Water-assisted self-sustained burning of metallic single-walled carbon nanotubes for scalable transistor fabrication

Although aligned arrays of semiconducting single-walled carbon nanotubes（s-SWNTs） are promising for use in next-generation electronics owing to theirultrathin bodies and ideal electrical properties, even a small portion of metallic（m-） counterparts causes excessive leakage in field-effect transistors （FETs）.To fully exploit the benefits of s-SWNTs for use in large-scale systems, it isnecessary to completely eliminate m-SWNTs from as-grown SWNT arrays andthereby obtain purely semiconducting large-area arrays, wherein numerousFETs can be flexibly built. In this study, we performed electrical burning ofm-SWNTs assisted by water vapor and polymer coating to eliminate m-SWNTsover a long length for the scalable fabrication of transistors from the remainings-SWNT arrays. During the electrical-breakdown process, the combination ofwater vapor and the polymer coating significantly enhanced the burning ofthe SWNTs, resulting in a self-sustained reaction along the nanotube axis. Wefound that m-SWNT segments partially remaining on the anode side resultedfrom one-way burning from the initial breakdown position, where Joule-heating-induced oxidation first occurred. The s-SWNT-enriched arrays obtained wereused to fabricate multiple FETs with a high on-off current ratio. The resultsindicate the advantages of this approach over conventional electrical breakdownfor the large-scale purification of s-SWNTs.