| AVS 54th International Symposium | |
| Thin Film | Friday Sessions |
| Session TF2-FrM |
| Session: | Nanoparticles |
| Presenter: | Y.F. Guan, The University of Tennessee, Knoxville |
| Authors: | Y.F. Guan, The University of Tennessee, Knoxville A.V. Melechko, Oak Ridge National Laboratory A.J. Pedraza, The University of Tennessee, Knoxville P.D. Rack, The University of Tennessee, Knoxville |
| Correspondent: | Click to Email |
We present a non-lithographic technique that produces organized nanoscale nickel catalyst for carbon nanofiber growth on a silicon substrate. This technique involves three consecutive steps: first, the substrate is laser-irradiated to produce a periodic nanorippled structure; second, a thin film of nickel is deposited using glancing angle ion beam sputter-deposition, followed by plasma heat-treatment; and third, a catalytic dc plasma enhanced chemical vapor deposition (PECVD) process is conducted to produce the vertically aligned carbon nanofibers (VACNF). The nickel catalyst is distributed along the laser induced periodic surface structures (LIPSS), and the Ni particle dimension varies as a function of the location on the LIPSS and is correlated to the nanoripple dimensions. The glancing angle, the distance between the collimators, and the total deposition time all play important roles in determining the final catalyst size and subsequent carbon nanofiber property. Due to the gradual aspect ratio change of the nanoripples across the sample, Ni catalyst nanoparticles of different dimensions were obtained. After the PECVD process, it was observed that in order for the carbon nanofibers to grow, the nickel catalyst dimension should be larger than a certain critical value of ~ 25 nm, below which, the Ni is insufficient to sustain carbon nanofiber growth.