Mechanism of stress relaxation in Ge nanocrystals embedded in SiO2 -: art. no. 063107

Ion-beam-synthesized Ge-74 nanocrystals embedded in an amorphous silica matrix exhibit large compressive stresses in the as-grown state. The compressive stress is determined quantitatively by evaluating the Raman line shift referenced to the line position of free-standing nanocrystals. Postgrowth thermal treatments lead to stress reduction. The stress relief process is shown to be governed by the diffusive flux of matrix atoms away from the local nanocrystal growth region. A theoretical model that quantitatively describes this process is presented. (C) 2005 American Institute of Physics.