Surface- and Tip-Enhanced Raman Scattering by CdSe Nanocrystals on Plasmonic Substrates

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Cadmium selenide (CdSe) nanocrystals (NCs) are crucial in optoelectronics.
• Understanding their optical response is key for advanced applications.
• Surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) offer powerful spectroscopic tools.

Purpose of the Study:

• To present recent findings on the optical response of spherical CdSe NCs.
• To explore the capabilities of SERS and TERS for characterizing CdSe NCs.
• To demonstrate nanoscale phonon property analysis.

Main Methods:

• Utilizing surface-enhanced Raman scattering (SERS) with plasmonic substrates.
• Employing tip-enhanced Raman scattering (TERS) combining Raman spectroscopy and atomic force microscopy (AFM).
• Investigating resonant enhancement by aligning localized surface plasmon resonance (LSPR) with laser excitation energy.

Main Results:

• SERS enables detection of mono- and submonolayer CdSe NC coatings through phonon response enhancement.
• TERS provides nanoscale spatial resolution for investigating phonon properties of CdSe NCs.
• Gap-mode TERS further enhances Raman scattering for optical phonon modes, enabling single nanostructure analysis.

Conclusions:

• SERS and TERS are effective techniques for characterizing the optical and phonon properties of CdSe NCs.
• These methods allow for high-resolution analysis at the nanoscale.
• The findings open new avenues for optical characterization of single semiconductor nanostructures.