoTe₂ enhances photoluminescence and reduces emission lifetime.

Encapsulation with hBN increases cavity Q factor significantly.

Abstract

Hybrid integration of two-dimensional (2D) materials with nanophotonic platforms has enabled compact optoelectronic devices by leveraging the unique optical and electronic properties of atomically thin layers. While most efforts have focused on coupling 2D materials to pre-defined photonic structures, the broader potential of 2D heterostructures for actively engineering the photonic environment remains largely unexplored. In our previous work, we employed single types of 2D material and showed that even monolayer flakes can locally induce high-$Q$ nanocavities in photonic crystal (PhC) waveguides through effective refractive index modulation. Here, we extend this concept by demonstrating that further transferring of 2D material flakes onto the induced hybrid nanocavity to form heterostructures enable more flexibility for post-fabrication dielectric environment engineering of the cavity. We show that the high-$Q$ hybrid nanocavities remain robust under sequential flake stacking. Coupling optically active MoTe$_{2}$ flake to these cavities yields enhanced photoluminescence and reduced emission lifetimes, consistent with Purcell-enhanced light-matter interactions. Additionally, encapsulation with a top hBN layer leads to a significant increase in the cavity $Q$ factor, in agreement with numerical simulations. Our results show that these heterostructure stacks not only preserve the cavity quality but also introduce an additional degrees of control -- via flake thickness, refractive indices, size and interface design -- offering a richer dielectric environment modulation landscape than what is achievable with monolayers alone, providing a versatile method toward scalable and reconfigurable hybrid nanophotonic systems.