Abstract

Atomic force microscopy (AFM) based nanomanipulation can align the orientation and position of individual carbon nanotubes accurately. However, the flexible deformation during the tip manipulation modifies the original shape of these nanotubes, which could affect its electrical properties and reduce the accuracy of AFM nanomanipulation. Thus, we developed a protocol for searching the synergistic parameter combinations to push single-wall carbon nanotubes (SWCNTs) to maintain their original shape after manipulation as far as possible, without requiring the sample physical properties and the tip-manipulation mechanisms. In the protocol, from a vast search space of manipulating parameters, the differential evolution (DE) algorithm was used to identify the optimal combinations of three parameters rapidly with the DE algorithm and the feedback of the length ratio of SWCNTs before and after manipulation. After optimizing the scale factor F and crossover probability Cr, the values F = 0.4 and Cr = 0.6 were used, and the ratio could reach 0.95 within 5–7 iterations. A parameter region with a higher length ratio was also studied to supply arbitrary pushing parameter combinations for individual manipulation demand. The optimal pushing parameter combination reduces the manipulation trajectory and the tip abrasion, thereby significantly improving the efficiency of tip manipulation for nanowire materials. The protocol for searching the best parameter combinations used in this study can also be extended to manipulate other one-dimensional nanomaterials.

Highlights

  • Because of their high intrinsic carrier mobility, conductivity, and mechanical flexibility [1,2,3], carbon nanotubes (CNTs) were considered as the material to be integrated into biosensors [4], nanoswitches [5], flexible circuits [6], and field-effect transistors (FETs)

  • Several methods have been developed for the array bulk of CNTs, such as the dielectrophoresis technique [7], the orientation of CNTs could be controlled by dielectrophoresis force during the CNTs depositing the substrate surface in the liquid

  • The pushing parameters, including the pushing distance, the interval between the adjacent pushing path, and the pushing step, affected the CNT pushing operation substantially. These parameters determine the shape of CNT after the pushing operation

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Summary

Introduction

Because of their high intrinsic carrier mobility, conductivity, and mechanical flexibility [1,2,3], carbon nanotubes (CNTs) were considered as the material to be integrated into biosensors [4], nanoswitches [5], flexible circuits [6], and field-effect transistors (FETs). For flexible one-dimensional nanomaterials similar to single-wall carbon nanotubes (SWCNTs), a parallel pushing vector manipulating method [33,35] was developed to translate and rotate the flexible nanowires. In this method, the tip-manipulating path was optimized by the finite element method. The experimental results indicate that only 5–7 iterations are required to obtain an optimal operating parameter combination, where the length ratio could reach 0.95 With this technique, the CNTs could be transferred with its original shape and the precise position control without optimizing each parameter.

2.2.12. MInuittiatlizoantion
Selection
AFM Experiments
Parameters Space Optimization
Conclusions
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