On the factors affecting the response time of synaptic ion-gated transistors

Abstract

Ion-Gated Transistors (IGTs) feature the processing rate of the human brain for neuromorphic computing. Furthermore, they require low power for training and deployment of neural network algorithms. Neuromorphic computing requires both long-term and short-term potentiation, within the same device. The nature of the doping mechanism in IGTs affects their time-resolved properties, key for their use as neuromorphic devices. Depending on the permeability of the semiconducting channel to ions, IGTs undergo electrochemical (three-dimensional) or electrostatic (field-effect, two-dimensional) doping, which leads to a wide range of IGT response times. Here, we propose a methodology to control the response time of IGTs made up of films of poly(3-hexylthiophene (P3HT) as the semiconducting channel and the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [EMIM][TFSI] as the gating medium. The methodology includes the effect of the pulse frequency of the applied gate-source voltage (V_gs), the number of applied V_gs pulses, and the V_gs pulse duration. It also considers the effect of the values of the applied V_gs and drain-source (V_ds) voltages. Last but not least, the methodology includes the effect of the V_gs sampling time. Our results contribute to the understanding of how to achieve plasticity in IGTs.