Mechanics of Surface Enhanced Microcantilever Sensors

Abstract

Surface stress is widely used to characterize the adsorption and surface morphology effects on the mechanical response of nanomaterials and nanodevices. In this paper, we will summarize the authors’ recent studies of the impacts of surface stress on the static and dynamic properties of microcantilever sensors with topological surfaces. We first analyze the connections between the surface stress at the continuum level and the adsorbate interactions (e.g., the van der Waals and Coulomb interactions) at the molecule level. Then, two strategies of introducing porous films and rough surfaces to improve the sensitivities of surface enhanced microcantilver sensors for the bending and resonance frequency shift are presented. The bending and resonance frequency shift of these novel microcantilever sensors with the effects of the eigenstrain, the surface stress and the adsorption mass are analyzed. In addition, the relationship between the surface stress and surface corrugation is obtained. Finally, we show that both nano-porous films and rough surfaces with optimized topology can dramatically enhance the sensitivities of these novel microcantilever sensors.