Atomic Transport in Nano-Сrystalline Thin Films
Ge and B diffusion was studied in nanocrystalline Si, and Pd and Si self-diffusion was studied in nanocrystalline Pd2Si during and after Pd/Si reactive diffusion. These experiments showed that grain boundary (GB) diffusion kinetic is the same in micro-and nanoGBs, whereas triple junction (TJ) diffusion is several orders of magnitude faster than GB diffusion. In addition, GB segregation and GB migration can significantly modify atomic diffusion profiles in nanocrystalline materials, and atomic transport kinetics can be largely increased in nanograins compared to micro-grains, as well as during reactive diffusion, probably due to an increase of point defect concentration. These observations show that atomic transport in nanometric layers during reactive diffusion is complex, since GBs and TJs are moving and the proportion of GBs and TJs is changing during the layer growth.
Prof. Andreas Öchsner, Prof. Irina V. Belova and Prof. Graeme E. Murch
A. Portavoce et al., "Atomic Transport in Nano-Сrystalline Thin Films", Defect and Diffusion Forum, Vol. 367, pp. 140-148, 2016