近期，本课题组张敏老师和张紫薇同学分别以通讯作者和第一作者在EDL上发表了题为“Improving Performance of All-Carbon-Nanotube Thin-Film Transistors by Low Temperature Supercritical CO2 Fluid Activation”的研究成果。
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. 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.
In conclusion, the comprehensive electrical performance of the ACNT-TFTs is improved by the SCCO2 treatment. The subthreshold swing and the threshold voltage of the device are decreased from 81.85 mV/dec to 66.01 mV/dec, and 1.18V to 0.56V, respectively. The mobility of the typical transistor is increased by 1.22 times. By the SCCO2 treatment, the dielectric layer has been modified effectively as the stoichiometric ratio of the Si-O bonds increased. The defects in the interface between channel and dielectric layer have been reduced sufficiently by the treatment. Besides, the impurities absorbed by CNTs have been removed. This work demonstrates that the SCCO2 treatment can enhance the electrical performance efficiently even after the devices have been completed. It provides a promising solution to enhance the device performance in a non-destructive way for the new generation electronic devices like flexible and stretchable devices, which are usually processed under low temperature.