Silicon nanocrystal synthesis with the atmospheric plasma source HelixJet

Abstract

The 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/H 2 /SiH 4 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 H 2 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/H 2 and He/ Ar/SiH 4 streams (SiH 4 injection on-axis) minimizes material deposition within the He-lixJet and enables continuous long-term operation.

Silicon quantum dots: surface matter, what next?

“…There are many methods have been developed to produce hydrogen-terminated SiQDs. It is worth to mentions: silane gas plasma synthesis (SiH 4 ), 22,23,25,88,89 electrochemical etching, [90][91][92] halosilane reduction reaction, 93,94 oxide-rich silicon thermal synthesis, [53][54][55] hydrogen silsesquioxane thermal synthesis, 4,6,11,17,[29][30][31][32][33][34][35][36][37][39][40][41][42][43][44][45][46][47][48][49][50][51][52]95 tetraethoxysilane (TES) thermal synthesis, 96,97 pulsed laser ablation, and recently also the green synthesis of rice husk thermal pyrolysis. 85 In general, the photoluminescence of the resulting material depends on the type of synthesis carried out.…”

Recent Advances in the Plasma-Assisted Synthesis of Silicon-Based Thin Films and Nanostructures

“…Compared with other APP techniques such as the plasma spray, the HelixJet requires considerably less power, thus reducing its environmental impact. A novel type of plasma jet technique, called HelixJet, was recently employed by Dworschak and coworkers [87] for the synthesis of silicon nanocrystals (Si NC). The HelixJet plasma source employs an original electrode configuration, the scheme of which is reprinted in Figure 22, in which two metal electrodes are wired around a quartz tube, forming two spiral paths.…”

Transmission Electron Microscopy Investigation of Self‐assembled 'Si/Mn4Si7‐Alloy' Janus Nanosphere Architectures Produced by a HelixJet Atmospheric Plasma Source

“…In earlier work, we described the synthesis of crystalline Si nanospheres using an atmospheric pressure plasma HelixJet, which can be operated stable and safely for a long time at low power. [ 13 ] The HelixJet produces crystalline Si nanospheres with a broad size distribution ranging from 3 to over 100 nm and offers the possibility to precisely select particles from this range with a differential mobility analyzer. In combination with an in‐flight annealing stage steel tube placed inside an oven, the formation of Mn x Si y ‐alloy nanoparticles was initially observed by transmission electron microscopy (TEM) and electron diffraction experiments.…”