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Germanium islands were produced by magnetron sputtering of Ge onto monocrystalline silicon, where effective Ge thickness was varied from 2 to 6 nm. The shape and distribution of the islands were investigated using grazing incidence small-angle X-ray scattering (GISAXS) and atomic force microscopy (AFM). The GISAXS experiments revealed that Ge islands height varied from 3 to 6 nm and the lateral dimensions of 10 to 20 nm. However, AFM results indicated bigger sizes, and this is attributed to different resolution ranges of the two experimental techniques. Tuning the deposition conditions and subsequent treatments may allow the control of the size and shape of the islands and consequently the energy levels that drive the light absorption spectra. Such simple process could be of great interest for the third generation of solar cells, aiming to very high efficiencies at low cost. |