In Situ Transmission Electron Microscope Observation of Carbon Nanotubes in Electric Fields

摘要

Transmission electron microscope is used to examine the movements of carbon nanotubes in electric fields. Carbon nanotubes lying along the surface of the cathode electrode start to move into alignment with the electric field vector when the field strength reaches 0.5 V/μm and become increasingly well-aligned with the vector as field strength increases. The carbon nanotubes return to their original positions when the electric field strength returns to zero. We also examine the abrupt breakdown of carbon nanotubes when the electric field is maintained at 5.5 V/μm. The corresponding breakdown emission current density is estimated as 3.4 x 10~7 A/cm~2. The distance between the nearest nanotubes standing to align with the electric field vector is approximately 2μm. This fact means that emission site density could be increased up to 3 x 10~7 points/ cm~2 (which corresponds to one tube for each 2 μm square).