Membranes of organically cross-linked gold nanoparticles: Novel materials for MEMS/NEMS sensors and actuators

We report the application of freestanding membranes of cross-linked gold nanoparticles (GNPs) as functional materials in novel MEMS/NEMS sensors. GNP composite films are fabricated using a facile ink-based process and transferred onto lithograpically fabricated 3D microstructures, suitable to support and electronically address the resulting freestanding membranes. We show that 1,6-hexanedithiol cross-linked GNP membranes can be utilized both, as diaphragm and strain-sensitive transducer in highly sensitive gauge pressure sensors. Aside from this application, we demonstrate electrostatic actuation of such composite membranes and the fabrication of electrostatically driven GNP membrane drumhead resonators with resonance frequencies in the high kilohertz to low mega-hertz range. Further, these GNP membrane resonators are successfully employed as electromechanical chemical sensors for the detection of vapors and gases, using sorption-induced shifts of their fundamental resonance frequency as sensing signal.