Towards the synthesis of semiconducting single-walled carbon nanotubes by floating-catalyst chemical vapor deposition: Challenges of reproducibility

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2022-08-15

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Mcode

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Language

en

Pages

9
92-100

Series

Carbon, Volume 195

Abstract

High-purity semiconducting single-walled carbon nanotubes (s-SWCNTs) are of paramount significance for the fabrication of high-performance electronics. Here, we present continuous production of high-purity, long, and isolated s-SWCNTs by gas-phase synthesis, retaining the pristine morphologies of as-synthesized nanotubes. The s-SWCNTs were synthesized at ca. 920 °C using ethanol and methanol as carbon source and growth enhancer, respectively in N2 and H2. The purity of as-produced s-SWCNTs with a mean length of 15.2 μm can reach 98% as determined by optical absorption spectroscopy. We observed that the overpressure in the reactor and methanol are the principal causes of the enrichment of s-SWCNTs. Specifically, the s-SWCNTs were found to be more negatively charged, and oxygen-contained species play critical roles in the s-SWCNT synthesis. Through the demonstration of field-effect transistors, the s-SWCNTs exhibit a high mean charge carrier mobility of 453.3 cm2 V−1 s−1 which is 2.27 times higher than that of the transistors fabricated with high-quality dispersion-processed SWCNTs. Additionally, we discuss the challenges of synthesis repeatability and recommend a few tips to improve reproducibility. Our study represents an important step towards the scalable production of clean, long, and isolated s-SWCNTs with high purity and narrow bandgap distribution.

Description

Funding Information: This work was supported by the Academy of Finland via projects 286546 (DEMEC), 292600 (SUPER), and 316572 (CNTstress), as well as TEKES in Finland via projects 3303/31/2015 (CNT-PV) and 1882/31/2016 (FEDOC). P. Liu acknowledges the financial support from China Scholarship Council (No. 202006310007 ). This work made use of the Aalto University Nanomicroscopy Center (Aalto-NMC) premises. Aalto NanoFab (Micronova) cleanroom resources are greatly appreciated. The authors sincerely thank Dr. Mirkka Jones for proof reading.

Keywords

Gas-phase synthesis, Methanol, Pressure, Reproducibility, Semiconducting single-walled carbon nanotubes

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Citation

Ding, E X, Liu, P, Khan, A T, Zhang, Q, Wei, N, Jiang, H & Kauppinen, E I 2022, ' Towards the synthesis of semiconducting single-walled carbon nanotubes by floating-catalyst chemical vapor deposition : Challenges of reproducibility ', Carbon, vol. 195, pp. 92-100 . https://doi.org/10.1016/j.carbon.2022.04.020