A Zinc Oxide nanowire-based Sensing Platform for Carbon Dioxide Detection

ZnO nanowires have been a focus of intense research in recent decade. The superior physical and chemical properties demonstrated by these nanostructures stem from their unique morphology and surface structures. High surface-to-volume ratio concomitant with their semiconducting yet inert nature makes them a high potential material for developing varied spectrum of devices. Specifically, their favorable surface chemistry makes them an ideal candidate for developing highly sensitive chemical gas sensor. In this work, ZnO nanowires have been utilized in array morphology to develop a sensing device and platform with back-end electronics for remotely monitoring and logging real-time carbon dioxide concentration. Vertically oriented, hierarchical nanowire arrays were grown on insulating sapphire substrate. The extremities of the nanowire grown substrates were contacted with colloidal silver to form electrodes. The I-V characteristics of the sensing device were determined through a semiconductor parameter analyzer and the data obtained was used to calibrate the electronics needed for the sensing platform. The overall topology of the sensing platform comprises a nanowire-based sensing device that interfaces with an analog sensing board that processes data in real-time and transmits it over a wireless protocol. The receiver end is equipped with electronics to decode the digital packets and a GUI to display obtained data in real-time. The sensor chip is operated at 150C to provide the necessary activation energy to the oxygen surface sites on ZnO nanowires to take part in sensing operation for attracting and detecting carbon dioxide molecules.