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Single-molecule tip-enhanced Raman spectroscopy of C 60 on the Si(111)-(7 × 7) surface.
- Source :
-
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2024 Aug 14; Vol. 26 (32), pp. 21325-21331. Date of Electronic Publication: 2024 Aug 14. - Publication Year :
- 2024
-
Abstract
- Tip-enhanced Raman spectroscopy (TERS), combined with low-temperature scanning tunnelling microscopy (STM), has emerged as a highly sensitive method for chemical characterization, offering even sub-molecular resolution. However, its exceptional sensitivity is generally limited to molecules adsorbed onto plasmonic surfaces. Here we demonstrate single-molecule TERS for fullerene (C <subscript>60</subscript> ) adsorbed on the Si(111)-(7 × 7) reconstructed surface. Distinct adsorption geometries of C <subscript>60</subscript> are manifested in the TERS spectra. In addition, we reveal that formation of a molecular-point-contact (MPC) drastically enhances Raman scattering and leads to the emergence of additional vibrational peaks, including overtones and combinations. In the MPC regime, the anti-Stokes peaks are observed, revealing that vibrationally excited states are populated through optical excitation of the MPC junction, whereas showing no significant vibrational heating by current flow via inelastic electron-vibration scattering. Our results will open up the possibility of applying TERS for semiconducting surfaces and studying microscopic mechanisms of vibrational heating in metal-molecule-semiconductor nanojunctions.
Details
- Language :
- English
- ISSN :
- 1463-9084
- Volume :
- 26
- Issue :
- 32
- Database :
- MEDLINE
- Journal :
- Physical chemistry chemical physics : PCCP
- Publication Type :
- Academic Journal
- Accession number :
- 39082139
- Full Text :
- https://doi.org/10.1039/d4cp01803f