PMMA/Al ₂ O ₃ bilayer passivation for suppression of hysteresis in chemically doped carbon nanotube thin-film transistors

Hysteresis is usually present in carbon nanotube thin-film transistors exposed to air due to adsorbed water and oxygen molecules. Thus, it is desirable to passivate the device from these environmental effects and provide an air-stable platform for chemical doping to tune the threshold voltages. Here, we demonstrate p- and n-doped carbon nanotube transistors with suppressed hysteresis using bilayer stacking of poly(methyl methacrylate) and aluminum oxide (Al 2 O 3 ) passivation layers using a low-temperature process suitable for flexible substrates. The results show that the bilayer passivation layers achieved reduced hysteresis to be 2.25% of applied gate voltage at low operation voltage as 2 V.