Multimodal microscopy using 'half and half' contact mode and ultrasonic force microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Characterizing multifunctional nanostructured materials demands techniques for simultaneous multi-property mapping at the nanoscale.
• Existing methods often lack the resolution or multi-modal capability required for complex nanomaterials.

Purpose of the Study:

• To develop and demonstrate a multimodal atomic force microscopy (AFM) approach for simultaneous nanoscale property mapping.
• To combine nanomechanical, friction, and conductivity measurements for comprehensive material analysis.

Main Methods:

• Utilized a 'half and half' approach, rapidly alternating between ultrasonic force microscopy (UFM) and contact mode scanning within AFM.
• Acquired simultaneous contact mode (friction, conductivity) and UFM (nanomechanical) data at each pixel for high-resolution imaging.
• Applied the technique to graphene on copper, single-walled carbon nanotubes (SWNTs) on silicon oxide, and graphene epoxy composites.

Main Results:

• Successfully demonstrated simultaneous mapping of nanomechanical, friction, and conductivity properties at the nanoscale.
• The 'half and half' method allowed friction force measurement without topographical cross-talk.
• Ultrasonic force microscopy's superlubricity enabled standard contact mode imaging of delicate samples like SWNTs.

Conclusions:

• The developed multimodal AFM technique is effective for characterizing complex nanostructured materials.
• This approach offers significant advantages for analyzing delicate nanomaterials and composite systems.
• It provides a powerful tool for advancing the design and fabrication of multifunctional nanostructured materials.