Ultrafast Charge Separation and Indirect Exciton Formation in a MoS 2 –MoSe 2 van der Waals Heterostructure

We observe subpicosecond charge separation and formation of indirect excitons a van der Waals heterostructure formed by molybdenum disulfide and molybdenum diselenide monolayers. The sample is fabricated by manually stacking monolayer MoS2 and MoSe2 flakes prepared by mechanical exfoliation. Photoluminescence measurements confirm the formation of an effective heterojunction. In the transient absorption measurements, an ultrafast laser pulse resonantly injects excitons in the MoSe2 layer of the heterostructure. Differential reflection of a probe pulse tuned to the MoS2 exciton resonance is immediately observed following the pump excitation. This proves ultrafast transfer of electrons from MoSe2 to MoS2 layers,…

• DO
  Division of Materials Research

  Award: 0954486
• OO
  Office of Integrative Activities

  Award: IIA-1430493
• OO
  Office of Experimental Program to Stimulate Competitive Research

  Award: EPS-0903806