Plasmon-Enhanced Near-Field Optical Spectroscopy of Multicomponent Semiconductor Nanostructures

Abstract

Multicomponent semiconductor nanostructures were studied by local spectral analysis based on surface-enhanced Raman scattering by semiconductor nanostructures located on the surface of an array of Au nanoclusters near the metallized tip of an atomic force microscope. In the gap between the metal nanoclusters and the tip, where a semiconductor nanostructure is located, there is a strong increase in the local electric field (hot spot), resulting in a dramatic enhancement of the Raman scattering signal. An unprecedented enhancement of the Raman scattering signal by two-dimensional (over 10⁸ for MoS₂) and zero-dimensional (10⁶ for CdSe nanocrystals) semiconductor nanostructures was achieved. The use of the method for mapping the Raman scattering response of a multicomponent system of MoS₂ and CdSe made it possible to identify components with a spatial resolution far exceeding the diffraction limit.