Yuto Kajino, Kohei Sakanashi, Nobuyuki Aoki, Kenji Watanabe, Takashi Taniguchi, Kenichi Oto, Yasuhiro Yamada
Physical Review B 103(24) 2021年6月21日 査読有り
Monolayer materials are strongly affected by their potential fluctuations,
which are induced by an intrinsic corrugation or the surface roughness of the
substrate. We compare the effective exciton-exciton annihilation (EEA) rate
constants of monolayer WS2 on substrates with different surface topographies.
We show that monolayer WS2 on the substrate with atomically flat terraces
displays small effective EEA rate constant deviating from the overall tendency
and multiple exciton decay components, which cannot be accounted for by a
conventional EEA model. To obtain a correct description, we use a quantized EEA
model. The intrinsic EEA rate constant for the flat-terrace substrates
determined by this new model is comparable to that of hBN-encapsulated
monolayer WS2.