Reconfigurable Optoelectronic Functionality Implemented in Ta2NiSe5/WS2 Heterostructure toward Multifunctional Applications

Abstract

With the advancement of artificial intelligence, an increasing array of application scenarios is imposing diverse demands on optoelectronic devices. Consequently, the pursuit of multi-functional optoelectronic devices has become highly desirable to streamline system design and minimize costs. However, the fabrication of optoelectronic devices that concurrently facilitate both photodetection and neuromorphic visual simulation poses a significant challenge due to conflicting structural requirements. Herein, we present a Ta2NiSe5/WS2 heterostructure that exhibits dual-modal functionality, integrating photodetection and neuromorphic visual simulation within a single device. Specifically, the device operates in a photovoltaic mode under self-powered and reverse bias conditions, transitioning to a photoconductive mode under forward bias. In the photovoltaic mode, it demonstrates a high responsivity of 6.58 A/W, exceptional detectivity of 1.56×1012 Jones, and rapid rise/fall times of 46.9/48.9 µs, enabling effective photodetection. Furthermore, in the photoconductive mode, the device achieves basic synaptic functions for neuromorphic visual sensing, including short-term plasticity (STP), long-term plasticity (LTP), and the ability to "learn-forget-relearn" through photocarrier trapping/de-trapping processes, with a paired pulse facilitation (PPF) of 31.34%. This research introduces a novel strategy for the development of future multifunctional, integrated, intelligent, and compact optoelectronic devices.