A synaptic memristor based on natural organic honey with neural facilitation

Neural facilitation is an essential activity-dependent synaptic plasticity in most chemically transmitting synapses. Emerging artificial synaptic devices need to be capable of emulating this function in order to be used in brain-inspired neuromorphic computing systems. In this paper, neural facilitation in natural organic honey based synaptic memristor was investigated. The memristive layer was fabricated by commercially purchased honey via a solution-based process and sandwiched in between Al top electrode and ITO bottom electrode. Two process conditions, 90 °C/8 h and 140 °C/2 h were applied to dry the honey thin film for comparison. Test results show that both devices demonstrated bipolar resistive switching and neural facilitation behaviors, while the memristor with the honey film dried by 90 °C/8 h demonstrated a larger on/off ratio and read memory window, lower current at high-resistant state, and larger facilitation index. The index is also larger than our previously reported honey-memristor with same drying conditions but Ag top electrode, and memristors based on other natural organic materials such as chicken albumen and lignin. The index decayed following two exponential phases as a function of the interval time of the two stimulation voltage pulses, which is similar to biological synapses. Besides shorter pulse interval time, the response of facilitation also enhanced by larger magnitude and width of the stimulation voltage pulses.