The field of synaptic transistor research has been gaining attention for analog computing solutions in recent years. This is due to their potential of forming networks to overcome the von Neumann bottleneck, which is the fundamental limitation in traditional digital computing systems caused by the separation of data memory and processing units. Synaptic transistors rely on the ability to form junctions with each other that can be strengthened or weakened by external stimuli causing transport processes such as intercalation of ions. Mimicking the behavior of biological synapses in this way allows for advancements in energy efficiency and processor performance as well as new forms of computing, such as neuromorphic computing and artificial intelligence, inspired by the structure and function of the brain.

Among the different solutions suggested in literature, Electrolyte-Gated Transistors (EGTs) – which are essentially conventional Field-Effect Transistors (FETs) where the gate dielectric is replaced by an electrolyte with mobile ions – have recently been proposed. Many of these EGTs are based on the principle of ionic intercalation, utilizing the active kinetics of ions such as H⁺ or Li⁺. On the other hand, perovskite oxide materials hold large potential as EGTs due to their ability to be easily modified by oxide-ion intercalation, with oxide-ion insertion being more widely applicable than other types of ions. However, the drawback of the several orders of magnitude lower oxide-ion transport present a large drawback, especially in all-solid-state EGTs. The specific EGT studied in this research is a symmetric battery-like device in which oxide-ions are transferred between two mixed ionic-electronic conducting (MIEC) perovskite oxide thin-films (i.e. channel and gate) through a solid state electrolyte.  In order to address the sluggish oxide-ion diffusivity, a superior oxide-ion conducting thin film of Bi₂V_1‑xCu_xO_(11/2)‑x (BICUVOX) with highest oxide-ion conductivities at low temperatures ever reported is used as low temperature electrolyte.^[1] This EGT is manufactured by pulsed laser deposition (PLD), Photolithography and reactive ion milling. The conductance of the channel is controlled via a gate bias, allowing for oxide-ion intercalation between gate and channel as well as multistate operation in the millisecond range. In-situ electrical conductivity measurements at low temperatures (<150 °C) reveal fast and remarkable low energy consumption. Due to its multi-states, the presented EGT reveals synaptic features such as short- and long-term plasticity (STP, LTP), low asymmetric ratio during weight update and broad dynamic range which are known as fundamental properties of synaptic plasticity in biological neural networks. By this, the proposed synaptic transistor has the potential to lead to a breakthrough in energy efficiency and processor performance in information technology.