Characteristics of silicon nanoparticles depending on h2 gas flow during nanoparticle synthesis via co2 laser pyrolysis

초록

Silicon nanoparticle is a promising material for electronic devices, photovoltaics, and biological applications. Here, we synthesize silicon nanoparticles via CO<inf>2</inf> laser pyrolysis and study the hydrogen flow effects on the characteristics of silicon nanoparticles using high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and UV-Vis-NIR spectrophotometry. In CO<inf>2</inf> laser pyrolysis, used to synthesize the silicon nanoparticles, the wavelength of the CO<inf>2</inf> laser matches the absorption cross section of silane. Silane absorbs the CO<inf>2</inf> laser energy at a wavelength of 10.6 μm. Therefore, the laser excites silane, dissociating it to Si radical. Finally, nucleation and growth of the Si radicals generates various silicon nanoparticle. In addition, researchers can introduce hydrogen gas into silane to control the characteristics of silicon nanoparticles. Changing the hydrogen flow rate affects the nanoparticle size and crystallinity of silicon nanoparticles. Specifically, a high hydrogen flow rate produces small silicon nanoparticles and induces low crystallinity. We attribute these characteristics to the low density of the Si precursor, high hydrogen passivation probability on the surface of the silicon nanoparticles, and low reaction temperature during the synthesis. © Materials Research Society of Korea, All rights reserved.

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