Dynamic tuning of optical absorbance and structural color of VO₂-based metasurface

Vanadium dioxide (VO₂) is an attractive thermal-control material exhibiting low thermal hysteresis and excellent temperature cycling performance. However, the deficiencies including weak spectral shift and narrow-band absorption during insulating-metallic transitions hinder its application in optoelectronics. The transition metal dichalcogenides (TMDs) can provide a promising solution with their high dielectric properties and robust optical coupling. Here, we report a MoS₂/VO₂/Au/Si metasurface and investigate the dynamic tunability of its optical absorbance and structural color upon heating via spectroscopic ellipsometry measurements and numerical simulations. The first-principles calculations reveal that the dielectric absorptions of metallic and insulating VO₂ oppositely response to temperature, closely related to the difference in the transitions of O-2p states. Finite-element simulations reveal that the introduction of MoS₂ nanostructure induces more absorption peaks by 2∼3 and achieves strong absorption in the full wavelength range of visible light. The Fabry-Perot (F-P) resonance is the critical factor for the optimized optical absorption. The structural color is sensitive to environmental perturbations at high-ε state of VO₂, lower oblique incidence angles, and heights of MoS₂. This work seeks to facilitate the spectral modulation of phase change metamaterials and can be extended to photoelectric detection and temperature sensing applications.