A highly selective chemical sensor array based on nanowire/nanostructure for gas identification

Real-time detection and identification of multiple gases based on a single-nanowire sensor array have been investigated. We present the fabrication, characterization, and sensing performance of a single-nanowire array consisting of four different materials from three categories, which are metal (palladium), conducting polymer (polypyrrole and polyaniline), and semiconductor (zinc oxide), on a chip via a site-specific electrochemical deposition process. The presented nanowire array on a single chip has been used to detect and identify four target gases including hydrogen, methanol, carbon monoxide, and nitrogen dioxide. Each single nanowire shows an excellent sensitivity at room temperature, and a sub-ppm (parts per million) detection limit is achieved. The identification of these four targets has been successfully demonstrated with the help of principal component analysis. Our study shows that this single-nanowire sensor array is able to not only accurately distinguish four targets but also roughly estimate the target concentration, forming a basis for an electronic nose with far-reaching applications.