Single-Walled Carbon Nanotube Thin Film with High Semiconducting Purity by Aerosol Etching toward Thin-Film Transistors

Semiconducting single-walled carbon nanotubes (s-SWCNTs) are highly desirable for thin-film transistors (TFTs). However, controllable and high-yield synthesis of s-SWCNTs remains a challenge. Herein, we develop an aerosol etching strategy to prepare SWCNTs with a high semiconducting ratio. SWCNTs, premade by floating catalyst chemical vapor deposition (FCCVD), are selectively etched by carbon dioxide (CO2) in an aerosol phase. Both absorption and Raman spectra indicate the decrease of metallic SWCNTs (m-SWCNTs), and electron diffraction further identifies that the s-SWCNT ratio has been increased from 67.2 to 81.2% by CO2 etching. This etching is also found to have dominant selectivity on the chiral angle; near-zigzag SWCNTs with chirality are more favored to be removed. In addition, thin films with high-purity semiconducting SWCNTs could be obtained by dry deposition since both the synthesis and etching processes take place in the aerosol phase. Our technique offers a promising option for the high-yield synthesis of s-SWCNTs and implies potential applications in TFTs.