Tip enhanced Raman spectroscopy evidence for amorphous carbon contamination on gold surfaces

• Published in: Surface science Vol. 604; no. 7; pp. 701 - 705
• Main Authors: Chaigneau, Marc, Picardi, Gennaro, Ossikovski, Razvigor
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.04.2010; Elsevier
• Subjects: Carbon; Carbon contamination; Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Contaminants; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fluctuation; Gold; Grain boundaries; Material chemistry; Near-field optics; Noble metals; Physics; Raman spectroscopy; Scanning tunnelling microscopy (STM); Spectra; Tip enhanced Raman spectroscopy (TERS); Near-field optics; Scanning tunnelling microscopy (STM); Carbon contamination; Au; Tip enhanced Raman spectroscopy (TERS); Scanning tunneling microscopy; Gold; Raman spectra; Transition elements; Amorphous state; Carbon
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2010.01.018

We show that the origin of the spectral fluctuations frequently observed in tip enhanced Raman spectroscopy (TERS) experiments can be mainly related to the presence of surface-contaminating amorphous carbon-based species. We have monitored the spectral fluctuations originating from the sharp metallic tips used as apertureless near field probes, as well as from commonly used noble metal substrates. A correlation between the tip surface roughness and the carbon-based spectral fluctuations has been revealed. An Au-(1 1 1) bare substrate has been mapped with sub-wavelength resolution by TERS, evidencing the localization of the carbon contaminants on the surface steps and grain boundaries.