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

Abstract

Semiconducting single-walled carbon\nnanotubes (s-SWCNTs) are highly\ndesirable for thin-film transistors (TFTs). However, controllable\nand high-yield synthesis of s-SWCNTs remains a challenge. Herein,\nwe develop an aerosol etching strategy to prepare SWCNTs with a high\nsemiconducting ratio. SWCNTs, premade by floating catalyst chemical\nvapor deposition (FCCVD), are selectively etched by carbon dioxide\n(CO₂) in an aerosol phase. Both absorption and Raman spectra\nindicate the decrease of metallic SWCNTs (m-SWCNTs), and electron\ndiffraction further identifies that the s-SWCNT ratio has been increased\nfrom 67.2 to 81.2% by CO₂ etching. This etching is also\nfound to have dominant selectivity on the chiral angle; near-zigzag\nSWCNTs with chirality are more favored to be removed. In addition,\nthin films with high-purity semiconducting SWCNTs could be obtained\nby dry deposition since both the synthesis and etching processes take\nplace in the aerosol phase. Our technique offers a promising option\nfor the high-yield synthesis of s-SWCNTs and implies potential applications\nin TFTs.