Influence of the sintering temperature on morphology of alloy germanium-tin nanoparticles synthesized by spark discharge

Abstract

Alloy GeSn airborne nanoparticles (NP) with the rate of atomic content of Sn to Ge 30 % were produced by spark discharge during simultaneous erosion of germanium and tin electrodes in atmosphere of argon of purity 6.0. Then NP were moved by gas flow to a tube furnace, which were mounted directly after discharge chamber, and sintered at temperatures from 25 to 750 °C. The change of morphology, element composition and crystal structure of NP were investigated using transmission electron microscopy (TEM) with energy dispersive X-ray analysis (EDX), aerosol spectrometer and Fourier-transform infrared spectroscopy (FTIR). Agglomerates of predominantly amorphous primary NP with the mean size of 7 nm were obtained at low sintering temperatures of the tube furnace (25 and 200 °C). High temperature (550 and 750 °C) flow-through thermal sintering of NP agglomerates resulted in production of individual crystal NP with an average size of 28 nm with various crystal structures.