Measurement of electrostatic tip-sample interactions by time-domain Kelvin probe force microscopy
Christian Ritz1, Tino Wagner1,2, Andreas Stemmer1
1Nanotechnology Group, ETH Zürich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
Beilstein Journal of Nanotechnology
|June 30, 2020
Summary
This study presents a new Kelvin probe force microscopy method to accurately measure surface potential. It overcomes limitations of traditional techniques by compensating for bias modulation, enabling more reliable electrostatic and topographic measurements.
Area of Science:
- Surface science
- Scanning probe microscopy
- Electrostatics
Background:
- Kelvin probe force microscopy (KPFM) quantifies surface electrostatic potential using bias modulation.
- Conventional KPFM uses lock-in detection but can suffer from uncompensated static contributions causing topographic errors.
Purpose of the Study:
- To develop an alternative KPFM approach for accurate surface potential measurement.
- To compensate for electrostatic influences, including bias modulation artifacts.
Main Methods:
- Utilizes frequency-modulated atomic force microscopy (FM-AFM).
- Operates directly on the frequency-shift signal to estimate electrostatic influence from voltage modulation.
- Continuously measures surface potential and capacitance gradient.
Main Results:
- Demonstrates a method to find surface potential without lock-in detection.
- Enables continuous measurement of surface potential, capacitance gradient, and topography-induced frequency shift.
- Compensates for all electrostatic influences, including bias modulation effects.
Conclusions:
- The new method offers improved accuracy and reliability in KPFM measurements.
- It overcomes limitations of conventional KPFM, particularly regarding topographic height errors.
- Paves the way for more precise electrostatic and topographic characterization of surfaces.
