Air-Stable Conversion of Separated Carbon Nanotube Thin-Film Transistors from p-Type to n-Type Using Atomic Layer Deposition of High-κ Oxide and Its Application in

Duetoextraordinaryelectricalproperties,preseparated,highpuritysemiconducting carbon nanotubes hold great potential for thin-film transistors (TFTs) and integrated circuit applications. One of the main challenges it stillfaces is the fabrication of air-stable n-type nanotube TFTs with industry-compatible techniques. Here in this paper, we report a novel and highly reliable method of converting the as-made p-type TFTs using preseparated semiconducting nanotubes into air-stablen-typetransistorsbyaddingahigh-κoxidepassivationlayerusingatomiclayerdeposition (ALD).Then-typedevicesexhibitsymmetricelectricalperformancecomparedwiththep-typedevices in terms of on-current, on/off ratio, and device mobility. Various factors affecting the conversion process, including ALD temperature, metal contact material, and channel length, have also been systematically studied by a series of designed experiments. A complementary metal-oxide- semiconductor (CMOS) inverter with rail-to-rail output, symmetric input/output behavior, and large noise margin has been further demonstrated. The excellent performance gives us the feasibility of cascading multiple stages of logic blocks and larger scale integration. Our approach can serve as the critical foundation for future nanotube-based thin-film macroelectronics.