Ultrasensitive and spectrally selective WSe₂/MoS₂ photodetector via metal–2D interface modulation for infrared signal recognition

Abstract

van der Waals (vdW) metal–semiconductor interfaces offer new pathways for overcoming Fermi level pinning (FLP) in 2D electronic and optoelectronic devices. Herein, we demonstrate an ultrasensitive and spectrally selective photodetector based on a WSe₂/MoS₂ heterojunction, in which a vdW metal contact significantly suppresses FLP by minimizing mid-gap states at the contact interface. This dramatically enhances carrier injection and transport efficiency. The photodetector exhibits narrowband wavelength discrimination as fine as 5 nm, even in the IR region, with an accuracy of over 99% in heart rate detection compared with commercial photoplethysmography systems. Our strategy establishes a universal framework for precision optical sensing and infrared signal recognition, paving the way for high-performance intelligent optoelectronic systems.

Keywords

Fermi level pinning / photoplethysmography sensor / van der Waals contact / WSe₂/MoS₂ heterojunction photodetector

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