Proton Conductor Gated Synaptic Transistor Based on Transparent IGZO for Realizing Electrical and UV Light Stimulus

Abstract

Synaptic transistors mimicking the biological synapse’s short term plasticity and short-term memory property were demonstrated using the amorphous indium–gallium–zinc oxide channel in combination with the nanogranular SiO2 as the gate oxide. The lowest energy consumption was 1.08 pJ per pulse activity and the operating voltage was within 100 mV. The device’s plasticity and memory characteristics can be explained by the movement of protons in the insulating layer. The proton relaxation was revealed by two ways of dual sweeping: continuous and discontinuous sweepings. We observed that the excitatory postsynaptic current (EPSC) rose as the voltage decreased anomaly during the backward sweeping process. In the electrical stimulus, both the short-term potentiation and depression were observed for this proposed device. The amplitude of the EPSC changed with the pulse number following a saturating exponential function. For the electrical stimulus under constant illumination, the UV light wavelength, intensity and duration time were found to have little effect on the paired pulse facilitation. While in the light stimulus, the light frequency promoted the paired pulse facilitation and had more effect on the synapse’s plasticity than the other light pulse parameters including intensity, numbers and width.