title: Growth of close-packed semiconducting single-walled carbon nanotube arrays using oxygen-deficient TiO2 nanoparticles as catalysts.
abstract: For the application of single-walled carbon nanotubes (SWNTs) in nanoelectronic devices, techniques to obtain horizontally aligned semiconducting SWNTs (s-SWNTs) with higher densities are still in their infancy. We reported herein a rational approach for the preferential growth of densely packed and well-aligned s-SWNTs arrays using oxygen-deficient TiO2 nanoparticles as catalysts. Using this approach, a suitable concentration of oxygen vacancies in TiO2 nanoparticles could form by optimizing the flow rate of hydrogen and carbon sources during the process of SWNT growth, and then horizontally aligned SWNTs with the density of ∼ 10 tubes/μm and the s-SWNT percentage above 95% were successfully obtained on ST-cut quartz substrates. Theoretical calculations indicated that TiO2 nanoparticles with a certain concentration of oxygen vacancies have a lower formation energy between s-SWNT than metallic SWNT (m-SWNT), thus realizing the preferential growth of s-SWNT arrays. Furthermore, this method can also be extended to other semiconductor oxide nanoparticles (i.e., ZnO, ZrO2 and Cr2O3) for the selective growth of s-SWNTs, showing clear potential to the future applications in nanoelectronics.
authors.affiliation: Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, Key Laboratory for the Physics and Chemistry of Nanodevices, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871, P.R. China.
authors.forename: Lixing
authors.initials: L
authors.lastname: Kang
authors.forename: Yue
authors.initials: Y
authors.lastname: Hu
authors.forename: Lili
authors.initials: L
authors.lastname: Liu
authors.forename: Juanxia
authors.initials: J
authors.lastname: Wu
authors.forename: Shuchen
authors.initials: S
authors.lastname: Zhang
authors.forename: Qiuchen
authors.initials: Q
authors.lastname: Zhao
authors.forename: Feng
authors.initials: F
authors.lastname: Ding
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Li
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
keywords: Semiconducting single-walled carbon nanotube arrays; oxygen vacancy; preferential growth; titanium dioxide catalysts