TEM images with different magnifications showing a sample produced by sputtering (see text) and annealed for 2 h in Ar atmosphere at 1323 K. The SiO2 films are labeled as I in (a) and (b), while the film containing the Ge nanoparticles is labeled as II. The complete layer stack is shown in (a), where the glue is labeled as III. The interface between the SiO2 and the SiO2 film with Ge nanoparticles is shown in (b). A crystalline nanoparticle is seen in (c). Scale bars correspond to 0.4 µm in (a), 200 Å in (b) and 50 Å in (c).