Electrical Measurements with ScanAsyst and PeakForce QNM?

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Chunzeng Li replied on Tue, Mar 2 2010 2:22 AM

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The short answer is yes. Electric force microscopy (EFM) and Kelvin probe force microscopy (KPFM) can be either done in a two-pass lift-mode or in a single-pass dual ac frequency mode.  Both EFM/KPFM can be done with Peakfroce tapping mode in the two-pass fashion, with the 1st pass using Peakforce tapping for topography, and 2nd pass collecting EFM/SKPFM signal at the resonant frequency of the cantilever. There is an inherent difficulty with the one-pass detection scheme for Peakforce tapping. The one-pass technique requires superimposing a 2nd ac drive typically at the 1st or 2nd eignefrequency of cantilever. The problem is oscillation at these frequencies will be excited each time the tip snaps off the surface, making it hard to separate from oscillation caused by electric forces.