Electric Field Tunable Ultrafast Interlayer Charge Transfer in Graphene/WS₂ Heterostructure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Optoelectronics

Background:

• Van der Waals heterostructures offer tunable properties for optoelectronics.
• Two-dimensional materials enable novel device functionalities.

Purpose of the Study:

• Investigate photoinduced charge transfer dynamics in graphene/WS2 heterostructures.
• Understand the mechanisms governing ultrafast interlayer charge transfer.
• Explore the influence of external electric fields on carrier dynamics.

Main Methods:

• Time-dependent density functional theory molecular dynamics simulations.
• Analysis of vibrational modes and their correlation with charge transfer.
• Investigating carrier transfer rates at the heterointerface.

Main Results:

• Hole transfer from graphene to WS2 is twice as fast as electron transfer.
• Interlayer charge transfer is linked to vibrational modes of both materials.
• External electric fields effectively modulate carrier dynamics.
• Carrier transfer rate depends on donor-acceptor state coupling and relaxation processes.

Conclusions:

• Provides fundamental insights into ultrafast charge transfer in 2D heterostructures.
• Highlights the role of vibrational modes and electric fields in carrier dynamics.
• Suggests potential for enhanced photovoltaic device performance through controlled charge transfer.