Methods to fabricate and recycle plasmonic probes for ultrahigh vacuum scanning tunneling microscopy-based tip-enhanced Raman spectroscopy

摘要

Scanning tunneling microscopy-based tip-enhanced Raman spectroscopy (TERS) is a powerful analytical technique for surface characterization, providing both topological and chemical information with sub-nm spatial resolution, well below the diffraction limit of light. In order to take advantage of plasmonic activity, it is necessary to use silver (Ag) probes due to their plasmonic range in the visible region. However, the Ag probe fabrication process remains challenging and is not yet standardized in practice, leading to inconsistent enhancements even for two similar types of tips prepared consecutively. In this work, we demonstrate an alternative way to reuse and recycle a plasmonic tip for distinct molecular systems inside an ultrahigh vacuum (UHV). We provide evidence of the ability to recycle tips without compromising the TERS experimental results. A long-term preservation (>2 months) of plasmonically active probes inside UHV is demonstrated.