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Ultrafast Interlayer Electron Transfer in Incommensurate Transition Metal Dichalcogenide Homobilayers
Yuanyuan Li1,2, Qiannan Cui2, Frank Ceballos2
1National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei, Anhui 230029, China.
Nano Letters
|October 25, 2017
Summary
Efficient electron transfer occurs between same-material 2D layers in van der Waals homobilayers. This finding is crucial for developing advanced optoelectronic devices using transition metal dichalcogenides like MoSe2, WS2, and WSe2.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Two-dimensional (2D) materials like transition metal dichalcogenides (TMDs) enable van der Waals heterostructures with novel properties.
- Efficient interlayer charge transfer is vital for harnessing emergent properties in these 2D material systems.
- Interlayer charge transfer in heterobilayers is well-studied, but data on homobilayers is scarce.
Purpose of the Study:
- To investigate and quantify interlayer electron transfer in 2D van der Waals homobilayers.
- To explore the potential of homobilayers for enhancing optoelectronic properties in multilayer structures.
- To provide insights into charge transfer dynamics within identical 2D material layers.
Main Methods:
- Fabrication of MoSe2, WS2, and WSe2 homobilayers by manual stacking of exfoliated monolayers.
- Utilizing femtosecond transient absorption spectroscopy to time-resolve photoexcited carrier dynamics.
- Employing a graphene layer as a carrier recombination channel to facilitate transfer measurements.
Main Results:
- Observed electron transfer on a picosecond timescale between MoSe2 monolayers.
- Demonstrated even faster charge transfer in WS2 and WSe2 homobilayers.
- Confirmed efficient interlayer carrier transfer in these same-type 2D material systems.
Conclusions:
- Van der Waals homobilayers exhibit efficient picosecond-timescale interlayer charge transfer.
- These homobilayers can enhance optical absorption in multilayer structures without hindering transport.
- The findings offer valuable understanding for designing 2D material-based heterostructures and devices.
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