Ultrathin Atomically Flat Gold Film for Scanning Tunneling Microscopy and Single-Particle Fluorescence Spectroscopy.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Simultaneous optical and electronic characterization of nanoparticles is crucial for understanding their properties.
• Existing methods often require specialized substrates or complex fabrication processes.
• Template-stripped gold films offer a promising route for high-quality nanoscale surface preparation.

Purpose of the Study:

• To establish the smoothness and thickness limits of template-stripped gold films for advanced microscopy.
• To evaluate the suitability of these gold films for simultaneous single-particle fluorescence and scanning tunneling microscopy.
• To demonstrate the capability of characterizing nanoscale materials like carbon dots on these gold films.

Main Methods:

• Fabrication of template-stripped gold films via room-temperature deposition (1-200 pm/s) on mica, fused silica, silicon, and quartz.
• Characterization of gold film properties: thickness, absorbance, and root-mean-square roughness.
• Assessment of single-particle imaging using atomic force microscopy (AFM), scanning tunneling microscopy (STM), and confocal microscopy.

Main Results:

• Achieved transparent conductive gold films with thickness as low as 9 nm and root-mean-square roughness of 80 pm (100x100 nm^2).
• Successfully resolved 1.0 nm height carbon dots using AFM and STM.
• Demonstrated single-particle fluorescence blinking measurements of carbon dots via confocal microscopy.

Conclusions:

• Template-stripped gold films provide an accessible, high-performance substrate for combined optical and electronic nanoscale characterization.
• The developed protocol enables batch fabrication of substrates suitable for advanced single-particle imaging techniques.
• This approach facilitates comprehensive analysis of nanomaterials by integrating multiple microscopy modalities on a single sample.