Gas sensitive properties of ZnO nanorods formed on silicon and glass substrates

Abstract

Nanostructured materials based on zinc oxide are being intensively studied, since such materials are used to create energy harvesters, gas sensors, and solar cells. Arrays of nanoscale ZnO nanorods are synthesized on silicon and glass substrates by the hydrothermal method. The formed ZnO nanorods with predominantly vertical orientation have an average transverse size of about 30–40 nm and a length of 500–600 nm. For electrical contact, V-Cu-Ni metallization was deposited over ZnO nanorods. The work investigated the gas-sensitive and electrophysical properties of the formed sensitive elements with respect to carbon monoxide (CO). It is shown that the sensor element based on ZnO nanorods on glass has a 30% higher sensitivity and lower (10 ppm) sensitivity limit than similar structures, but formed on silicon. Peculiarities of the response of gas sensors based on ZnO arrays of nanorods were determined, including the effect of temperature, the rate of gas flow, and the effect of the substrate. A method for measuring gas-sensitive properties has been developed. It is shown that sensors based on such sensor structures can be used as energy-efficient gas sensors, as well as detectors in early fire detection systems, robotic sensor systems, and other modern technologies.