Molecular Dynamics Simulation Study of Carbon Nanotube Welding under Electron Beam Irradiation

Abstract

The simulation of electron beam induced welding of crossed carbon nanotubes is considered with classical molecular dynamics simulations. Covalent junctions are predicted to form between various types of carbon nanotubes that contain many defects and are likely to be representative of experimentally welded nanotubes under highly nonequilibrium synthesis conditions. The effect of the junction structure and hydrogen termination of dangling bonds on the mechanical responses of the junctions is also considered.

Ion and electron irradiation-induced effects in nanostructured materials

“…II, the electron-atom collision time is extremely short ͑10 −21 s, Ref. 72͒, so that the impacts of energetic electrons onto carbon nanosystems can be modeled 43,46,210,212,271,289 by assigning some kinetic energy to a carbon atom in the atomic network and then by using the MD method to simulate the subsequent atom motion to understand if the impact gave rise to the formation of a defect. The orientation of the initial velocity vector can be chosen either randomly if the main goal is to simulate the response of the system to a prolonged irradiation or in the direction, 43 which will more likely result in the formation of a defect, if the defect formation energy is the quantity of interest.…”

“…The use of a highly localized electron beam with diameter of several nanometers, and high temperature annealing of the samples after irradiation, should minimize the damage outside the junction area, which is particularly important for applications of SWNT-based circuits in nanoelectronics. Simulations 289 showed that the welded nanotube structures should be mechanically stable in spite of many defects near the contact area.…”

Thermal conductivity of an ultrathin carbon nanotube with an X-shaped junction

“…[20][21][22][23][24] Based on the topology and Euler's theorem, 25,26 the structures of T-, Y-, and X-shaped junctions of CNT were proposed theoretically and their stabilities have been validated theoretically. 2,24,27,28 These junctions have a negative Gaussian curvature associated with the presence of sevenfold or eightfold rings, in contrast to fullerenes which have a positive Gaussian curvature due to the introduction of fivefold rings.…”

Surface reconstructions and stability of X-shaped carbon nanotube junction

“…Crossed SWCNTs are usually nanowelded to generate X junction under electron-or ion-beam irradiation, where the irradiation-induced vacancies play a crucial role in the merging processes. [9][10][11][12] However, these high-energy process may not be desirable for nanoscale device applications because of uncontrollable bonding disorder in the joints. Our previous work found that the ideal X junctions may be formed by heating two crossed tubes without preexisting structural defects, and that the resulting X junctions only contain topological defects such as pentagons and heptagons.…”