Effect of electric field gradient on sub-nanometer spatial resolution of tip-enhanced Raman spectroscopy.

ABSTRACT: Tip-enhanced Raman spectroscopy (TERS) with sub-nanometer spatial resolution has been recently demonstrated experimentally. However, the physical mechanism underlying is still under discussion. Here we theoretically investigate the electric field gradient of a coupled tip-substrate system. Our calculations suggest that the ultra-high spatial resolution of TERS can be partially attributed to the electric field gradient effect owning to its tighter spatial confinement and sensitivity to the infrared (IR)-active of molecules. Particularly, in the case of TERS of flat-lying H₂TBPP molecules,we find the electric field gradient enhancement is the dominating factor for the high spatial resolution, which qualitatively coincides with previous experimental report. Our theoretical study offers a new

SUBMITTER: Meng L 

PROVIDER: S-EPMC4363867 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature