Positive-Negative Photoelectric Effect Induced by the Asymmetric Schottky Interface and Its Application in Polarization-Sensitive Infrared Wavelength-Recognizing Artificial Visual Synapses.

This work proposes a design of asymmetric Schottky junctions and constructs a two-dimensional heterojunction using anisotropic semiconductor ReS2 and semimetals graphene (Gr) and PtSe2. Under the dual mechanism of the photovoltaic effect and the photothermal effect, the heterojunction achieves self-powered photodetection under 405-1064 nm light illumination, realizes nearly symmetric current synaptic pulse modulation via asymmetric positive-negative voltage regulation, and exhibits positive-negative photoelectric response switching, with the polarity of the photocurrent dynamically adjustable based on the voltage and light wavelength. Within the 1064-2200 nm broad infrared spectrum, the heterojunction stably implements core synaptic functions such as pair-pulse facilitation (PPF) and depression (PPD) at a low voltage of -70 mV, with a single-pulse energy consumption as low as 0.35 pJ. Notably, it possesses excellent polarization sensitivity (achieving a polarization ratio of 6.6 under 1064 nm light illumination), successfully integrating polarization sensitivity and infrared wavelength recognition functionalities.