Intermodulation Electrostatic Force Microscopy (ImEFM)

ImEFM is more sensitive than standard Kelvin Probe Force Microscopy (KPFM). ImEFM uses resonance to enhance sensitivity, and it works very close to the surface without lift-mode, thereby giving higher resolution. You can scan faster than standard KPFM with the same signal-to-noise ratio. ImEFM works without voltage feedback so you are free to apply an arbitrary DC voltage to the tip and study how the electrostatic force responds to this 'gating' potential.

Read more in the software manual

ImEFM on graphene showing surface potential in Volts.  Monolayer graphene is lightest, bilayer intermediate and trilayer darkest.  Scan size is 4um.  The intermodulation spectrum is shown for the pixel marked with an X on the image.

ImEFM in publications

Intermodulation electrostatic force microscopy for imaging surface photo-voltage
Riccardo Borgani, Daniel Forchheimer, Jonas Bergqvist, Per-Anders Thorén, Olle Inganäs, and David B. Haviland
Applied Physics Letters 105, 143113 (2014)
Local Charge Injection and Extraction on Surface-Modified Al2O3 Nanoparticles in LDPE
R. Borgani, L. K. H. Pallon, M. S. Hedenqvist, U. W. Gedde and D. B. Haviland
Nano Lett. 2016, 16, 5934−5937