Enhancement of Oxidation of Silicon Carbide Originating from Stacking Faults Formed by Mode-Selective Phonon Excitation Using a Mid-Infrared Free Electron Laser.

Silicon carbide (SiC) is a promising material for wide applications due to its excellent material properties including high physical and chemical stability as well as great electronic properties of a wide bandgap. The high stability, however, makes its surface processing difficult. Especially, electrochemical processing is not well-established because of low electrochemical reactivity. Here, we show that selective phonon excitation by a mid-infrared free electron laser (MIR-FEL) enhances the anodic reactions. The selective excitation of two different vibration modes of the Si-C bond induces two different stacking faults, which act as a current path. As an application, we discovered that MIR-FEL irradiation enables Pt electroless deposition. This work reveals the interactions among phonons, lattice defects, and electrochemical reactions, encouraging further development of not only electrochemical surface processing but also a new application of MIR-FEL.