Deep Electrode and Parylene E-Based Capacitive VOC Detector for Micro Gas Chromatograph Application

This paper presents a capacitive volatile organic compound (VOC) detector with parylene E-coated high-aspect-ratio (HAR) deep electrodes, which opens up a new design framework for high-sensitivity and low limit-of-detection detectors with low power consumption. From evaluations of the VOC sensing performance in steady-state flow, the sensitivity of the HAR detector achieves 48 times higher than that of the planar type with the same width and gap. In GC experiments, the present HAR detector captures well-resolved peaks of VOC mixtures, validating its use as a gas chromatography detector. The sensitivity of the HAR detector against toluene vapor is estimated to be 0.073 fF.s/ppm, which is over 5 times of that of the state-of-the-art PDMS planar detector.