Ion-gel gated field-effect transistors with solution-processed oxide semiconductors for bioinspired artificial synapses

With the development of sciences and technologies of artificial intelligence in recent years, more and more attention is focused on the research of the synaptic devices inspired by human brain. In this paper, ion-gel coupled synaptic transistors with solution-possessed amorphous indium-zinc-oxide (In-Zn-O) thin films were demonstrated. Ion-gel dielectric provides a strong ionic/electronic coupling on the solution-processed In-Zn-O thin films, which is due to the very large electric-double-layer (EDL) capacitances (similar to 4.87 mu F/cm(2)). The surface morphology, chemical composition/stoichiometry and electrical performances of In-Zn-O field-effect transistors (FETs) were analyzed as a function of annealing temperature. Most importantly, the ion-gel gated In-Zn-O FETs were used for synaptic functions simulations. The in-plane gate is used as the presynaptic input terminal and the In-Zn-O channel with source/drain electrodes is used as the postsynaptic output terminal. Mobile ions in ion-gel are regarded as neuro-transmitters. Gate pluses were applied on the in-plane electrodes which is analogous to presynaptic spikes onto presynaptic membrane. Fundamental synaptic functions including excitatory postsynaptic current (EPSC), spike time-dependent EPSC, paired-pulse facilitation (PPF), and dynamic synaptic behaviors are mimicked. These results may provide a new opportunity and strategy to develop of highly functional electronic synapses and next-generation neuromorphic systems by using ion-gel gated devices with solution-processed amorphous oxide semiconductors. (C) 2016 Elsevier B.V. All rights reserved.