Porous Carbon Nanotube Ring Resonators for Gas Sensing Application

Using the carbon nanotube templated micro-fabrication (CNT-M) method we have formed and characterized porous micro-mechanical ring resonators for gas sensing applications. The tunable porosity of the CNT structures lends itself to high surface area to volume ratios. In the resonator, a high surface area to mass ratio coupled with a high quality factor (Q) can enable detection of gasses at very low concentrations. The gas concentration detection limit is proportional to the inverse of the Q of the resonator. Building on previous work with micro-cantilevers, here we present results of in-plane ring resonators designed to reduce clamping and thermoelastic losses. This in-plane mode has the added advantage of being less sensitive to manufacturing variations in the height of the resonator. We present our work characterizing the gas and time response of these resonators.