Spatially Resolved Spectroscopic Characterization of Nanostructured Films by Hyperspectral Dark-Field Microscopy.

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Nanostructured films offer unique electrical, optical, and plasmonic properties crucial for advanced thin-film devices.
• In situ, nondestructive, and high-resolution characterization is vital for optimizing these devices.

Purpose of the Study:

• To develop and demonstrate a hyperspectral dark-field microscope (HSDFM) for advanced nanostructured film characterization.
• To investigate the plasmonic coupling, surface adsorption, and structural features of various nanostructured materials.

Main Methods:

• Construction of a laboratory-built HSDFM by integrating a hyperspectral imager with a commercial microscope.
• High-resolution spectral analysis (Δλ = 0.4 nm) with spatial resolution up to 45 nm × 45 nm.
• Investigation of gold nanoplate arrays, gold nanoparticle (GNP) sub-monolayers, titanium dioxide (TiO2) films, and molybdenum disulfide (MoS2) sheets.

Main Results:

• Identified lack of plasmonic coupling in gold nanoplate clusters due to large inter-plate gaps.
• Observed red-shifted plasmon resonance in aggregated GNPs indicating internal plasmonic interaction.
• Characterized inhomogeneous protein adsorption on TiO2 films and observed stepped boundaries of MoS2 sheets.
• Determined a minimum detectable thickness of 6.5 nm (10-layer MoS2 film) using HSDFM combined with atomic force microscopy.

Conclusions:

• The developed HSDFM is highly effective for in situ, nondestructive characterization of nanostructured films.
• HSDFM provides valuable insights into nanoscale optical and structural properties, essential for thin-film device development.
• The technique demonstrates broad applicability across diverse nanostructured materials.