Pulsed contact resonance for atomic force microscopy nanomechanical measurements

We demonstrate an improved technique for nanomechanical imaging in atomic force microscopy. By merging the sensitivity to contact stiffness inherent to contact resonance (CR) spectroscopy with the delicate nature and potential for adhesion data of pulsed-force mode, we address major shortcomings of both techniques. Fast CR data are recorded during each pulsed cycle by driving the sample at two frequencies near the CR frequency and modeling the contact as a harmonic oscillator. The technique provides nanomechanical parameters including frequency, quality factor, and adhesion force. Compared to continuous contact, the technique should reduce damage and support more complex analysis models. [doi:10.1063/1.3680212]