title: Reversible Tuning of Individual Carbon Nanotube Mechanical Properties via Defect Engineering.
abstract: The structural defects that inevitably exist in real-world carbon nanotubes (CNTs) are generally considered undesirable because they break the structural perfection and may result in drastically degraded CNT properties. On the other hand, the deliberate defect introduction can provide a possibility to tailor the tube mechanical properties. Herein, we present a fully controllable technique to handle defects by using in situ transmission electron microscopy (TEM). Young's modulus, quality factor of the resonation and tensile strength of CNTs can be controllably, reversibly, and repeatedly tuned. Parallel high-resolution visualizing of structural defects suggests that the property tuning cycles are primarily attributed to the reversible conversion of defects at the atomic scale: the defects are created in the form of vacancies and interstitials under electron irradiation, and they vanish through the recombination via current-induced annealing. For applications, such as reversible frequency-tuned CNT resonators, this defect-engineering technique is demonstrated to be uniquely precise; the frequency may be tuned with 0.1%/min accuracy, improved by 1 order of magnitude compared with the existing approaches. We believe that these results will be highly valuable in a variety of property-tunable CNT-based composites and devices.
authors.affiliation: Department of Materials Science and Engineering, College of Materials, and Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University , Xiamen, Fujian 361005, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Materials Science and Engineering, College of Materials, and Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University , Xiamen, Fujian 361005, China.
authors.forename: Longze
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Materials Science and Engineering, College of Materials, and Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University , Xiamen, Fujian 361005, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: International Centre for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS) , Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan.
authors.forename: Dmitri
authors.initials: D
authors.lastname: Golberg
authors.affiliation: Department of Materials Science and Engineering, College of Materials, and Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University , Xiamen, Fujian 361005, China.
authors.forename: Ming-Sheng
authors.initials: MS
authors.lastname: Wang
keywords: In situ transmission electron microscopy (TEM); carbon nanotube (CNT) resonator; defect engineering; mechanical properties tuning; property-structure relationship; resonant frequency