Silicon nanocrystal synthesis with the atmospheric plasma source HelixJet

Abstract

AbstractThe HelixJet, a plasma source operating under atmospheric pressure with RF power, was used for the synthesis of silicon nanoparticles (Si‐NPs) in the context of relevance in nanomedicine, sensor technology, and nanotechnology. The HelixJet was operated with a variety of He/Ar/H2/SiH4 gas mixtures to characterize the Si‐NPs in regard to their size, crystallinity, structure, and photoluminescence. Distinct varieties of nanomaterials in the size range from 3 nm to over 100 nm were synthesized depending on the operation parameters of the HelixJet. Admixture of H2 alongside high RF powers led to the formation of crystalline nanoparticles with a strong photoluminescence intensity, where the photoluminescence properties as well as the nanocrystal synthesis yield were tunable by adjustment of the synthesis parameters. Post‐synthesis in‐flight annealing allowed the formation of large crystalline nanoparticles. In addition, the experiments conducted in this study resulted in a design improvement of the HelixJet plasma source that extends the stability of the operating range. Furthermore, the added spatial separation of the He/H2 and He/Ar/SiH4 streams (SiH4 injection on‐axis) minimizes material deposition within the HelixJet and enables continuous long‐term operation.