Flexible Dual-Gate Oxide TFTs Gated by Chitosan Film on Paper Substrates

Low-voltage flexible dual-gate indium-tin-oxide-based thin-film transistors (TFTs) are self-assembled on SiO
₂
-covered paper substrates by one shadow mask diffraction method. Solution-processed chitosan gate dielectric films have a large gate specific capacitance (5.8 μF/cm
²
) due to the electric-double-layer effect. The subthreshold swing, drain-current on/off ratio, and field-effect mobility are estimated to be 80 mV/dec, 4 ×10
⁶
, and 9.3 cm
²
/V·s, respectively. Low-voltage operation mechanism and threshold voltage modulation of such dual-gate paper TFTs are investigated.