Transfer and inkjet printing of gold thin film and graphene oxide nanoparticles for micro-oscillators

This study presents the results of micro-oscillator fabrication using the transfer printing (TP) of gold (Au) thin films and inkjet printing of graphene oxide (GO) nanoparticles. The Au thin films are formed into a double -supported microbeam to function as a micro-oscillator on a polymer substrate. The Au microbeams have a thickness of 300 nm and a length of 250 or 300 mu m. To improve adhesion strength between the substrate and the Au thin film, the Au thin film is transferred and printed onto a substrate pre-coated with a 30-nm-thick Au surface via atomic diffusion bonding. Furthermore, GO nanoparticles are deposited on the transfer-printed Au thin film and the convex part of the stamp using inkjet printing to enhance the mechanical properties of the micro -oscillator. The former deposition forms a double-layered beam of Au and GO. The Au/GO/Au-layered microbeam is fabricated on a pre-structured substrate by TP after another Au thin film is then deposited on this GO/Au surface. These micro-oscillators can be driven by electrostatic force at less than 10 kHz with 90-210 V of applied voltage, while the deflection of the micro-oscillator is measured by a laser displacement meter. The Au micro-oscillators have a damping ratio of 0.166, and a resonance frequency of 0.28 kHz. This resonance frequency is smaller than that estimated by finite element method analysis. This difference in resonance frequency is attributed to the Young's modulus of the Au thin film and structural defects due to van der Waal bonding. The modulus of the laminated thin film of Au and GO nanoparticles is higher than that of the Au thin film.