In situ Raman spectra of SiHx, Si-F, and Si–Si vibrations from Si surfaces in HF aqueous solutions are obtained using a highly sensitive confocal microprobe Raman system. Electrochemical roughening pretreatment and laser-assisted roughening procedure enable good quality surface Raman spectra to be obtained. The surface Raman and photoluminescence spectra from the Si surface in the etching environment and the correlation of the two types of spectra are discussed. The Raman spectroscopy is shown to have high potential in serving as an important tool for in situ investigating of Si surface bonding during the etching process.

Over the past three decades, surface-enhanced Raman spectroscopy (SERS) has gone through a tortuous pathway to develop into a powerful surface diagnostic technique for in situ investigation of surface adsorption and reactions on electrodes. This review presents the recent progress achieved mainly in our laboratory on the improvement of detection sensitivities as well as spectral, temporal, and spatial resolutions. Various surface roughening procedures for electrodes of different metals coupled with maximum use of a high-sensitivity confocal Raman microscope enable us to obtain good-quality SER spectra on the electrode surfaces made from net Pt, Ni, Co, Fe, Pd, Rh, Ru, and their alloys that were traditionally considered to be non-SERS active. A novel technique called potential-averaged SERS (PASERS) has been developed for the quantitative study of electrochemical sorption. Applications are exemplified on extensively studied areas such as coadsorption, electrocatalysis, corrosion, and fuel cells, and several advantages of in situ electrochemical SERS are demonstrated. Finally, further developments in this field are briefly discussed with emphasis on the emerging methodology.

A simple and effective approach to the aqueous-phase synthesis of crystalline silver nanorods and nanowires is demonstrated, using which their diameters and aspect ratios can be effectively controlled. The synthesis involves a template-less and non-seed process to high-quality nanoparticles, which is low-cost and proceeds at moderate temperatures. The nanorods and nanowires were synthesized by the reduction of silver nitrate with tri-sodium citrate in the presence of sodium dodecylsulfonate. The concentration of tri-sodium citrate plays a critical role while sodium dodecylsulfonate, as a capping agent, only plays an assistant role in controlling the diameters and aspect ratios of the products. High-resolution transmission electron microscopy (HRTEM) and selected-area electron diffraction (SAED) investigations show that the silver nanocrystals are generated with a twinned crystalline structure. We also put forward a primary experimental model to shed light on their growth mechanisms.