Double Gate PbS Quantum Dot Field‐Effect Transistors for Tuneable Electrical Characteristics

In this work colloidal quantum dots double gate transistors are introduced. A high‐ k ( k = 43) relaxor ferroelectric polymer is used as a dielectric material for the top gate in a device where the other gate is fabricated from SiO 2 . The device in double gate configuration is characterized by reduced hysteresis in the transfer curves measured by separately sweeping the voltage of the SiO 2 and of the polymer gate. Gating with the relaxor polymer leads to mobility values of μ e = 1.1 cm 2 V −1 s −1 and μ h = 6 × 10 −3 cm 2 V −1 s −1 that exceed those extracted from the SiO 2 gating: μ e = 0.5 cm 2 V −1 s −1 and μ h = 2 × 10 −3 cm 2 V −1 s −1 . Measurements under double gating conditions prove that the device works in a single channel mode that is delocalized over the whole film thickness. Double gating allows for shifting the threshold voltage into a desired position and also allows increasing the on‐current of the devices.