Studies on the formation of Si nanocrystals in SiO2 by Ge ion implantation

Ge ions are implanted on thermally grown SiO2 layer at various doses and post-annealed in inert gas ambient. X-ray diffraction and Raman scattering studies on implanted samples reveal that Ge nanocrystals of sizes 4–13 nm are formed embedded in SiO2 for Ge+ ion fluence in the range 3 × 1016−2 × 1017 cm−2. At high dose (⩾1 × 1017 cm−2), in addition to Ge NCs, Si NCs are formed at the interface between Si and SiO2 layer as a result of ion impact. Optical Raman spectra show distinct peak at ∼503 cm−1 corresponding to the Si NCs. Average size of the Si NCs are smaller than the average size of the Ge NCs.