30 Dec 2016

Through a novel approach, we provide a method to decouple one of the major problems into KPFM/EFM advanced modes, the mechanical crosstalk. The idea is simple, we will use KPFM/EFM to acquire an image with the electrical information plus the mechanical crosstalk. Afterwards, a standard Bimodal AFM image is used to acquire the mechanical properties of the sample. Both images are then compared to see if electrostatic data can be used to interpret different electrostatic properties of the sample.
In order to compare both images, the exact same tip and parameters have to be employed. For instance, the following list of parameters have to be same for both modes: Amplitude of eigenmode 1, Amplitude of eigenmode 2, topography setpoint, scan speed and PID feedback for topography. With such parameters being the same, one can compare the Bimodal and KPFM/EFM information to realize if true electrostatic signal is obtained.

In our manuscript “Distinguishing between Mechanical and Electrostatic Interaction in Single Pass Multi Frequency Electrostatic Force Microscopy Measurements on a Molecular Material” published in the prestigious journal “Langmuir”, we provided the exact theoretical and experimental work that lead to the conclusion that mechanical crosstalk can really be decouple from electrostatic information.
Distinguishing between Mechanical and Electrostatic Interaction in Single Pass Multi Frequency Electrostatic Force Microscopy Measurements on a Molecular Material

Andres Gomez has a BSc in Physics, he is an Eng. in electronics and MSc in micro and nanoelectronics. He works in the SPM Laboratory in the Institut of Material Sciencie of Barcelona (ICMAB) in Barcelona, Spain. His mainly interests are the exploration of new techniques and characterization modes through the AFM technique. He is the inventor of a new Atomic Force Microscopy mode called Direct Piezoelectric Force Microscopy (DPFM), patent presented.

Image: Topography overlaid over the EFM Amplitude image (red) and bimodal AFM Amplitude (green). Under the topography image, it is possible to obtained different kind of information, however knowing the exact type of information is crucial to use KPFM technique in a reliable manner.