EFFECT OF SURFACTANT ON THE MORPHOLOGY OF ZnO/Al:ZnO NANOSTRUCTURES AND THEIR ETHANOL SENSING APPLICATIONS AT ROOM TEMPERATURE

Zinc oxide (ZnO) and aluminum (Al) doped ZnO nanostructures with and without surfactant have been successfully prepared via sol-gel route. The effect of the surfactant glyoxalic acid and various concentration of Al on the structural property of ZnO was analyzed by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The morphology of the samples was recorded using field emission scanning electron microscopy. The uniform distribution of ZnO nanostructures with hexagonal facets is facilitated by the surfactant and the grain growth is further inhibited by the increase in concentration of Al. The ethanol (0-300 ppm) sensing characteristics of the as-prepared samples were systematically investigated at room temperature. Surfactant-assisted ZnO/Al: ZnO nanostructures show higher sensitivity of 94% at room temperature than ZnO/Al: ZnO nanostructures without surfactant. Faster response at 68 s and recovery at 50 s is also achieved by the samples. The surfactant-assisted ZnO nanostructures exhibit sharp selective detection towards ethanol when compared to the samples without surfactant. The enhanced ethanol sensing property may be ascribed to the larger surface area which is due to uniform and smaller crystallite size of the surfactant-assisted sample.