Heterostructured Plasmonic Memristors with Tunable Opto-Synaptic Functionalities

Visible light opto-electronic systems with synaptic characteristics have outstanding potential for a wide range of applications from photonic computing to the emulation of the basic functionalities of human visual systems. However, the complexities of photonic memristors and opto-synaptic devices are far beyond the concept of conventional image sensor technology. The development of artificial smart recognition systems requires an integrated complex network of image sensors and memory and processing units, which unfavorably consume a higher amount of electrical energy compared to their natural rival, i.e. the human visionary system. Here, we developed a single-unit photonic memristor for efficient visible light reception with non-volatile opto-resistive switching characteristics. The heterointerface engineering at the plasmonic unit based on heterostructured oxide films enabled the development of a visible-light tunable opto-synaptic device. The N2 incorporation into an atomically-thin In2O3 film at Au/In2O3–TiO2 heterointerfaces ensured the considerable decrease of opto-resistive switching current and enabled synergistic improvement of the long-term plasticity (LTP) of optical synapses. The relaxation time of opto-synapses was controlled by altering the polarization of the Au/In2O3 electrode, ensuring the synergistic improvement of LTP by the increase of photoconductance of the opto-synaptic device. The proof-of-concept of LTP for visible light plasmonic synapses can significantly simplify the circuitry of future artificial visionary systems and contribute to the outstanding development of neuro-optoelectronic technology.