Study of Structural and Optical Properties of Electrodeposited Silicon Films on Graphite Substrates

Abstract

Silicon (Si) films were deposited on low-cost graphite substrates by the electrochemical reduction of silicon dioxide nanoparticles (nano-SiO2) in calcium chloride (CaCl2), melted at 855 °C. Cyclic voltammetry (CV) was used to analyze the electrochemical reduction mechanism of SiO2 to form Si deposits on the graphite substrate. X-ray diffraction (XRD) along with Raman and photoluminescence (PL) results show that the crystallinity of the electrodeposited Si-films was improved with an increase of the applied reduction potential during the electrochemical process. Scanning electron microscopy (SEM) reveals that the size, shape, and morphology of the Si-layers can be controlled from Si nanowires to the microcrystalline Si particles by controlling the reduction potentials. In addition, the morphology of the obtained Si-layers seems to be correlated with both the substrate materials and particle size of the feed materials. Thus, the difference in the electron transfer rate at substrate/nano-SiO2 interface due to different applied reduction potentials along with the dissolution rate of SiO2 particles during the electrochemical reduction process were found to be crucial in determining the microstructural properties of the Si-films.

Formation of silicon layer through aluminothermic reduction of quartz substrates

“…On the other hand, for the sample with a 4 µm thick Al layer, the Raman peak shows a right Frontiers in Materials frontiersin.org shift compared to the c-Si sample, presumably due to increased compressive strain in the sample. It is to be noted that the position of the Raman peaks in Si materials can be affected by the laser heating during measurement (Islam et al, 2018;Islam et al, 2022), or local stress. Nevertheless, shifting of the optical phonon-band to a lower wavenumber in samples obtained with thinner Al-layers compared to that of single-crystal Si (bulk) roughly suggests the size-related quantum confinement effect due to the formation of microcrystalline or nanocrystalline phases (Fukata et al, 2005;Ristić et al, 2009).…”

Silicon Electrodeposition for Microelectronics and Distributed Energy: A Mini-Review

“…In [5], the effects were studied of substrate material (Ag, Mo, C), electrodeposition potential, and particle size distribution of SiO2 on the morphology of silicon deposits obtained by electrolysis of a CaCl2-CaO-SiO2 melt at a temperature of 855 °C. A continuous photosensitive silicon film 180 μm thick was obtained on graphite at the lowest cathodic overvoltage.…”

“…Silicon-based materials are especially in demand for the creation of microelectronics and distributed energy devices. In particular, the possibility of using silicon and siliconbased materials in solar energy conversion devices and energy-storage devices is being actively studied [4,5]. Silicon-based materials remain the basis of photoconverters, and the replacement of graphite anodes with silicon can increase the capacity of lithium-ion current sources by an order of magnitude (theoretically, from 372 to 4200 mAh g −1 [4,6]).…”

Electroreduction of silicon from the NaI–KI–K2SiF6 melt for lithium-ion power sources

“…Silicon and silicon-based materials are becoming widely used in microelectronics, metallurgy and power generation [1]. Silicon materials to be used in devices for solar energy conversion, accumulation and storage are being actively developed [2][3][4]. Silicon is a promising anode material for lithium-ion power sources because its specific lithium-adsorption capacity (4200 mAh•g -1 ) is by an order of magnitude higher than those of graphite-containing anode materials (372 mAh•g -1 ) [5][6][7].…”