Ion beam synthesis and characterization of Ge nanoparticles in SiO2

Ge quantum dots embedded in SiO2 have been obtained by implantation of Ge ions in the 10(16)-10(17) cm(-2) dose range, followed by post-implantation annealing in the temperature range T-a = 300-1000 degrees C. Using Rutherford back-scattering, grazing incidence X-ray diffraction and grazing incidence small angle X-ray scattering it was found that Ge-QDs are synthesized as discrete, spherical QDs, with radius ranging from 1.7 to 10 nm, depending on dose and T-a. For T-a above 800 degrees C the Ge atom diffusion becomes considerable, leading to a strong increase of both size and size distribution of Ge QDs, but still without sizeable loss of Ge atoms from the implanted layer