Nonuniform growth of embedded silicon nanocrystals in an amorphous matrix.
The phase transformation of a metastable system occurs when islands of a second stable phase form and grow. The growth velocity of the islands controls the kinetics of the phase transformation. In this work we consider the amorphous-to-crystalline transformation in silicon as the prototype of a solid-to-solid transformation. The results of atomistic simulations are fit using an analytic model for the growth of [100]-oriented nanosized crystalline fibers embedded into an amorphous matrix. We demonstrate that the radius of the island does not grow, in general, at constant velocity. On the contrary, we identify a decelerated motion that is due to anisotropic effects of the crystal grain. Such a nonuniform growth should be taken into account in the modeling of solid-to-solid crystallization.
Mattoni
Alessandro
A
SLACS-INFM/CNR Sardinian Laboratory for Computational Materials Science and Department of Physics, University of Cagliari, Cittadella Universitaria, I-09042 Monserrato Ca, Italy. alessandro.mattoni@dsf.unica.it
Colombo
Luciano
L