Improving Performance of All-Carbon-Nanotube Thin-Film Transistors by Low Temperature Supercritical CO2 Fluid Activation

In this letter, we propose a novel activation treatment using supercritical CO2 fluid (SCCO2) to improve the comprehensive performance of all-carbon-nanotube thin-film transistors (TFTs) at low temperature. After the treatment, the subthreshold swing, the threshold voltage, and the leakage current of the devices are decreased. Meanwhile, the mobility and on/off current ratio of the device are improved significantly. We verify the passivation mechanism of the SCCO2 treatment by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis. The result shows that the SCCO2 treatment improves the oxidation level, passivates the defects in the dielectric layer, and removes the impurity molecules adsorbed by carbon nanotubes. The SCCO2 treatment performs component modification for the device by its excellent penetrating and dissolving capabilities without causing the structural damage. It has a great potential to be generally applied to activate TFTs with processing temperature limitation.