High Resolution KPFM with Bruker PeakForce KPFM

KPFM (Kelvin Probe Force Microscopy – also known as Surface Potential Microscopy) is an AFM mode for measuring the work function of surfaces. It’s a commonly used analytical technique in corrosion research, photovoltaics, solar cells and surface analysis. Bruker’s PeakForce KPFM mode overcomes the common limitations of KPFM for higher resolution and greater sensitivity:

  • Accurate, repeatable and sensitive work function measurements
  • Highest spatial resolution and artefact-free potential contrast
  • Correlated quantitative nanomechanical property mapping

Blue Scientific is the official distributor for Bruker AFM in the Nordic region (Denmark, Iceland, Norway, Sweden and Finland). If you have any questions, please get in touch.

Bruker Atomic Force Microscopes

KPFM Application Note

 Contact us on +44 (0)1223 422 269 or info@blue-scientific.com


  

Nordic SPM Conference 2018

Join us for an SPM Conference on 10-11 October 2018, following Nanoscience Days at the University of Jyväskylä, Finland.

  • Talks from invited speakers
  • Hands-on sessions
  • Updates on technological developments

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Kelvin Probe Force Microscopy

Kelvin Probe Force Microscopy (KPFM) maps electrostatic potential on the surface of your sample, to give you information about:

  • Electronic structure
  • Doping level variations
  • Trapped charges
  • Chemical identity

This is useful in research into organic photovoltaics, silicon and wide band-gap semiconductors, as well as other applications.

High Resolution KPFM

Bruker’s PeakForce KPFM module enhances KPFM by combining it with their exclusive high resolution PeakForce Tapping technology, an AFM mode with unique scan algorithms and probe technology.

What is PeakForce Tapping?

This enables quantitative work function mapping at high spatial resolution. Sensitivity is greater, and without the usual artefacts from mechanical cross-talk.

  • Highest spatial resolution and artefact-free potential contrast
  • Accurate, repeatable and sensitive work function measurements
  • Correlated quantitative nanomechanical property mapping
  • Easy to use, with optimised results

PeakForce KPFM enables consistent measurement across different material types, with the most accurate probe-to-probe surface potential measurements.

It can also be combined with Bruker’s PeakForce Tapping QNM mode for simultaneous, correlated nanoscale topography, electrical and mechanical property mapping.

 Kelvin Probe Force Microscopy

Polymer blend of polystyrene (PS) and low-density-polyethylene (LDPE). 10µm scan. Height, potential and quantitative mechanical property maps of Young’s modulus, deformation and adhesion.

Limitations of Standard KPFM

Conventional KPFM has several limitations, when using both amplitude and frequency modulation detection:

  • Amplitude modulation (AM) lacks spatial resolution because of the cantilever’s contribution to the error signal.
  • Frequency modulation (FM) lacks sensitivity and suffer from mechanical cross-talk.

These limitations are a particular problem for certain samples and studies, such as nanoscale structures with variations in modulus or adhesion. Setting up parameters can also be complex, which limits the consistency of results.

Overcoming Limitations

To overcome these limitations, Bruker’s PeakForce KPFM mode gives you the high spatial resolution of FM detection, while avoiding the common issues. This delivers consistent, quantitative work function measurements. Their patented LiftMode eliminates mechanical cross-talk. Unique technology delivers high resolution topography with the low-k, high-Q cantilevers that are required for high sensitivity.

PeakForce KPFM is able to resolve and quantify nanoscale work function variations that would usually be extremely challenging with conventional techniques. You can also collect directly correlated, quantitative, nanomechanical data with PeakForce QNM (Quantitative Nanoscale Mechanical Characterisation) mode.

In the example below, nanoscale phase segregation is clearly resolved. The potential channel shows accurate work function differences for the nanoscale domain. Using conventional AM detection these would have been underestimated by at least a factor of two. The adhesion image shows very fine phase structure with strong adhesion differences, which would usually remain ambiguous. LiftMode has removed any contamination from the potential signal, that may have been caused by adhesion differences. Property channels were acquired simultaneously.

KPFM AFM

Quantitative work function measurements on a nanostructured Sn-Pb alloy (size: 4µm).

Complete KPFM Package

PeakForce KPFM includes all industry-standard KPFM implementations, together with a high-voltage mode. This enhances the potential range by a factor of >10, and gives you unmatched capabilities:

  • Image potential variations in complex materials
  • Study electronic structure in semiconductors
  • Map chemical distribution with work function variation
  • …and more

Easier to Use

Standard KPFM can be complex and tricky to set up. However, Bruker’s ScanAsyst mode features algorithms to automatically monitor image quality and adjust parameters for you, to give you the best results. This means that non-expert AFM users can achieve excellent quality results, and makes traditionally complex modes like KPFM much more accessible.

Instrumentation

PeakForce KPFM is available with these Atomic Force Microscopes from Bruker.

See the Dimension Icon and MultiMode at our Nordic SPM Conference on 10-11 October 2018 in Finland

Bruker Dimension FastScan AFM

Bruker Dimension FastScan Bio AFM

Bruker Dimension Icon AFM

Dimension FastScan

World’s fastest AFM

More info…

Dimension FastScan Bio

Biological AFM imaging

More info…

Dimension Icon

Flaxible AFM, also suitable for large samples

More info…

Bruker Dimension Icon-Raman

Bruker Multimode 8 AFM

Dimension Icon-Raman

Co-located AFM and Raman microscopy

More info…

MultiMode 8-HR

High resolution, small sample AFM

More info…

Further Information

More detailed information about KPFM, with technical diagrams and example results is available in this application note from Bruker:

Application Note

Blue Scientific is the official Nordic distributor for Bruker Nano Surfaces, and we’re available to answer all your questions and provide quotes. Please feel free to get in touch with any queries:

 Contact us on +44 (0)1223 422 269 or info@blue-scientific.com

Bruker Atomic Force Microscopes