Multi-modal graphene polymer interface characterization platform for vaporizable electronics

Characterization of physical and chemical properties of organic thin films such as polycarbonates is essential for their application-specific design. In this paper, we report a novel micromechanical resonant membrane platform with both graphene resistivity and mass-dependent frequency sensing to measure the thermal response, vaporization, and subsequent mass change of thin-film analytes deposited on top of the membrane. Graphene transferred on silicon nitride (Si_xN_y) is below the analyte thin film, and the graphene resistance changes due to dangling bond interactions between the analyte film and graphene surface. At the same time, the resonance frequency of the analyte film/graphene/Si_xN_y composite membrane changes with variations in temperature, mechanical properties, mass and elasticity of the analyte film. This device provides a bi-modal characterization of the organic thin film, both in the electrical and mechanical domain, which allows one to identify and optimize the organic film formulation. As an example, we demonstrate differentiating formulations of a polymer blend to realize low degradation temperature, which is critical for vaporizable electronics enabling low-power transience.