Structure and Dynamics of Ge in the Si–SiO[sub 2] System: Implications for Oxide-Embedded Ge Nanoparticle Formation

Using gradient corrected periodic density functional theory calculations, we have investigated the structure, energetics, bonding, and diffusion of Ge in bulk α-quartz and amorphous matrices as well as at the interface. Our calculations show that Ge atoms undergo migration in with a moderate barrier and prefer to remain in the Si part near the interface via site exchange reaction with Si lattice atoms, while the kicked-out Si atoms are preferentially incorporated into the matrix. We also discuss implications of the Ge–Si exchange process for Ge nanoparticle formation in an oxide matrix.