Long-memory retention and self-powered ultraviolet artificial synapses realized by multi-cation metal oxide semiconductors

Abstract

Via the low-cost electrospinning technique, we demonstrate artificial synaptic transistors made of multi-cation indium zinc tin oxide (IZTO) nanowires. By adjusting the ratio of indium ions in IZTO, we found that the IZTO-6 based optical synaptic devices exhibited excellent optical response when the ratio is 6 : 1 : 2. Importantly, we have obtained improved long-memory retention for up to approximately three hours. After decaying for approximately three hours, the recorded excitatory postsynaptic current (EPSC) can account for around 50% of the EPSC peak. Furthermore, Al/IZTO-6/Ni optical synaptic devices with asymmetric metal contact structures and large work function differences can simulate biological synapses without V_DS biasing, suggesting the self-powering capability of MOS based synapses for future low energy-consumption building blocks of in-memory computing systems.