Demonstration of Direct Band Gap and Valley Polarization of multilayer MoS2

Jeongyong Kim^1*

¹Energy Science, Sungkyunkwan University, Suwon, Korea

* Presenter:Jeongyong Kim, email:j.kim@skku.edu

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. We demonstrate the active control of interlayer coupling strength in multilayer MoS2 through electrochemical ion intercalation. 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.

Keywords: Valley polarization, Bandgap crossover, Photoluminescence, Ion intercalation, Interlayer coupling