Localized Optoelectronic Responses in the Reconstructed Moiré Superlattice of Twisted Bilayer MoS₂

In a reconstructed moiré superlattice formed by semiconducting transition metal dichalcogenides (TMDs), a local atomic stacking configuration within a supercell is anticipated to generate distinct band structures along different highly symmetric orientations, resulting in a localized optoelectronic response within the nanoscale domain structure. Herein, by using photosensitive frequency modulation Kelvin probe force microscopy (FM-KPFM), we investigated the localized optoelectronic response of twisted bilayer MoS 2 with a small twist-angle of approximately 0.17°. We identified two types of superstructures with potential domain periodicities of 110 and 190 nm, which exhibit excitation photon energy and power density-dependent contact potential difference (CPD) responses differing from those of the rigid supercells. Additionally, local atomic stacking configuration-induced domains exhibit moiré potential depth and surface photovoltage (SPV) response depending on the excitation photon energy and power density. Our study provides new insights into the optoelectronic properties of TMDs superlattice and is expected to facilitate the design of advanced twistronic devices.