2023, Enhanced Homogeneity of Moiré Superlattices in Double-Bilayer WSe2 Homostructure, ACS Applied Materials & Interfaces

2023, Enhanced Homogeneity of Moiré Superlattices in Double-Bilayer WSe₂ Homostructure, ACS Applied Materials & Interfaces.

Abstract:

Moiré superlattices have emerged as a promising platform for investigating and designing optically generated excitonic properties. The electronic band structure of these systems can be qualitatively modulated by the interactions between the top and bottom layers, leading to the emergence of new quantum phenomena. However, the inhomogeneities present in atomically thin bilayer moiré superlattices created by artificial stacking have hindered a deeper understanding of strongly correlated electron properties. In this work, we report the fabrication of homogeneous moiré superlattices with controllable twist angles using a 2L-WSe₂/2L-WSe₂ homostructure. By adding extra layers, we provide additional degrees of freedom to tune the optical properties of the moiré superlattices while mitigating the non-uniformity problem. The presence of an additional bottom layer acts as a buffer, reducing the inhomogeneity of the moiré superlattice, while the encapsulation effect of the additional top and bottom WSe2 monolayers further enhances the localized moiré excitons. Our observations of alternating circularly polarized photoluminescence confirm the existence of moiré excitons, and their characteristics were further confirmed by theoretical calculations. These findings provide a fundamental basis for studying moiré potential correlated quantum phenomena and pave the way for their application in quantum optical devices.

Keywords: Twisted double-bilayer, moiré superlattice, moiré exciton, circularly polarized photoluminescence, linearly polarized photoluminescence.

Link: https://pubs.acs.org/doi/10.1021/acsami.3c06949

Enhanced Homogeneity of Moiré Superlattices in Double-Bilayer WSe2 Homostructure.pdf