Ultrafast Interlayer Charge Transfer between Bilayer PtSe<sub>2</sub> and Monolayer WS<sub>2</sub>
Pengzhi Wang, Dawei He, Yongsheng Wang, Xiaoxian Zhang, Xiaoyue He, Jiaqi He, Hui Zhao
Abstract
Interlayer charge transfer (CT) between PtSe2 and WS2 is studied experimentally. Layer-selective pump–probe and photoluminescence quenching measurements reveal ultrafast interlayer CT in the heterostructure formed by bilayer PtSe2 and monolayer WS2, confirming its type-II band alignment. The CT facilitates the formation of the interlayer excitons with a lifetime of several hundred ps to 1 ns, a diffusion coefficient of 0.9 cm2 s–1, and a diffusion length reaching 200 nm. These results demonstrate the integration of PtSe2 with other materials in van der Waals heterostructures with novel charge-transfer properties and help develop fundamental understanding on the performance of various optoelectronic devices based on heterostructures involving PtSe2.