Enhanced Electrical Transport in Carbon Nanotube Thin Films through Defect Modulation

Abstract

The electrical properties of single-wall carbon nanotube (SWCNT) thin films were enhanced through defect introduction and subsequent thermal annealing in forming gas. The defect density in the SWCNT thin films was modulated using ion irradiation with 150 keV 11B+ over the fluence range of 1 × 1013 and 1 × 1015 ions/cm2. Following thermal annealing at 1000 °C in forming gas, partial recovery in the optical absorbance and Raman spectra is observed at all fluences studied, with 100% recovery observed in samples exposed to a fluence less than 5 × 1013 ions/cm2. By comparison, annealing yields near complete recovery of the electrical conductivity at all fluences studied (up to 1 × 1015 ions/cm2). Remarkably, radiation exposure up to a fluence of 1 × 1014 ions/cm2 followed by thermal annealing improves the electrical conductivity, exceeding the as-purified value by as much as ∼4×. These results implicate the origin of the enhanced SWCNT network conductance with the formation of transport-enhancing inter-SWCNT bridges that decrease inter-SWCNT junction resistance, thereby enhancing the overall network connectivity.