Electric Double-Layer Effect in Solid State Ionics-Based Transistors and the Application to Neuromorphic Computing

Solid state ionics-based field effect transistors with various solid electrolytes and hydrogen-terminated diamond semiconducting channel were utilized for quantitative evaluation of electric double-layer (EDL) charges. The electronic holes induced on the diamond surface due to the EDL effect were dense at the interface of lithium solid electrolytes such as Li-Si-Zr-O, Li3PO4 and LiNbO3 at around 1013/cm2, but very low at the interface with La-Li-Ti-O, indicating that the EDL effect depends on the electrolyte properties. The control of the EDL effect by inserting an interlayer at the lithium solid electrolyte/diamond interface is also performed. The EDL charge–discharge rate differed by more than two orders of magnitude between LiNbO3 and Li3PO4 interfaces. Furthermore, transient response of EDL transistors were applied to the state-of-the-art neuromorphic computing and found to be useful to perform highly precise time-series data prediction tasks.