ZnO nanowires on the a-, c- and m-plane oriented 4H-SiC substrates were grown by using a high temperature tube furnace, Ti/Au electrodes were deposited on ZnO nanowires and a-, c- and m-plane 4H-SiC substrates, respectively. The shape and density of the ZnO nanowires were inestigated by field emission scanning electron microscope. It was found that the growth direction of nanowires depends strongly on growth parameters such as growth temperature and pressure. In this work, The sensitivity of nanowires formed a-, c- and m-plane oriented 4H-SiC gas sensor was measured at 300℃ with CO gas concentration of 80%. The nanowires grown on a-plane oriented 4H-SiC show improved performance than those on c- and m-plane oriented 4H-SiC due to the increased density of nanowire on a plane 4H-SiC.

ZnO thin films were deposited on p-type 4H-SiC substrate by pulsed laser deposition. ZnO nanowires were formed on p-type 4H-SiC substrate by furnace. Ti/Au electrodes were deposited on ZnO thin film/SiC and ZnO nanowire/SiC structures, respectively. Structural and crystallographical properties of the fabricated ZnO thin film/SiC and ZnO nanowire/SiC structures were investigated by field emission scanning electron microscope and X-ray diffraction. In this work, resistance and sensitivity of ZnO thin film/SiC gas sensor and ZnO nanowire/SiC gas sensor were measured at 300℃ with various CO gas concentrations (0%, 90%, 70%, and 50%). Resistance of gas sensor decreases at CO gas atmosphere. Sensitivity of ZnO nanowire/SiC gas sensor is twice as big as sensitivity of ZnO thin film/SiC gas sensor.