Carbon nanotube thin film transistors based on aerosol methods

We demonstrate a fabrication method for high-performance field-effect transistors (FETs) based on dry-processed random single-walled carbon nanotube networks (CNTNs) deposited at room temperature. This method is an advantageous alternative to solution-processed and direct CVD grown CNTN FETs, which allows using various substrate materials, including heat-intolerant plastic substrates, and enables an efficient, density-controlled, scalable deposition of as-produced single-walled CNTNs on the substrate directly from the aerosol (floating catalyst) synthesis reactor. Two types of thin film transistor (TFT) structures were fabricated to evaluate the FET performance of dry-processed CNTNs: bottom-gate transistors on Si/SiO₂ substrates and top-gate transistors on polymer substrates. Devices exhibited on/off ratios up to 10⁵ and field-effect mobilities up to 4 cm² V⁻¹ s⁻¹. The suppression of hysteresis in the bottom-gate device transfer characteristics by means of thermal treatment in vacuum and passivation by an atomic layer deposited Al₂O₃ film was investigated. A 32 nm thick Al₂O₃ layer was found to be able to eliminate the hysteresis.