In Situ Atomic Force Microscopy and Electrochemical Quartz Crystal Microbalance Studies on the Electrodeposition and Oxidation of Silicon

Abstract

In this paper, we investigated how the anion of an ionic liquid (IL) affects nanostructure of electrode/electrolyte interface and subsequently the deposition process of silicon. For this purpose, ILs with the same cation 1-butyl-1-methylpyrrolidinium and various anions, namely, tris(pentafluoroethyl) trifluorophosphate ([Py1,4]FAP), bis(trifluoromethylsulfonyl)amide ([Py1,4]TFSA), and bis(fluorosulfonyl)amide ([Py1,4]FSA) were chosen. Cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM) were used to study the electrochemical processes. Raman spectroscopy and in situ atomic force microscopy (AFM) were used to evaluate the changes in the ILs on addition of SiCl4 and to probe the changes in the Au (111)/electrolyte interface, respectively. From cyclic voltammetry and EQCM measurements, it was found that the electrochemical processes changed significantly on changing the anion. However, from Raman spectroscopy a few spectral changes related to vibrational modes of the employed anions were...