Design and optimization of a harmonic probe with step cross section in multifrequency atomic force microscopy

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Multifrequency atomic force microscopy (AFM) utilizes harmonic resonance frequencies to improve detection sensitivity.
• Existing harmonic probe designs have limitations in design flexibility and structural integrity.

Purpose of the Study:

• To propose and design a novel harmonic probe with a step cross-section for enhanced AFM sensitivity.
• To achieve tailored higher-order resonance frequencies that are integer multiples of the fundamental resonance frequency.

Main Methods:

• A harmonic probe with a step cross-section was designed with variable widths in the top and bottom steps.
• Structural optimization framework was employed for probe design.
• Focused ion beam milling was used for micromachining the optimally designed probe.

Main Results:

• The designed probe successfully achieved higher-order resonance frequencies as integer multiples of the fundamental frequency.
• Experimental measurements using AFM confirmed the resonance frequency assignment requirement.
• The new design offers improved design capability while maintaining structural integrity.

Conclusions:

• The proposed step cross-section harmonic probe significantly enhances AFM detection sensitivity.
• This design provides a versatile platform for advanced material property analysis.
• The findings pave the way for more sensitive and precise AFM applications.