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

Abstract

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.