Electrolyte-Gated Transistors for Fundamental Physics and for Applications

Electrolyte-gated transistors (EGTs) constitute a general class of devices in which an electrolyte is employed as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation, high gate-induced carrier densities, and consequently high transconductance. These devices are divided into two broad categories, either the electric double layer transistor (EDLT) or the electrochemical transistor (ECT), depending on the mechanism of operation. This talk will begin with a general description of EGTs using a solid state electrolyte or ion gel, including typical fabrication methods, principles of operation (i.e., electrochemical vs double-layer charging), and quasi-static and dynamic performance. Applications of EGTs in printed electronics and biosensing will be briefly described, and then the discussion will move to use of EGTs to explore transport physics in novel materials at high carrier density. Specific examples include double layer gating of organic semiconductor single crystals such as rubrene and C60, and 2D materials, such as tellurene. In the case of tellurene, we are able to access the insulator-to-metal transition.