LAUSR

Abstract Amorphous Ge/SiO2 multilayers were deposited in a high vacuum by an e-gun assisted physical vapor deposition technique with continuous Ge layers either 2 or 4 nm thick, separated by 2 nm thick SiO2 layers. The aim was to explore whether annealing of these multilayers at a rather low temperature will produce Ge nanoparticles suitable for solar cell applications. All samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (ARM), transmission electron microscopy (TEM) in cross-section, grazing incidence X-ray diffraction, Raman spectroscopy and grazing incidence small-angle X-ray scattering (GISAXS). It is found that annealing of very thin continuous amorphous Ge layers will lead to mostly spherical crystalline nanoparticles (NPs) of the desired size. On the other hand, from thicker Ge layers, a bimodal distribution is obtained consisting of smaller sphere-like and larger oblate spheroids, as confirmed by a calculated simulation.