Signal reversal in Kelvin-probe force microscopy
P Mesquida1, D Kohl1, G Schitter1
1Automation and Control Institute (ACIN), TU Wien, Gusshausstrasse 27-29, A-1040 Vienna, Austria.
The Review of Scientific Instruments
|November 30, 2019
Summary
Kelvin-probe force microscopy (KPFM) can yield false electrical surface potential readings due to hardware cross talk. This study details an undetectable artifact and offers simple solutions for accurate KPFM measurements.
Area of Science:
- Surface science
- Scanning probe microscopy
- Electrical characterization
Background:
- Kelvin-probe force microscopy (KPFM) is a key technique for mapping sample surface potential.
- Signal cross talk from inadequate hardware or electronics can compromise KPFM accuracy.
- Existing diagnostic methods may fail to detect certain critical cross talk artifacts.
Purpose of the Study:
- To identify and characterize a specific, hard-to-detect cross talk artifact in KPFM.
- To demonstrate how this artifact can invert the measured surface potential scale.
- To propose practical methods for artifact detection and mitigation in KPFM.
Main Methods:
- Experimental KPFM measurements on an electrically homogeneous sample.
- Analysis of signal characteristics to identify cross talk.
- Development of a detection protocol and simple hardware/electronic remedies.
Main Results:
- Demonstration of cross talk artifacts manifesting as noise, reduced resolution, or offsets.
- Crucially, identification of an artifact that inverts the signal scale and evades standard diagnostics.
- Validation of a detection method and proposed remedies using experimental data.
Conclusions:
- Inadequate KPFM design can introduce undetectable artifacts, leading to erroneous surface potential measurements.
- A novel detection method and straightforward remedies are presented to ensure KPFM data integrity.
- These solutions are accessible for most research and industrial KPFM laboratories.
