Effect of Single-Wall Carbon Nanotube Doping on Solution-Processed Indium Oxide Thin-Film Transistors

The p-type conductivity often observed in single-wall carbon nanotube (SW-CNT) thin-film transistors (TFTs) is usually attributed to the doping effect of oxygen adsorption when SW-CNT are exposed to air caused by differences in the figure of merit, which results in asymmetric electron and hole injection. We performed comparative tests by doping SW-CNTs into the Indium oxide (In2O3/SW-CNT) channel layer, fabricated semiconductor devices, and investigated the device performance and film properties. It was determined that both In2O3 and In2O3/SW-CNT devices exhibit n-type behavior with significant saturation behavior and gate control under positive bias. The In2O3/SW-CNT TFTs have higher saturation mobility (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {sat}}$ </tex-math></inline-formula>) and on/off current ratio (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {ON}}/{I}_{\text {OFF}}$ </tex-math></inline-formula>). In particular, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu _{\text {sat}}$ </tex-math></inline-formula> is increased by ~3 times, and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {ON}}/{I}_{\text {OFF}}$ </tex-math></inline-formula> is increased to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{{6}}$ </tex-math></inline-formula>. Also, under negative bias stress (NBS), it exhibits better stability and signal inversion capability by resistive loading of the inverter. These results indicate that solution-prepared In2O3/SW-CNT TFTs can be used in low-cost, low-temperature, high-performance electronic devices.