Near-field visualization of charge transfer at MoSe₂/WSe₂ lateral heterojunction

Abstract

Lateral heterojunction (HJ) of two-dimensional transition metal dichalcogenides has various optoelectronic applications that utilize in-plane charge separation. However, it has been difficult to identify charge transfer characteristics at HJ due to the limited spatial resolution of optical spectroscopy. In this study, near-field scanning optical microscopy is used to directly image the exciton separation occurring at the lateral MoSe2/WSe2 HJ, which was found to be ∼370 nm in spatial width. Efficient charge separation at HJ was confirmed by inspecting local variations of trion and exciton emissions of MoSe2 and WSe2.