Publication

Two-dimensional optical modulators often suffer from low efficiency due to defect-induced losses and light–matter interaction strength. Here we show that edge defects in solution-processed WSe₂ nanosheets, arising from metallic 1 T domains at the edges and semiconducting 2H interiors, can be dynamically saturated through carrier trap filling. By tuning the nanosheet lateral size and applying optical or electrical excitation, defect states are progressively saturated, reducing nonradiative recombination and reshaping the carrier distribution within the film.  

This process enhances the intrinsic excitonic response, as reflected by the improved photoluminescence peak modulation efficiencies of 0.025 eV·V⁻¹ (electro-optic) and 0.1 eV·mW⁻¹ (opto-optic). More importantly, the carrier redistribution and trap filling induce changes in the complex refractive index (Δn + iΔk) through defect-state modulation and free-carrier (Drude-like) effects.

Integrated with lithium-niobate-on-insulator micro-ring resonators, solution-processed WSe₂ films deliver efficient C-band (1530–1565 nm) modulation with a tuning efficiency of 1.84 × 10⁻⁵pm⁻¹·mW·m².  Time-resolved measurements further confirm fast dynamics, with ~48.1 ns rise, ~79.4 ns fall, and sustained 200 ns operation ( ~ 5 MHz), which surpasses prior 2D-material OO modulators, establishing engineered defect regulation as a scalable route toward high-performance photonic integration.

Researcher/Author: 

Lead Principal Investigator – Prof Aaron Voon-Yew Thean

Researchers – Jianan Li, Zefeng Xu, Yuan Chen, Chenxuan Zeng, Jie Yang, Jin Feng Leong, Maheswari Sivan, Baoshan Tang, Zhe Wang, Yuan Gao, Hong-Lin Lin, Arjun Kesav Mugilvannan, Evgeny Zamburg, Aaron Danner, Cheng-Wei Qiu, Goki Eda 

Published in: 

nature communications

Date of Conference : 19-23 April 2026

Date added to nature communications : 4 June 2026

To download the paper, please proceed to:  

DOI:  

https://www.nature.com/articles/s41467-026-73576-1