Probing trans-polyacetylene segments in a diamond film by tip-enhanced Raman spectroscopy

As an important carbon material, a nano-crystalline diamond (NCD) film is very promising in the field of science and technology. However, there are little knowledge about surface physics and chemistry of nanoscale in NCD films. Here, we perform nanoscale imaging of NCD films grown by hot filament chemical vapor deposition, using tip-enhanced Raman spectroscopy. With similar to 20 nm spatial resolution, we resolve nanoscale spatial correlations of trans-polyacetylene segments on the surface with characterized Raman modes at 1150 cm(-1) and 1480 cm(-1) that originate from the motion of conjugate polymer skeletons with a substantial contribution from the in-plane bending of carbon-hydrogen bonds and stretching vibrations of the double carbon-carbon bonds. Our work is helpful to understand the role of TPA in NCD synthesis reaction in nanoscale and improve the device application based on this material.