Exciton Diffusion in hBN-encapsulated Monolayer MoSe2

Optical responses from two-dimensional semiconductors, such as monolayer transition metal dichalcogenides (TMDs), are dominated by excitonic effects due to strong Coulomb interaction between electrons and holes. Diffusion of excitons is, therefore, one of the most important processes to understand optical responses in 2D semiconductors. In this work, we have prepared a high-quality TMD, monolayer MoSe 2 encapsulated by hBN flakes (hBN/MoSe2/hBN), and investigated intrinsic exciton diffusion at various temperatures ranging from 10 ∼ 300 K. We found that Exciton mobility in hBN/MoSe 2 /hBN monotonically increases as temperature decreases, and mobility at 10 K reaches over 104 cm2V−1s−1.