Fabrication and Ethanol Sensing Characterization of Tin Oxide Nanorods Prepared by Glancing Angle Deposition Technique

In this work, the nanorod structure of Tin oxide (SnO2) prepared by glancing angle deposition (GLAD) technique with different O2 flow rate from 12 to 48 sccm. The surface and Crystal structure of SnO2 thin films were characterized by scanning electron microscopy (SEM), X-raydiffraction (XRD) and tested toward ethanol gas sensing. Structural characterization showed that the morphological of all SnO2 thin films prepared with different O2 flow rates consists of columnar nanorod structures and the nanorod size which are likely to decrease as the O2 flow rate increases. As the O2 flow rate increases from 12 to 48 sccm, the crystal structure of SnO2 nanorods changes from amorphous to crystalline and the crystallinity is improved by the increase of the O2 flow rate. Gas sensing performances of SnO2 nanorods have been characterized toward ethanol sensing. It was found that SnO2 nanorods exhibit n-type conductivity with decreased resistance when exposed to ethanol, which is reducing gas. In addition, sensitivity to ethanol tend to improve as O2 flow rate increases. Furthermore, the SnO2 nanorods prepared at O2 flow rates 48 sccm are detecting ethanol gas at concentrations lower than 50 ppm at operating temperature 250 °C.