Ultra-Sensitive Duffing Behavior of a Microcantilever

We investigate the properties of an electrostatically driven microcantilever exhibiting duffing-like behavior using harmonic detection of resonance. Its potential use as a highly sensitive sensing platform is discussed. We find high sensitivity of this duffing system near its bistability point in a gaseous environment. The response of the higher harmonics of the measured charge on the cantilever induced by an ac voltage that drives the counter electrode is investigated. In particular, we follow the duffing behavior at the higher harmonics (up to the sixth harmonic) as a function of gap distance between the cantilever and counter electrode. To our knowledge, this work represents the first experimental demonstration of sensing a pressure change using the duffing behavior.