Note: Quantitative (artifact-free) surface potential measurements using Kelvin force microscopy

The measurement of local surface potentials by Kelvin force microscopy (KFM) can be sensitive to external perturbations which lead to artifacts such as strong dependences of experimental results (typically in a similar to 1 V range) with KFM internal parameters (cantilever excitation frequency and/or the projection phase of the KFM feedback-loop). We analyze and demonstrate a correction of such effects on a KFM implementation in ambient air. Artifact-free KFM measurements, i.e., truly quantitative surface potential measurements, are obtained with a similar to 30 mV accuracy. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3516046]