Characterization of Si–Ge alloy nanocrystals produced in a non-thermal plasma reactor

In this paper we demonstrate the synthesis of high quality crystalline silicon–germanium alloy nanoparticles using the combination of a non-thermal plasma reactor and chlorinated precursors. The produced particles have potential applications in several fields including for the production of advanced thermoelectric materials. The use of silicon and germanium tetrachloride has clear advantages with respect of hydrogenated precursors (silane and germane) from both the cost and safety points of view. Nanocrystals smaller than 10 nm have been produced with excellent control over the alloy composition. Characterization by Raman, XRD and TEM confirm that the produced material is not composed of a mixture of silicon and germanium nanoparticles, but rather by an ensemble of crystals in which each particle is composed of an alloy of silicon and germanium.