Ion Implantation Synthesis and Characterization of Cobalt Nanodots

摘要

A study of the synthesis of Co nanodots by ion implantation was carried out. Silica was implanted with 35 keV Co~+ ion beams with doses of 8x10~(15), 3x10~(16) and 1x10~(17) at/cm~2 and transmission electron microscopy revealed the presence of spherical nanodots in these samples. Annealing in vacuum at 900 ℃ was used to change the size distribution of the nanodots. The annealed samples presented an absorption band related to the plasmon collective excitation of the metallic nanodots that redshifted for higher Co contents. The magnetic character of the samples was revealed by magnetic force microscopy measurements that showed the presence of randomly distributed structures with defined magnetization in the case of annealed samples. This work shows the feasibility of synthesizing Co nanodots with controlled size distribution.