Multiplexed Gas Sensor Based on Heterogeneous Metal Oxide Nanomaterial Array Enabled by Localized Liquid-Phase Reaction

A novel method for the selective and localized synthesis of nanomaterials and their in situ integration based on serial combination of localized liquid-phase reaction has been developed for the fabrication of heterogeneous nanomaterial array. This method provides simple, fast and cost-effective fabrication process by using well-controlled thermal energy and therefore solves the challenging problems of assembly and integration of heterogeneous nanomaterial array in functional microelectronic devices. We have fabricated a parallel array of TiO2 nanotubes, CuO nanospikes, and ZnO nanowires, which exhibited adequate gas sensing response. Furthermore, we could approximately determine individual gas concentrations in a mixture gas consisting of 0–2 ppm of NO2 and 0–800 ppm of CO gas species by analyzing multiple data from an array of heterogeneous sensing nanomaterials.