A voltage-controlled double layer

In an MOS device, the application of a bias field across the oxide layer controls the concentration of electrons or holes in the channel and leads to enhanced conduction between the source and the drain. The concentration of ionic species in a double layer can be controlled in a similar way by applying a bias field across a dielectric layer in contact with bipolar medium. As an example, the effect of a bias field on the frequency response of an interdigital electrode structure in Exxon Univolt 60 transformer oil at room temperature was investigated experimentally. The frequency dependence of the gain and phase associated with the potentials at the driven and sensing electrodes are plotted for several values of the bias voltage