High-performance field-effect transistors with semiconducting-rich single-walled carbon nanotube bundle

Single-walled carbon nanotubes (SWCNTs), typically produced as bundles in floating catalyst chemical vapor deposition (FC-CVD), exhibit exceptional electronic properties, making them highly promising for high-performance electronics. This work examines the transport characteristics and electrical performance of field-effect transistors (FETs) fabricated from two high crystalline SWCNT bundle types: Small Bundle Small Diameter (SBSD) and Large Bundle Large Diameter (LBLD). SBSD and LBLD SWCNT bundles, synthesized via FC-CVD, had mean bundle diameters of 4.1 nm and 7.1 nm, and mean tube diameters of 1.4 nm and 1.9 nm, respectively. Despite electron diffraction revealing metallic fractions of 38 % for SBSD and 46.3 % for LBLD, interestingly a higher-than-expected fraction of FETs with 71.5 % for SBSD and 62 % for LBLD, demonstrated semiconducting behavior. Single SBSD SWCNT FETs achieved a mean charge carrier mobility of 2817 cm²V^–1_S⁻¹, while single LBLD SWCNT FETs reached a mean value of 5378 cm²V^–1_S⁻¹, among the highest reported. The mean mobility in single junction FETs decreased about fourfold to 737 cm²V⁻¹s⁻¹ for SBSD and threefold to 1732 cm²V⁻¹s⁻¹ for LBLD, compared to the single bundle FET. Both SBSD and LBLD SWCNT FETs achieved on-off ratios up to 10⁸, highlighting their potential for advanced electronic applications.