Ferroelectric-Driven Asymmetric Band Engineering for Self-Powered Visible–SWIR Reconfigurable Photodetection

Le résumé fourni par la source

The integration of ferroelectric materials with 2-D semiconductors offers a powerful route toward adaptive, low-power, and multifunctional optoelectronics. Here, we report a ferroelectric-gated broadband photodetector based on a WSe2lateral homojunction integrated on a PMN–PT substrate. Asymmetric graphene contacts expose only part of the WSe2channel to the ferroelectric polarization field, creating localized electrostatic potential gradients that enable ferroelectric-controlled formation of homo-PN and NP junctions. Consequently, the device exhibits nonvolatile rectification ($\gt\!10^{{3}}$) and a polarization-switchable, self-powered photoresponse under visible illumination (532 nm), enabling near-zero static power operation. Under 1550 nm illumination, a unipolar pyroelectric photocurrent arising from PMN–PT provides short-wave infrared (SWIR) detection, extending the spectral range. Scanning photocurrent mapping directly reveals a polarity reversal of the WSe2homojunction under opposite ferroelectric polarization states, confirming localized channel modulation by the substrate. Raman spectroscopy shows that only the nonshielded WSe2region experiences ferroelectric-induced phonon shifts, corroborating the asymmetric field-modulation mechanism. Driven by these dual physical mechanisms, we propose an event-driven readout scheme that delivers visible-band event imaging and SWIR fusion imaging on a single platform, facilitating robust perception in high-dynamic-range scenes such as tunnel exits. This work establishes a multifunctional route for integrating ferroelectric gating with 2-D semiconductors toward reconfigurable, broadband, and low-power vision systems.

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