Sub-µm Hot Carrier Diffusion in 2D MoS₂ on High-κ Metal-Oxide Substrate

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Hot carriers are crucial for efficient photovoltaic and optoelectronic devices.
• Rapid energy dissipation via carrier-phonon scattering and recombination limits hot carrier applications.
• Dielectric engineering offers a strategy to control carrier transport in low-dimensional materials like transition metal dichalcogenides.

Purpose of the Study:

• To investigate the effect of dielectric screening on hot carrier dynamics in monolayer MoS2.
• To explore how different dielectric substrates influence carrier scattering and recombination.

Main Methods:

• Transient absorption microscopy was employed to study hot carrier dynamics.
• Monolayer MoS2 on various dielectric substrates, including high-κ metal-oxide and quartz, was analyzed.

Main Results:

• High-κ substrates significantly suppressed Coulomb potential, reducing carrier scattering and recombination.
• Hot carrier diffusion length and coefficient were substantially enhanced on high-κ substrates compared to quartz.
• Dielectric engineering effectively modulated hot carrier transport properties.

Conclusions:

• Dielectric engineering is a powerful tool for improving hot carrier transport in MoS2.
• This method enhances efficiency without complex material modifications or external stimuli.
• The findings offer a scalable strategy for advanced electronic and optoelectronic devices.