Graphene resonators for mass sensing applications

Abstract

Graphene’s exceptional physical and mechanical properties make it an excellent nanomaterial for MEMS/NEMS devices with wide reaching applications. This thesis explores graphene as a nanomaterial, its use in mass sensing applications and the suitability of existing theoretical models to describe its behaviour as a rectangular resonator. Several local and nonlocal continuum models have been proposed in literature for the vibration analysis of graphene resonators. But with very little experimental data to validate these theoretical models, most of the solutions employed to solve these models compare their results with results from other theoretical models, leading to doubts about their validity and accuracy. In addition to providing a guide for determining the suitable theoretical model for different sized rectangular graphene resonators, this work establishes that a small-scale parameter 𝑒0𝑎 of any value between 0 and 2 needs to be incorporated in any local continuum modelled applied to micro-sized graphene sheets to avoid overestimation of the frequency of the sheets. A fabrication route for NEMS and MEMS devices with rectangular graphene resonators up to 32 𝜇𝑚 by 7 𝜇𝑚 is also developed with the provision for magnetomotive actuation via Lorentz force with possible capacitive readout capabilities. This is important as the use of graphene in MEMS/NEMS is being hurriedly transitioned from the Research space to the marketplace.