Characterization of ZnO Nanorods and SnO2-CuO Thin Film for CO Gas Sensing

In this study, ZnO nanorods and SnO2-CuO heterogeneous oxide were grown on membrane-type gas sensor platforms and the sensing characteristics for carbon monoxide (CO) were studied. Diaphragm-type gas sensor platforms with built-in Pt micro-heaters were made using a conventional bulk micromachining method. ZnO nanorods were grown from ZnO seed layers using the hydrothermal method, and the average diameter and length of the nanorods were adjusted by changing the concentration of the precursor. Thereafter, SnO2-CuO heterogeneous oxide thin films were grown from evaporated Sn and Cu thin films. The average diameters of the ZnO nanorods obtained by changing the concentration of the precursor were between 30 and 200 nm and the ZnO nanorods showed a sensitivity value of 21% at a working temperature of 350 degrees C and a carbon monoxide concentration of 100 ppm. The SnO2-CuO heterogeneous oxide thin films showed a sensitivity value of 18% at a working temperature of 200 degrees C and a carbon monoxide concentration of 100 ppm.