Angstrom-Resolved Interfacial Structure in Buried Organic-Inorganic Junctions

Area of Science:

• Materials Science
• Surface Science
• Spectroscopy

Background:

• Charge transport at interfaces is critical for many physical and chemical processes.
• Understanding buried interfaces is challenging due to limited surface sensitivity of conventional techniques.

Purpose of the Study:

• To report the first soft x-ray second harmonic generation (SXR SHG) spectrum of a buried boron-Parylene N interface.
• To demonstrate the high interfacial sensitivity of SXR SHG for buried interfaces.

Main Methods:

• Soft x-ray second harmonic generation (SXR SHG) spectroscopy.
• Electronic structure calculations.

Main Results:

• SXR SHG spectra exhibit distinct features not present in x-ray absorption spectra.
• Extraordinary interfacial sensitivity of SXR SHG was demonstrated.
• Electronic structure calculations determined a boron-organic separation distance of 1.9 Å.
• Small changes (<1 Å) in separation distance lead to detectable SXR SHG spectral shifts (hundreds of meV).

Conclusions:

• SXR SHG is a powerful, highly sensitive probe for buried interfaces.
• The technique can resolve subtle structural changes at interfaces.
• This method opens new avenues for characterizing interfacial phenomena in complex systems.