Effect of annealing temperature on the copper nanoparticles deposited on the silicon nanoporous pillar array

Copper/silicon nanocomposite system (Cu/Si-NPA) is prepared by immersion plating Cu nanoparticles on silicon nanoporous pillar array (Si-NPA). The Cu/Si-NPA samples are heated under nitrogen for 2 h at elevated temperatures of 400 °C, 600 °C, and 800 °C. The morphological changes of Cu nanoparticles before and after heat treatments are characterized by SEM. The crystallinity and the average size of Cu nanoparticles before and after heat treatments are studied by XRD. The results show that two possible mechanisms, Ostwald ripening, and particle migration and coalescence, are believed to be responsible for the ripening of annealed Cu nanoparticles at different annealing temperatures.