Abstract
Abstract
We demonstrate anisotropic exciton drift-diffusion in a WS2x
Se(2–2x) alloy monolayer with a gradually changing exciton energy caused by the spatial variation in the chalcogen composition ratio. The photoluminescence (PL) images under isotropic laser excitation are extended toward the lower exciton energy side. Moreover, the degree of asymmetry in the PL image increases at the positions with a steep exciton energy gradient. The anisotropy in the PL images and its correlation with the exciton energy gradient are reproduced considering the exciton kinetics obeying a drift-diffusion equation. The findings may support the development of excitonic devices using transition metal dichalcogenides.
Funder
Core Research for Evolutional Science and Technology
Japan Science and Technology Agency
Japan Society for the Promotion of Science
Subject
General Physics and Astronomy,General Engineering