2D Vertical Heterojunction with Codirectional Built-in Electric Fields and Plasmonic Hot-Electron Effect for...

Area of Science:

• Materials Science
• Nanotechnology
• Device Physics

Background:

• Two-dimensional (2D) vertical heterojunctions offer potential for integrating self-powered photodetectors (sense) and neuromorphic synapses (think).
• Existing designs face challenges from interface-induced opposing electric fields and limited spectral response.
• Efficient vertical charge transport is crucial for these integrated functionalities.

Purpose of the Study:

• To address limitations in 2D vertical heterojunctions for integrated sense-think devices.
• To enhance spectral response and improve carrier separation and transport.
• To develop a novel architecture for self-powered broadband photodetection and low-power neuromorphic computing.

Main Methods:

• Fabrication of a graphene (Gr)/WSe2/Ag vertical heterojunction.
• Utilizing minimized carrier transport distance and codirectional built-in electric fields.
• Incorporating plasmonic hot-electron effect to extend spectral response.

Main Results:

• A 10.69-fold increase in photocurrent density under 405 nm light due to vertical structure and codirectional fields.
• A 35-fold increase in photocurrent density under 1064 nm light via plasmonic hot electrons, enabling 1550 nm detection.
• Ultralow-power synaptic behavior with energy consumption from 0.42 to 320 pJ across visible to near-infrared wavelengths.

Conclusions:

• The developed heterojunction demonstrates excellent self-powered broadband photodetection.
• The device exhibits efficient low-power visual synaptic functions.
• This architecture shows significant potential for advanced "sense-think" intelligent devices.