Experimental setup for measuring the dispersion forces by the adhered cantilever method

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Dispersion forces are critical in micro/nanoelectromechanical devices (MEMS/NEMS).
• Existing measurement methods for short-range forces (<50 nm) face pull-in instability.
• The adhered cantilever method offers a stable alternative for measuring forces at small separations.

Purpose of the Study:

• To present an instrument and data processing method for measuring dispersion forces and adhesion energies.
• To reconstruct the shape of an adhered elastic beam with high accuracy.
• To enable measurements of forces between rough surfaces in unloaded contact.

Main Methods:

• Utilized an adhered cantilever with specific dimensions (12 mm long, 200 μm wide, 10 μm thick).
• Employed interferometric methods based on differential interference-contrast for shape measurement.
• Developed a data processing algorithm for beam shape reconstruction with 1 nm accuracy over 5000 nm.

Main Results:

• Achieved accurate reconstruction of the adhered cantilever's shape.
• Demonstrated measurement capability at separations relevant to dispersion force contributions (30-100 nm).
• The instrument achieved a noise level of 0.33 nm with 0.1 μm scanning step.

Conclusions:

• The developed instrument and algorithm effectively measure dispersion forces and adhesion energies.
• The adhered cantilever method overcomes pull-in instability for short-range force measurements.
• This technique is suitable for analyzing unloaded contact between rough surfaces.