Electrodeposition and characterization of silicon films obtained through electrochemical reduction of SiO2 nanoparticles

We have reported electrodeposition of silicon films on metal substrates obtained through electrochemical reduction of silicon dioxide nanoparticles (SiO2-NP) at high temperature of 855 °C in the calcium chloride (CaCl2) melt. Electrodeposition was conducted using a three-electrode based electrochemical cell. Reduction of the SiO2 was found possible with applying a negative potential of 0.9 V or more negative on the metal substrate with respect to the graphite reference electrode. Mechanism of the reduction and electrodeposition process was discussed using cyclic voltammetry (CV), and chronoamperograms (CA) techniques in relation to the applied reduction potentials during experiments. Raman spectroscopy, and X-ray diffraction method confirmed formation of the Si-film on the silver (Ag) substrate using the electrodeposition technique. Effect of the various reduction potentials on the properties of the formed Si layer was studied using Raman spectroscopy, photoluminescence (PL), and Scanning electron microscopy (SEM). Crystallinity of the electrodeposited Si-films were found to be correlated with the reduction potential. Nanocrystalline Si (nc-Si) film was obtained through electrodeposition with lower reduction potentials, while higher reduction potential was found to be effective to get Si-films with uniform crystalline quality, and better morphology. Effect of the substrate materials on the electrochemical reduction of SiO2 was also investigated.