Modulating Interlayer Interaction of van der Waals Semiconductors for Tunable Quantum Optics

Abstract: The optical characteristics of van der Waals (vdW) layered semiconductors exhibit significant sensitivity to the layer number, offering a means to tune their optical properties through the manipulation of interlayer coupling. Our study demonstrates the active control of interlayer coupling strength in multilayer MoS2 and stacked bilayer ReS2 through electrochemical ion intercalation and varying stacking twist angle, respectively. Specifically, we show that interlayer coupling strength in multilayer MoS2 can be actively controlled through electrochemical ion intercalation [1]. Through the ion intercalation, multilayer MoS₂ displayed a hundredfold increase in PL intensity and stable valley polarization, achieving 55% and 16% degrees of valley polarization at 3 K and room temperature, respectively. The persistent valley polarization at room temperature, due to interlayer decoupling and trion dominance opens up potential applications in valley-selective optoelectronics. We also show that the bandgap energy and interlayer coupling strength of twisted bilayer (tBL) ReS2 can be continuously modulated by the twist angle [2]. By controlling the twist angle between 0° and 10°, the exciton energy of tBL ReS2 is tuned over the whole range between the exciton energies of intrinsic monolayer and bilayer ReS 2 . The strong modulation of interlayer coupling by the twist angle in tBL ReS2 is attributed to the low symmetry of the 1T’ structure and in-plane anisotropy of the ReS2 lattice. These findings demonstrate the enhanced tunability of twist-controlled electronic structure in anisotropic 2D materials, offering new pathways for designing reconfigurable quantum materials.
References
[1] M. Jo et al. Adv. Mater., 36 (2024), pp. 2407997.
[2] K. P. Dhakal et al., Adv. Sci., 12 (2025), pp. 2500411.