Patterned Membrane as Substrate and Electrolyte in Depletion- and Enhancement Mode Ion-Modulated Transistors

In this paper, we have utilized a poly(vinylidene difluoride) poly(styrene) sulfonic acid patterned ion-conducting membrane as a platform onto which electronics based on both depletion mode and enhancement mode ion-modulated transistors have been built. The flexible membrane itself acts as both the substrate for, and the electrolyte in, the two transistor types. This is possible since the membrane is modified so that it is ion-conducting in certain places and insulating in others. The two transistor types have different semiconductors, one being conducting (the depletion mode transistor) and the other nonconducting (the enhancement mode transistor) in the normal and un-biased state. Both transistor types are potentially-driven with the crucial difference that the depletion mode transistor channel is electrochemically operated. The two transistor types are fabricated simultaneously on the same substrate, but more complicated structures such as inverters and ring-oscillators, operating at low voltages, are presented in this paper to demonstrate the usefulness of the membrane as a platform for cheap and disposable electronics.