Chip-Integrated Photonics

To overcome the physical limitations of vertical light absorption in atomically thin materials, we engineered a device architecture that integrates monolayer MoS₂ directly onto SiN waveguides. This work was a collaborative effort, conducted as a joint project with a Master's student whom I mentored and supervised throughout the research process. By utilizing the evanescent field of light traveling through the waveguide, we achieved a dramatic increase in the overlapping area between the light and the semiconductor, leading to significantly enhanced photoresponsivity compared to traditional vertical illumination. This approach holds promise in optical interconnects for chip-to-chip optical communication and intra-chip electrical computation, providing a scalable path for 2D materials in practical optoelectronic circuits.

The project involved a comprehensive "from A to Z" development cycle:
Design & Simulation: We optimized SiN waveguide dimensions and diffraction gratings using numerical modeling (FDTD, Lumerical) to match the bandgap of MoS₂.
Advanced Microfabrication: We employed LPCVD for SiN growth and dry etching for photonic structures, followed by KOH wet etching to smoothen sidewalls for high-quality flake transfer.
Performance Optimization: We integrated a graphene local gate and hexagonal boron nitride (h-BN) dielectric to achieve low-voltage operation and high-speed switching below 1 ms.