Progress toward a solid-state ionic field effect transistor

Abstract

This paper reports on the development and characterization of a solid-state ionic field effect transistor (IFET), a device integrating the principles of metal-oxide-semiconductor field effect transistors, electric double layer modeling, and solid-state ionic transport as a platform to investigate and manipulate nanoionic effects. The described solid-state IFET utilizes a sinusoidal external electric field to induce a time-modulated ionic space charge layer conduction channel in an ion-conducting material, such as Nafion, the chosen proton-conducting polymer in this study. The application of double layer modeling to this system establishes a theoretical foundation for device performance, including predicted values for the modulation of the membrane resistance in response to a gating bias. Experimental studies of device prototypes constructed from 25-175-μm-thick Nafion membranes demonstrate indications of ionic space charge layer manipulation for gating voltages of 0.5–10 V in amplitude. Strategies to improve device performance by reducing current leakage and increasing reproducibility include reduction of the gate electrode area and the membrane thickness. Our results show important progress in the development of solid-state IFETs and, as such, demonstrate a promising outlook for improved understanding of nanoionic phenomena.