High spatial resolution Kelvin probe force microscopy with coaxial probes.
Keith A Brown1, Kevin J Satzinger, Robert M Westervelt
1School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
Nanotechnology
|February 29, 2012
Summary
Researchers developed novel coaxial AFM probes to enhance Kelvin probe force microscopy (KPFM) spatial resolution. These shielded probes confine electrostatic interactions, improving contact potential difference (CPD) measurements by fivefold.
Area of Science:
- Surface science
- Nanotechnology
- Scanning probe microscopy
Background:
- Kelvin probe force microscopy (KPFM) measures local contact potential difference (CPD) using electrostatic forces.
- KPFM's spatial resolution is limited by the long-range electrostatic interactions of the AFM probe.
- Existing KPFM techniques face challenges in achieving high spatial resolution due to probe design.
Purpose of the Study:
- To improve the spatial resolution of KPFM measurements.
- To overcome the limitations imposed by the long-range electrostatic interactions in conventional AFM probes.
- To develop a new probe design for enhanced electrostatic force microscopy.
Main Methods:
- Development of coaxial AFM probes with a shielded cantilever and conical tip.
- Implementation of a technique to measure true CPD with the shielded probe.
- Comparison of spatial resolution between shielded and unshielded probes.
Main Results:
- Coaxial probes successfully confine tip-sample electrostatic interactions to the probe's apex.
- A fivefold improvement in spatial resolution was observed compared to unshielded probes.
- Measured CPD behavior aligns with electrostatic models for the developed probes.
Conclusions:
- Coaxial AFM probes offer significantly enhanced spatial resolution for KPFM.
- The field confinement design is beneficial for KPFM and other electrostatic force microscopy variants.
- This innovation advances high-resolution surface potential mapping capabilities.
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