Directional Exciton-Energy Transport in a Lateral Heteromonolayer of WSe<sub>2</sub>-MoSe<sub>2</sub>.
basic_science · Level V
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- Record sourced from PubMed, PMID 35481755.
- Also identified by DOI 10.1021/acsnano.2c01890.
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Abstract
Controlling the direction of exciton-energy flow in two-dimensional (2D) semiconductors is crucial for developing future high-speed optoelectronic devices using excitons as the information carriers. However, intrinsic exciton diffusion in conventional 2D semiconductors is omnidirectional, and efficient exciton-energy transport in a specific direction is difficult to achieve. Here we demonstrate directional exciton-energy transport across the interface in tungsten diselenide (WSe<sub>2</sub>)-molybdenum diselenide (MoSe<sub>2</sub>) lateral heterostructures. Unidirectional transport is spontaneously driven by the built-in asymmetry of the exciton-energy landscape with respect to the heterojunction interface. At excitation positions close to the interface, the exciton photoluminescence (PL) intensity was substantially decreased in the WSe<sub>2</sub> region and enhanced in the MoSe<sub>2</sub> region. In PL excitation spectroscopy, it was confirmed that the observed phenomenon arises from lateral exciton-energy transport from WSe<sub>2</sub> to MoSe<sub>2</sub>. This directional exciton-energy flow in lateral 2D heterostructures can be exploited in future optoelectronic devices.