Real-Time Optical Microspectroscopy and Activation Energy of Ag Nanoparticle Growth in Thin Silica Films

Significant progress in understanding noble metal species transformations in dielectrics can be achieved from the real-time monitoring of optical properties during material processing. In this work, in situ optical microspectroscopy is employed to study the Ostwald stage of Ag nanoparticle (NP) growth in nano-thin SiO2 films on soda glass substrates during heat treatment in air in the 550 – 600°C range. The evolution of Ag NP size is assessed in the framework of Mie extinction and crystal growth theories. An Arrhenius-type analysis of a set of time-dependent isotherms yields an activation energy of 1.9 eV for the Ostwald growth.