Fabrication and Characterization of Cu-Co Alloy Nanoparticles via Pulsed Laser Dewetting

The fabrication and characterization of Cu[Copper]-Co[Cobalt] alloy nanoparticles are addressed in this thesis. First, Cu-Co alloy thin films with total thickness of ~10 nm [nanometer] were deposited on both 100 nm SiO₂ [silicon dioxide] coated silicon wafers and quartz substrates using RF magnetron sputtering system. Three structures were studied in this work: (1) ~10 nm co-sputtered Cu-Co alloy thin film. (2) ~5 nm (at center) Cu thin film covered by ~5 nm (at center) Co thin film. (3) ~5 nm (at center) Co thin film covered by ~5 nm (at center) Cu thin film. In addition, ~10 nm pure Cu and Co thin films were also prepared on the three substrates described above for comparison with the alloy. EDS, Filmetrics F20-UV thin film analyzer, and Cary 5000 (Varian Inc.) were used for thin films composition and optical properties analysis. After that, thin films were irradiated in air by Nd:YAG [neodymium-doped yttrium aluminum garnet] laser to form Cu-Co particles. The particles morphology was then characterized by SEM [Scanning Electron Microscope]. Composition and optical properties were also studies on particles.

The analysis results demonstrate that the dewetting evolution is tunable by adjusting the alloy composition or thin film structure. Particles size distribution is also affected by composition and structure. The optical measurement reveals that particles at Cu-rich edge on Co top Cu bottom sample show an obvious Surface Plasmon Resonance phenomenon.