Quantitative comparison of closed-loop and dual harmonic Kelvin probe force microscopy techniques

Area of Science:

• Surface science
• Nanotechnology
• Scanning probe microscopy

Background:

• Kelvin probe force microscopy (KPFM) is crucial for nanoscale surface potential mapping.
• Traditional KPFM uses a closed-loop feedback system to nullify electrostatic forces.
• Open-loop KPFM techniques, like DH-KPFM, present implementation and artifact advantages.

Purpose of the Study:

• Directly compare closed-loop KPFM with open-loop DH-KPFM.
• Evaluate bandwidth and sensitivity to instrumentation artifacts.
• Introduce a novel correction for traditional KPFM to improve agreement with open-loop methods.

Main Methods:

• Comparative analysis of KPFM techniques.
• Implementation of a "setpoint correction" for closed-loop KPFM.
• Assessment of bandwidth and artifact sensitivity.

Main Results:

• DH-KPFM demonstrates simpler implementation and reduced artifact sensitivity.
• The "setpoint correction" enables agreement between open-loop and closed-loop KPFM within 1%.
• Direct comparison highlights differences in bandwidth and artifact susceptibility.

Conclusions:

• Quantitative validation of DH-KPFM is essential for wider adoption.
• Open-loop KPFM techniques offer significant benefits, including operation in liquid environments.
• The developed correction method bridges the gap between open-loop and closed-loop KPFM.