Flexible IZO Homojunction TFTs With Graphene Oxide/Chitosan Composite Gate Dielectrics on Paper Substrates

Solution-processed graphene oxide/chitosan composite electrolyte film showed a large specific gate electric-double-layer capacitance of
$\sim 3.16~\mu \text{F}$
/cm
$^{{\mathsf {2}}}$
at 1 Hz. Indium–zinc-oxide (IZO) homojunction thin-film transistors (TFTs) on paper substrates using such composite electrolytes as gate dielectrics showed a good electrical performance and a high stability. Flexible IZO-based homojunction TFTs showed a high drain current ON/OFF ratio of
$\sim \textsf {1.8}\times \textsf {10}^{{\textsf {7}}}$
, a large field-effect mobility of >30 cm
$^{{\textsf {2}}}\text{V}^{{-\textsf {1}}}\text{s}^{{-\textsf {1}}}$
, and a low subthreshold swing of 90 mV/decade. At last, a resistor-loaded inverter with a maximal conversion factor of 6.7, and a dual in-plane gate NAND logic operation were also demonstrated on such flexible IZO-based TFTs. Such oxide-based homojunction TFTs on paper substrates have potential applications in next-generation low-cost and portable new-concept electronics.