Substrates for combined surface enhanced Raman spectroscopy and photon tunneling measurements

Imaging and certain spectroscopic capabilities of the photon scanning tunneling microscope (PSTM) are reported for laser sources at different wavelengths in the visible spectrum. The results yield PSTM images of silver microstructures and surface enhanced Raman spectra of benzoic acid and cobalt phthalocyanine acquired by the PSTM for these microstructures.

Three types of samples are studied: photoresist gratings, silver-coated gratings, and isolated silver particles. PSTM images of all three types of sample are presented. Results of using a conventional lens system and spectrometer show that both the silver-coated gratings and the isolated particles are good samples for surface enhanced Raman spectroscopy (SERS). SERS data acquired by the PSTM/spectrometer system for these samples show that sufficiently intense spectra are obtained to unambiguously identify the target compounds. This research provides a basis for further work to determine if the PSTM can be an effective tool for topographical chemical mapping.