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Carrier Dynamics and Transfer across the CdS/MoS2 Interface upon Optical Excitation
Kai Cheng1,2, Han Wang1,3, Junhyeok Bang1,4
1Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180, United States.
The Journal of Physical Chemistry Letters
|July 23, 2020
Summary
Investigating charge transfer in cadmium sulfide (CdS) and molybdenum disulfide (MoS2) heterostructures reveals two mechanisms: slow electron-phonon coupling and a fast interfacial dipole-enabled process. The Cd-terminated interface is most favorable for efficient electron transfer.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Surface Science
Background:
- Carrier dynamics at heterostructure interfaces are crucial for technological applications like photovoltaics and catalysis.
- Understanding charge transfer mechanisms is key to optimizing material performance.
Purpose of the Study:
- To investigate the charge transfer mechanisms between cadmium sulfide (CdS) and molybdenum disulfide (MoS2) using first-principles calculations.
- To identify the factors influencing the efficiency and speed of charge transfer at the CdS/MoS2 interface.
Main Methods:
- Utilizing first-principles time-dependent density functional theory (TD-DFT).
- Analyzing interfacial binding energy to determine interface stability.
- Investigating electron-phonon coupling and interfacial dipole effects.
Main Results:
- Two interdependent charge transfer mechanisms were identified: a slow process attributed to electron-phonon coupling and a fast process enabled by an interfacial dipole.
- The Cd-terminated (001) interface was found to be the most energetically favorable.
- Fast resonant electron transfer was predicted at the Cd-terminated interface.
Conclusions:
- The Cd-terminated (001) CdS/MoS2 interface facilitates efficient charge transfer through a combination of slow and fast mechanisms.
- This interface is a promising candidate for explaining experimentally observed charge transfer phenomena.
- The findings provide insights for designing advanced heterostructure-based devices.
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