Abstract
Carbon-encapsulated Ni-Sn alloy nanoparticles and aligned carbon nanofibers have been synthesized using microwave plasma enhanced chemical vapor deposition (MPECVD) with the condition of growing carbon nanotubes precusors of CH4 and H2. Catalyst doped tin dioxide film, e.g. Ni, Fe, Co, Pd, Sr, have been prepared by a sol-gel method using a spin coating technology. The coated film was dried at 150 OC and oxidized at 600 OC, 30 min to obtain an oxide film. The results with different process parameters have been examined by FESEM, XRD and HRTEM. A general observation of SEM is that not all materials encapsulate readily in carbon cage. Catalyst with doped transition element, e.g. Ni, Fe, Co, and Pd, form isolated nanocrystals encapsulated in graphitic shells. Other materials, e.g. Sr, do not embed of encapsulate. The aligned carbon nanofibers obtained by substrate bias -350V in MPECVD process has also been found. We propose the growth mechanism of an aligned carbon nanofibers with anisotropy etching. Therefore, we also proposed an growth mechanism for CEMNs and carbon nanofibers. The high etching rate due to the high negative dc bias has fabricated the two derivants of nanofiber tips with observed from HRTEM.