Electrostatic modification of oxide semiconductors by electric double layers of microporous SiO2-based solid electrolyte

We have studied electrostatic modulation of InGaZnO4 and indium-tin oxide (ITO) channel by using microporous SiO2-based solid electrolyte as gate dielectrics in the field-effect transistors (FETs) structure. H3PO4-treated SiO2-based solid electrolyte was found to be have a large capacitance (9.5 mu F/cm(2)) due to the strong capacitive coupling by electric double layer(EDL) between H3PO4-treated solid electrolyte and active channel. High carrier densities (>10(14)/cm(2)) and large metallic conductivities (2180 S/cm) in InGaZnO4 channel were electrostatically induced, while a metal-to-insulator transition (more than 6 orders of magnitude of channel resistance modulation) was observed in ITO channel by using such FET structure. Furthermore, device simulation based on an EDL model can also reproduce the transfer characteristics well. Our result provides a new opportunity for electrostatic modulation of the electronic properties in condensed matter. (C) 2011 American Institute of Physics. [doi:10.1063/1.3553869]