Silicon nanocrystal production through non-thermal plasma synthesis: a comparative study between silicon tetrachloride and silane precursors

Abstract

Silicon nanocrystals with sizes between 5 and 10 nm have been produced in a non-thermal plasma reactor using silicon tetrachloride as precursor. We demonstrate that high-quality material can be produced with this method and that production rates as high as 140 mg h(-1) can be obtained, with a maximum precursor utilization rate of roughly 50%. Compared to the case in which particles are produced using silane as the main precursor, the gas composition needs to be modified and hydrogen needs to be added to the mixture to enable the nucleation and growth of the powder. The presence of chlorine in the system leads to the production of nanoparticles with a chlorine terminated surface which is significantly less robust against oxidation in air compared to the case of a hydrogen terminated surface. We also observe that significantly higher power input is needed to guarantee the formation of crystalline particles, which is a consequence not only of the different gas-phase composition, but also of the influence of chlorine on the stability of the crystalline structure.

On the non‐thermal plasma synthesis of nickel nanoparticles

“…As a comparison, silane-containing continuous flow non-thermal plasmas can produce nanoparticles with excellent precursor utilization. [11] The data presented so far can be interpreted in light of the fact that the binding energy between the nickel cation and cyclopentadienyl (CP) rings is relatively low. The dissociation energy is 3.2 eV for the first dissociation from Ni(Cp) 2 to Ni(Cp), and 3.9 eV for the second dissociation from Ni(Cp) to Ni.…”

“…[9] Such systems can produce particles with tight and controlled size distribution (PSDs) [10] and high-quality crystalline structure. [11] Metal nanoparticles have been successfully produced using atmospheric pressure plasmas. [12] Among the advantageous properties of this approach is the fact that the particles appear to be effectively free of surface contamination.…”

High Efficiency Preparation, Structure and Properties of Silicon Nano-Crystals by Induction Plasma Method

“…The (111), (220), (311), (400), (331), and (422) diffraction peaks of diamond cubic silicon are clearly visible for both multicrystals and nano-crystals. The ensemble crystalline fraction of the samples is very high [13]. However, compared with the raw materials, the silicon nano-crystals are spherically shaped with narrow size distribution.…”

Size control, quantum confinement, and oxidation kinetics of silicon nanocrystals synthesized at a high rate by expanding thermal plasma

“…This rate is several orders higher than those deposited by other techniques such as sputtering, 15,26 pulsed laser deposition, 6 or non-thermal plasma. 16,17 The ETP-CVD is so efficient that several micrometers of the Si NCs porous layer can be deposited on the substrate in 1 s. The silane utilization efficiency is high as estimated from the slope of the blue line in Fig. 2(d).…”

“…6,[10][11][12][13][14] Si NCs are generally fabricated by sputtering, 15 pulsed laser deposition, 6 or non-thermal plasma. 16,17 Each process has its specific disadvantages, such as, limited production rate, complex and time-costly processes, post-annealing treatment, poor control over the size distribution, and low degree of surface passivation. The slow deposition rate, low throughput, and complex synthesis procedures limit the large-scale application of Si NCs.…”