Vertical organic-inorganic hybrid transparent oxide TFTs gated by biodegradable electric-double-layer biopolymer

Vertical organic-inorganic hybrid oxide-based electric-double-layer (EDL) thin-film transistors (TFTs) are successfully demonstrated. Low-cost biodegradable chitosan biopolymer is proposed as an efficient EDL electrolyte dielectric in such vertical transparent TFTs. The device is completely transparent in the range of visible light and the whole fabrication process is completed at room temperature. It exhibits a good performance with a large output current of ∼8 mA/cm2, a large current on/off ratio of ∼105, a small subthreshold swing of 0.33 V/dec, and a low operation voltage of only 2 V, respectively. Moreover, an energy band diagram based on vertical EDL modulation is proposed to understand the device mechanism. Such vertical organic-inorganic hybrid transistor with a vertical channel may be very promising for some important applications in the state-of-the-art low-cost portable transparent flexible electronics.