Tunneling Diode Based on WSe₂ /SnS₂ Heterostructure Incorporating High Detectivity and Responsivity

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Atomically thin 2D materials enable advanced van der Waals (vdW) heterostructures for optoelectronics.
• Photodetectors based on vdW heterostructures face a trade-off between photodetectivity and photoresponsivity.

Purpose of the Study:

• To engineer a highly sensitive WSe2/SnS2 vdW heterostructure photodiode.
• To overcome the limitations of conventional photodetectors by achieving high performance in both photodetectivity and photoresponsivity.

Main Methods:

• Fabrication of a WSe2/SnS2 vdW heterostructure on a BN thin film via exfoliation and manual stacking.
• Characterization of energy band structures and electrical properties to understand device physics.
• Analysis of dark currents and photocurrent under illumination.

Main Results:

• The WSe2/SnS2 vdW heterostructure exhibited ultralow dark currents due to a depletion region.
• High direct tunneling current was observed under illumination, confirmed by energy band analysis.
• Achieved ultrahigh photodetectivity (1.29 × 10^13 Jones) and photoresponsivity (244 A W^-1) at 550 nm illumination.

Conclusions:

• The developed WSe2/SnS2 vdW heterostructure demonstrates superior performance in photodetectors.
• This work offers a promising pathway for next-generation optoelectronic devices with enhanced sensitivity.