Water electrolysis switches an oxide insulator to a thermoelectric metal

[Nature Communications 2010 (OPEN)


Water is composed of the electrochemically active species, H+ and OH, but has not been used as an active electronic material. In this study, a field-effect transistor is developed that uses water-infiltrated nanoporous glass as the gate insulator; this new application of water may be useful in electronics and energy storage. We fabricated a field-effect transistor structure on an oxide semiconductor, SrTiO3, using water-infiltrated nanoporous glass amorphous 12CaO-7Al2O3 as the gate insulator. Positive gate voltage, electron accumulation, water electrolysis and electrochemical reduction occur successively on the SrTiO3 surface at room temperature. This leads to the formation of a thin (~3 nm) metal layer with an extremely high electron concentration (1015-1016/cm2), which exhibits exotic thermoelectric behaviour.