Polymer Electrolyte Gated Inorganic Transistors

Electric field-induced charge at the interface between gate dielectric and semiconductor is the basis of current semiconductor technology. We report that it is possible to use polymer electrolyte to gate inorganic materials, and to achieve field-induced `doping' equivalent to a full surface coverage of charged ions per unit cell area. Very high field-induced carrier densities, $\sim $10$^{15}$~cm$^{-2}$, in the transistor channel of La$_{0.8}$Ca$_{0.2}$MnO$_{3}$ devices enable modulation of the Curie temperature of over 30~K. We have also used electrolyte gating of the superconductor YBa$_{2}$Cu$_{3}$O$_{7-x}$ to modulate the onset of superconductivity. This creates an exciting opportunity for use of the electrolyte as gate dielectric in a wide variety of inorganic materials to explore formerly inaccessible band-filling regimes without the need for chemical substitution and additional disorder.