title: Selective Growth of Subnanometer Diameter Single-Walled Carbon Nanotube Arrays in Hydrogen-Free CVD.
abstract: Small diameter single-walled carbon nanotube (SWNT) arrays with larger bandgap are more desirable as near-infrared optical absorbers for the fabrication of high performance photovoltaic and photodetector devices. We report herein a rational approach to selective growth of well-aligned subnanometer diameter (∼84% between 0.75 and 0.95 nm) SWNT arrays with a density of 0.3-0.5 tubes/μm on quartz surfaces using solid Mo2C catalysts for short-time growth by low carbon feeding in hydrogen-free CVD. These subnanometer diameter SWNTs have a narrow chirality distribution (the ratio of (8,4), (8,5) and (7,6) is higher than 73%). During nanotube growth, only small size Mo nanoparticles are carbonized into stable Mo2C for catalyzing the growth of SWNTs through low carbon feeding rate over short time in the hydrogen-free environment, whereas larger catalysts are inactive due to underfeeding. Meanwhile, solid Mo2C catalysts are effective in reducing the chirality distributions of the as-grown SWNTs. Additionally, combining an annealing process after loading catalyst on the sapphire substrates, the average density is increased to ∼15 tubes/μm while maintaining small diameter and narrow chirality distribution. Our results offer more choices for structurally controlled growth of aligned-SWNTs, with potential applications in nanoelectronics.
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.|Division of Advanced Nanomaterials, Suzhou Institute of Nanotech and Nanobionics, Chinese Academy of Sciences , Suzhou 215123, P. R. China.|University of Chinese Academy of Sciences , Beijing 100049, P. R. China.
authors.forename: Lixing
authors.initials: L
authors.lastname: Kang
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Shibin
authors.initials: S
authors.lastname: Deng
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Shuchen
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Division of Advanced Nanomaterials, Suzhou Institute of Nanotech and Nanobionics, Chinese Academy of Sciences , Suzhou 215123, P. R. China.
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Li
authors.affiliation: Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P. R. China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang