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

Muhammad Monirul Islam,Ahmed Hichem Hamzaoui,Hajer Said,Adel Mnif,Naoki Fukata,Takeaki Sakurai,Katsuhiro Akimoto

doi:10.3390/nano12030363

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.

Highlights

Silicon (Si), an indirect bandgap semiconductor in bulk form, is considered to play vital roles in a wide range of technologies [1,2,3]
Challenges lie in the current commercial production of Si through the carbothermal reduction of silica (SiO2 ), which is associated with the high cost and environmental concerns [10]
We have performed cyclic voltammetry (CV) to of of the electrochemical process involving the reduction of investigate nano-SiO2 the to Simechanism on the graphite the electrochemical process involving the reduction of nano-SiO

Summary

Introduction

Silicon (Si), an indirect bandgap semiconductor in bulk form, is considered to play vital roles in a wide range of technologies (e.g., as electronic material in the field of electronics, and optoelectronics, and as an energy material in the field of photovoltaics, energy conversion, and energy storage devices) [1,2,3]. Solar cells, made of crystalline silicon are the prime contributor in meeting the market demand for renewable energy [4,5,6]. Silicon-based anodes, due to their high theoretical capacity (4200 mAh/g), which is higher than current commercial graphite-based anodes, are considered promising anodes for lithium-ion batteries (LIBs) [7,8,9]. Challenges lie in the current commercial production of Si through the carbothermal reduction of silica (SiO2 ), which is associated with the high cost and environmental concerns [10]. SiO2 at high-temperature molten salts [11,12,13,14]. The method has been proven cost-effective and less energy-consuming compared to the current carbothermal method.

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Conclusion