All-polymer FET based on simple photolithographic micro-patterning of electrically conducting polymer

We fabricated All-polymer FET (field effect transistor) whose substrate., insulating layer, active layer, and electrodes were composed of the organic polymeric materials. Active layer and all electrodes were made by the simple photolithographic micro-patterning of the electrically conducting poly(3,4-ethylenedioxythiophene). We figured out source-drain current (I _SD) of the FET decreased with increase of the positive gate voltage (V_G), implying the p-type FET worked in the depletion mode. Turn-off gate voltage, trans-conductance and on/off ratio were measured to be +30 V, -1. 2 μA/V, and 10⁴, respectively. We believe the All-polymer FET has significant advantages over other existing organic FETs since the device can be fabricated by the simple process at room temperature.