Efficient interlayer electron transfer in a MoTe 2 /WS 2 /MoS 2 trilayer heterostructure

Pan, Shudi; Valencia-Acuna, Pavel; Kong, Weijin; Liu, Jianhua; Ge, Xiaohui; Xie, Wanfeng; Zhao, Hui

doi:10.1063/5.0047909

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Efficient interlayer electron transfer in a MoTe 2 /WS 2 /MoS 2 trilayer heterostructure

Pan, Shudi·Valencia-Acuna, Pavel·Kong, Weijin·Liu, Jianhua·Ge, Xiaohui·Xie, Wanfeng·Zhao, Hui

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Abstract

Electron transfer and carrier dynamics in MoTe 2 /WS 2 /MoS 2 trilayer heterostructures are investigated by transient absorption and photoluminescence measurements. Monolayer flakes of MoTe 2 , WS 2 , and MoS 2 are obtained by mechanical exfoliation from their bulk crystals and are used to fabricate the heterostructures by a dry-transfer technique. Here, photoluminescence spectroscopic measurements indicate that the recombination of the MoS 2 and WS 2 intralayer excitons is significantly suppressed in the heterostructure, illustrating the efficient interlayer charge transfer processes. Layer-selective time-resolved differential reflectance measurements show that the electrons excited in MoTe 2 can transfer to MoS 2 within 0.3 ps. The transferred electrons show a long lifetime of several hundred picoseconds due to their slow recombination with the spatially separated holes that reside in MoTe 2 . Furthermore, the charge transfer and recombination processes are weakly dependent on the injected carrier density. These results demonstrate the feasibility of constructing van der Waals multilayer heterostructures involving the infrared-sensitive MoTe 2 with emergent properties and provide important information to quantify the performance of MoTe 2 - based devices.

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2D materials 36 MATERIALS SCIENCE Electron transfer Excitons Heterostructures Mechanical exfoliation Optical properties Photoluminescence Pump-probe microscopy

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Pan, Shudi, Valencia-Acuna, Pavel, Kong, Weijin, Liu, Jianhua, Ge, Xiaohui, Xie, Wanfeng, Zhao, Hui. 2021-06-21. Efficient interlayer electron transfer in a MoTe 2 /WS 2 /MoS 2 trilayer heterostructure. https://doi.org/10.1063/5.0047909

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