  We report novel design for thermoelectric device which can control
thermoelectric properties of p-type and n-type materials simultaneously by
electric double-layer gating. Here, p-type Cu2O and n-type ZnO were used as
positive and negative electrodes of the electric double-layer capacitor
structure. When the gate voltage was applied between two electrodes, the holes
and electrons were accumulated on the surface of Cu2O and ZnO, respectively.
The thermopower was measured by applying thermal gradient along the accumulated
layer on the electrodes. We demonstrate here that the accumulated layers are
worked as a p-n pair of the thermoelectric device.
