Excitons, quasi particles composed of an electron and a hole, play an important role in optical responses in low-dimensional nanostructures. In this work, we have investigated exciton diffusion in a monolayer MoSe2 encapsulated between flakes of hexagonal boron nitrides (hBN/MoSe2/hBN). Through PL imaging and numerical solving the 2D diffusion equation, we revealed that temperature dependence of exciton mobility in the hBN/MoSe2/hBN shows non-saturating increase at low temperature, which is qualitatively different from those of quantum wells composed of compound semiconductors. Ultraflat structure of monolayer MoSe2 in the hBN/MoSe2/hBN probably leads to the suppression of charged-impurity scattering and surface-roughness scattering.
@article{arxiv.2004.13267,
title = {Exciton diffusion in a hBN-encapsulated monolayer MoSe2},
author = {T. Hotta and S. Higuchi and A. Ueda and K. Shinokita and Y. Miyauchi and K. Matsuda and K. Ueno and T. Taniguchi and K. Watanabe and R. Kitaura},
journal= {arXiv preprint arXiv:2004.13267},
year = {2020}
}