Enhanced Diffusion of Silver Atoms on the Surface of Nanoparticles at Low Temperatures

Abstract

Microstructure development of 35 nm silver nanoparticles during the low temperature sintering was examined in situ as the ambient temperature increased from room temperature up to 450 آ°C using Xray diffraction and electron microscopy techniques. Measured particle size increased rapidly up to ∼90 nm in the temperature range between 130 and 250 آ°C, which is thought to be from the atomic diffusion on the surfaces of nanoparticles. On the other hand, further increase of the annealing temperature results in little or almost no change in the grain size. Therefore, the sintering effect due to the surface diffusion of silver atoms is active only on the surface of nanoparticles whose size is less than ∼90 nm, indicating enhanced atomic mobility of silver atoms on the surface of nanoparticles.