Broadband Van-der-Waals Photodetector Driven by Ferroelectric Polarization.

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Physics

Background:

• Broadband photodetectors are crucial for industrial applications beyond visible light.
• 2D van der Waals (vdW) semiconductors offer strong light-matter interaction but often have large bandgaps, limiting infrared detection.
• Ternary alloys are currently used but have performance limitations.

Purpose of the Study:

• To develop a high-performance broadband photodetector utilizing a 2D vdW heterojunction.
• To explore the potential of ReS₂/WSe₂ heterostructures for near-infrared (NIR) detection.
• To investigate the effect of ferroelectric gating on photodetector performance.

Main Methods:

• Fabrication of a ReS₂/WSe₂ vdW heterojunction-channel photodetector.
• Utilized staggered type-II bandgap alignment for interlayer charge transfer.
• Employed ferroelectric gating with poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) to tune device characteristics.

Main Results:

• Achieved broadband light detection from >1300 nm up to 2700 nm.
• Demonstrated a high photoresponsivity of up to 6.9 × 10³ A W⁻¹.
• Obtained a low dark current below 0.26 nA with ferroelectric gating control.

Conclusions:

• The ReS₂/WSe₂ vdW heterojunction photodetector offers excellent NIR detection capabilities.
• Ferroelectric gating effectively enhances photoresponsivity and reduces dark current.
• This technology presents a promising alternative to traditional ternary alloy photodetectors for next-generation optoelectronics.