Junction Field-Effect Transistors Based on MoSe₂/WSe₂ Heterostructures for High-Performance Photodetection

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer potential for high-performance, ultracompact photodetectors.
• Current 2D photodetectors face challenges in balancing photodetectivity and photoresponsivity due to dark currents or lack of gain.
• Photodetector performance is limited by dark current and gain mechanisms.

Purpose of the Study:

• To design and demonstrate a gate-tunable junction field-effect transistor photodetector based on MoSe2 and WSe2.
• To overcome the limitations of existing 2D photodetectors by effectively reducing dark current.
• To achieve a balance between high photodetectivity and photoresponsivity.

Main Methods:

• Fabrication of a photodetector device utilizing a heterojunction of Molybdenum Diselenide (MoSe2) and Tungsten Diselenide (WSe2).
• Application of source-drain and gate bias to modulate the depletion layer and Schottky barrier.
• Characterization of device performance under laser irradiation at various wavelengths.

Main Results:

• Achieved ultrahigh photodetectivity of 1.55 × 10^13 Jones and an optical switching ratio of 10^4.
• Demonstrated high photoresponsivity of 476 A/W and an ultrafast response time of 50 μs.
• Extended detection capability to the 1550 nm band, showcasing broad spectral applicability.

Conclusions:

• The developed gate-tunable 2D heterojunction photodetector effectively reduces dark current, enhancing performance.
• The device exhibits excellent photodetectivity, photoresponsivity, and response speed, surpassing previous limitations.
• This work highlights the significant potential of 2D heterojunctions for next-generation photonic sensor applications.