Gas sensing enhancement of aluminum-doped ZnO nanovase structure with many gas facile diffusivity paths

Al-doped ZnO nanovase structures were synthesized by thermal evaporation method with a fast temperature rise speed. It was found that there were a good amount of nanovase structures with a large aperture on the top of it and many short nanorods grew from their surface to generate many holes or channels enough for gas to quickly diffuse from surface to the inside of nanovase. Gas sensors were fabricated using the Al-doped ZnO nanostructures to examine the responses to 500 ppm C2H5OH, CO, NH3, and CH4 gases. The Al-doped ZnO nanovases exhibited a better response and selectivity toward ethanol as high as 34.1 at 300 degrees C. These results showed that Al-doped ZnO nanovases are highly promising for ethanol sensor applications, as the gas diffusion and mass transportation in sensing materials are significantly enhanced by their unique structures. (C) 2012 Elsevier B.V. All rights reserved.