Self-Powered Photodetector with High Efficiency and Polarization Sensitivity Enabled by WSe

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Self-powered photodetectors are crucial for low-power Internet of Things (IoT) applications.
• Achieving miniaturization, high quantum efficiency, and multifunctionality simultaneously remains a significant challenge.

Purpose of the Study:

• To develop a high-efficiency, polarization-sensitive photodetector with enhanced performance.
• To explore the potential of two-dimensional (2D) WSe2/Ta2NiSe5/WSe2 van der Waals (vdW) dual heterojunctions (DHJ) for photodetector applications.

Main Methods:

• Fabrication of a sandwich-like electrode pair with 2D WSe2/Ta2NiSe5/WSe2 vdW DHJ.
• Characterization of the device's spectral response, external quantum efficiency (EQE), power conversion efficiency (PCE), and response speed.
• Evaluation of polarization sensitivity utilizing the in-plane anisotropy of Ta2NiSe5.

Main Results:

• The DHJ device exhibits a broadband spectral response (400-1550 nm).
• Outstanding performance under 635 nm light: ultrahigh EQE (85.5%), pronounced PCE (1.9%), and fast response (420/640 μs).
• Competitive polarization sensitivities (13.9 and 14.8 at 635 and 808 nm, respectively) and demonstrated self-powered visible imaging capability.

Conclusions:

• The developed DHJ photodetector surpasses single heterojunction performance.
• This work presents a promising platform for high-performance, multifunctional self-powered photodetectors.
• The findings advance the development of advanced optoelectronic devices for IoT and imaging.