Chemical analysis of ligand-free silicon nanocrystal surfaces by surface enhanced Raman spectroscopy (original) (raw)

Surface enhanced Raman spectroscopy (SERS) was used to probe the surface chemistry of chlorine-terminated silicon nanocrystal (Si-NC) surfaces in an air-free environment. SERS effect was observed from the thin films of AgxO using 514 nm laser wavelength. When a monolayer of Si-NCs were spin-coated on AgxO SERS substrates, a very clear signal of surface states, including Si-Clx, and Si-Hx were observed. Upon air-exposure, we observed the temporal reduction of Si-Clx peak intensity, and a development of oxidation-related peak intensities, like Si-Ox and Si-O-Hx. In addition, first, second and third order transverse optical (TO) modes of Si-NCs were also observed at 519, 1000 and 1600 cm−1, respectively. As a comparison, Raman analysis of a thick film (> 200 nm) of Si-NCs deposited on ordinary glass substrates were performed. This analysis only demonstrated the first TO mode of Si-NCs, and the all the other features originated from SERS enhancement did not appear in the spectrum. These results conclude that, SERS is not only capable of single-molecule detection, but also a powerful technique for monitoring the surface chemistry of nanoparticles.

Sign up for access to the world's latest research.

checkGet notified about relevant papers

checkSave papers to use in your research

checkJoin the discussion with peers

checkTrack your impact