Effect of magnetic field on Ni nanoclusters prepared via a combined plasma-enhanced chemical vapor deposition and radio frequency sputtering

摘要

Nickel nanoparticles were prepared by a co-deposition technique via radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) and radio frequency (RF) sputtering methods using a Ni target and acetylene gas. To prevent the prepared nanoparticles from agglomeration and in order for the nucleus of the nanocluster to be formed, a DLC film was made as host. We fixed the RF power at 300 W and the deposition time at 30 min. We prepared four different nickel samples by varying the initial pressure of acetylene gas in the chamber. It is shown as the amount of nickel increases, the electrical resistance decreases where the structure is transformed from a nanoparticle form to a nanocluster form. The nanoclusters have a cone structure, because the initial nanoparticles serve as nuclei for nanoclusters, and deposition is carried out vertically. By applying a magnetic field, it was found that the cluster structure gives a better response to it. The absorbance value at 800 nm was improved from 0.5% for the pure nanoparticle sample (#1) to 6.4% for the nanocluster structure (#4). As a result, the nanocluster structure is more suitable for magnetic sensors.