Growth of glass-embedded Cu nanoparticles: A low-frequency Raman scattering study.

Several populations of Cu spherical nanoparticles grown in a silicate glass at different temperatures with respect to the glass transition temperature were studied using high-resolution, low-frequency Raman scattering and optical absorption. The analysis of the spectra shows that the annealing of the doped glass at temperatures close to Tg leads to the formation of metallic copper nanoparticles with high crystallinity, whereas lower-temperature and higher-temperature annealings result in the formation of poorer nanoparticle assemblies in terms of size distribution and/or nanocrystallinity. It is also shown that in the case where the optical data do not unambiguously reveal the presence of metallic Cu nanoparticles, the Raman probe enables us to probe their presence as a result of the resonance process. [ABSTRACT FROM AUTHOR]