Tip-enhanced Raman spectroscopy (TERS) is a very powerful variant of surface-enhanced Raman spectroscopy (SERS). In a sense, TERS overcomes most of the drawbacks of SERS but keeps its advantages, such as its high sensitivity. TERS offers the additional advantages of high spatial resolution, much beyond the Abbe limit, and the possibility to correlate TER and other scanning probe microscope images, i.e., to correlate topographic and chemical data. TERS finds application in a number of fields, such as surface science, material science, and biology. Single-molecule TERS has been observed even for TERS enhancements of “only” 10⁶–10⁷. In this review, TERS enhancements are discussed in some detail, including a condensed overview of measured contrasts and estimated total enhancements. Finally, recent developments for TERS under ultrahigh vacuum conditions are presented, including TERS on a C₆₀ island with a diameter of a few tens of nanometers, deposited on a smooth Au(111) surface.

The mechanical response of ultrathin NaCl crystallites of nanometer dimensions upon manipulation with the tip of a scanning tunneling microscope (STM) is investigated, expanding STM manipulation to various nanostructuring modes of inorganic materials as cutting, moving, and cracking. In the light of theoretical calculations, our results reveal that atomic-scale NaCl islands can behave elastically and follow a classical Hooke's law. When the elastic limit of the nanocrystallites is reached, the STM tip induces atomic dislocations and consequently the regime of plastic deformation is entered. Our methodology is paving the way to understand the mechanical behavior and properties of other nanoscale materials.