Nanoscale imaging of carbon nanotubes using tip enhanced Raman spectroscopy in reflection mode

An apertureless tip enhanced Raman spectrometer in reflection mode geometry is demonstrated. A spatial resolution as small as 30 nm was achieved. This was implemented by placing a sharp gold tip near the single wall carbon nanotubes using an atomic force microscope (AFM). The tip was illuminated from the same side of the sample which eliminated the need for a transparent substrate. The tip was maintained at a distance of a few nanometers using a quartz tuning fork. The Raman signal was collected from the G peak of the single wall carbon nanotubes using a single photon detecting module and topography image was acquired by the AFM.