Shaping electrodes for ultrahigh precision dielectrophoretic manipulation of carbon nanotubes

To achieve ultrahigh precision dielectrophoretic (DEP) manipulation of carbon nanotubes (CNTs), a novel technique is investigated both theoretically and experimentally by shaping the local geometries of nanoelectrodes to control the electrohydrodynamic behavior of CNTs. Motion trajectories and positions of CNTs assembled on electrodes are predicted based on calculated DEP forces and torques. Both simulation and experimental results show that the geometries of two opposing electrodes significantly affect the precision and robustness with which CNTs can be deposited. Investigation of an electrode array verifies our model and demonstrates that the spacing between neighboring electrode pairs should be larger than twice the width of electrodes to avoid overlapping of electric fields and imbalance of DEP forces; otherwise unequally distributed electric fields and DEP forces induce a significant number of assembly failures in the array.