Improved Selectivity and Sensitivity of Gas Sensing Using a 3D Reduced Graphene Oxide Hydrogel with an Integrated Microheater

Abstract

Low-cost, one-step, and hydrothermal synthesized 3D reduced graphene oxide hydrogel (RGOH) is exploited to fabricate a high performance NO<sub>2</sub> and NH<sub>3</sub> sensor with an integrated microheater. The sensor can experimentally detect NO<sub>2</sub> and NH<sub>3</sub> at low concentrations of 200 ppb and 20 ppm, respectively, at room temperature. In addition to accelerating the signal recovery rate by elevating the local silicon substrate temperature, the microheater is exploited for the first time to improve the selectivity of NO<sub>2</sub> sensing. Specifically, the sensor response from NH<sub>3</sub> can be effectively suppressed by a locally increased temperature, while the sensitivity of detecting NO<sub>2</sub> is not significantly affected. This leads to good discrimination between NO<sub>2</sub> and NH<sub>3</sub>. This strategy paves a new avenue to improve the selectivity of gas sensing by using the microheater to raise substrate temperature

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