Coupling Resonant Micro and Nanocantilevers to Improve Mass Responsivity by Detectability Product

The advantage of combining a stiff microcantilever coupled mechanically to a soft nano cantilever in terms of mass responsivity and readout capacitive detectability is presented. The large spring constant and coupling capacitance values of the microcantilever allow maximizing the detectability quantified in terms of motional resistance. The small effective mass of the nanocantilever provide to the whole system with an optimized mass responsivity. A figure of merit that accounts for both characteristics, mass responsivity and detectability, is defined, calculated from FEM simulations and measured from mass detection experiments, in order to demonstrate that the combined system improve the performance of the individual components.