Optical scanning tunneling microscopy based chemical imaging and spectroscopy

Area of Science:

• Surface Science
• Molecular Physics
• Chemical Physics

Background:

• Single-molecule investigations require ultimate spatial and temporal resolution.
• Optical processes and scanning tunneling microscopy (STM) offer complementary probes.

Purpose of the Study:

• To review methods coupling optical imaging/spectroscopy with STM.
• To highlight insights into molecular adsorbates, assemblies, and 2D materials.
• To enable fundamental chemistry studies at the spatial and temporal limit.

Main Methods:

• Tip-enhanced Raman spectroscopy (TERS) for vibrational fingerprints.
• STM-induced luminescence for organic adsorbates and energy transfer.
• Probing light-induced photophysical and photochemical transformations with STM.

Main Results:

• Subnanoscale resolution achieved for individual molecules and materials.
• Detailed understanding of energy and charge transfer processes.
• Insights into molecular dynamics under optical excitation.

Conclusions:

• STM-optical coupling provides unprecedented insights into molecular-level phenomena.
• Enables fundamental studies of chemistry and physics at the ultimate limit.
• Opens new avenues for nanoscale chemical and physical investigations.