Tip-Enhanced Raman Spectroscopy Provides 1-Nm Resolution

Tip-enhanced resonance Raman spectroscopy (TERRS) has been demonstrated by research. The results suggest that TERRS could offer a new approach for the atomic-scale optical characterization of local electronic states.

On extremely thin zinc oxide layers that were epitaxially grown on an Ag(111) surface and in which both physical and chemical enhancement mechanisms were in operation, the researchers showed TERRS. The underlying process was investigated by altering the localized surface plasmon resonance in a scanning tunneling microscope junction and recording various-thickness zinc oxide films that displayed a marginally different electronic structure.

The study team showed that the Tip-enhanced resonance Raman spectroscopy (TERRS) intensity was influenced by the local electronic resonance of the zinc oxide/Ag(111) interface in conjunction with scanning tunneling spectroscopy (STS). The researchers also demonstrated how the tip-surface distance affected the spatial resolution of TERRS, which could reach nearly 1 nm in the tunneling regime.

Resonance Raman spectroscopy is an effective instrument for highly sensitive chemical structure analysis, but the diffraction limit has limited its spatial resolution to a few hundred nm. Takashi Kumagai’s Fritz-Haber team got around this restriction by using localized surface plasmon excitation to accomplish 1-nm precision with TERRS and extreme field confinement at a metal tip apex.

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