Formation of isolated Ge nanoparticles in thin continuous Ge/SiO2 multilayers

Abstract

A simple and reliable e-gun assisted physical vapor deposition technique was used to deposit alternatively amorphous thin (2 nm) continuous layers of Ge and SiO2 in high vacuum. Our goal was to explore whether annealing of these multilayers in inert atmosphere at rather low temperature (525 °C) will produce isolated sphere-like Ge nanoparticles embedded in amorphous SiO2 matrix suitable for solar cell applications, and which analyzing technique will provide the most comprehensive information on this composite material. All samples were characterized by the following complementary techniques: grazing incidence X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM) and grazing incidence small-angle X-ray scattering (GISAXS). All techniques confirm Ge nanoparticles formation. It was demonstrated that GISAXS provides the most detailed description of the particle size and shape on a macroscopic scale.