Improvement of KFM performance by intermittent bias application method and by sampling detection of cantilever...

We have proposed an intermittent bias application method as well as a sampling detection method of cantilever deflection in Kelvin probe force microscopy (KFM) to improve its performances for surface potential measurements. In the former method, spiky biases, instead of the bias in a sinusoidal waveform normally used in KFM, are intermittently applied to generate electrostatic force at exact moments when the tip approaches the closest position to a sample surface. The latter one, on the other hand, realizes very sensitive detection of the electrostatic force, which is preferable in KFM. Both the dependence of the electrostatic force on the dc offset bias and the observed potential images clearly indicate that these two methods are very effective to improve the KFM performance.