Grazing incidence small-angle X-ray scattering studies of the synthesis and growth of CdS quantum dots from constituent atoms in SiO₂ matrix

Grazing incidence small angle X-ray scattering was applied to study the synthesis and growth of CdS quantum dots (QDs) from Cd and S atoms implanted in SiO₂. For a dose of 10¹⁷/cm², the partial synthesis of CdS QDs occurred already during implantation, with only moderate size increase upon subsequent annealing up to T_a=1073 K. The dynamics of QD synthesis and growth were considerably different for just two times lower dose, where synthesis started only if the implanted samples were annealed at T_a = 773 K or higher, with a strong increase of the size of QDs upon annealing at higher T_a. The results suggest that high-dose implantation followed by low-temperature annealing could lead to better defined sizes and narrower size distributions of QDs.