Synthesis of SnO2 Nanowires on Quartz and Silicon Substrates for Gas Sensors

Tin oxide nanowires (SnO2 NWs) were grown on quartz and silicon substrates via a modified chemical vapor deposition (CVD). Film of gold nanoparticle deposited on both types of substrates using the direct current DC-sputtering technique. The structure and morphology of the produced material were characterized by using atomic force microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible (UV-Vis) techniques. The XRD and SEM analysis confirmed the formation of tetragonal SnO2 NWs with a wire length of 10-20 mu m and a diameter of 40-100 nm. The UV-Vis spectrum shows a strong absorption peak in the UV and others in the visible regions. The bandgap was calculated for SnO2 NWs grown on a quartz substrate within the value of 3.2 eV. It is slightly lower than the bandgap value of bulk. The successfully synthesized SnO2 NWs via CVD with a large aspect ratio in the range of 250-200 was proved to be quite promising nanomaterials to use for sensor fabrication towards ethanol gas at room temperature. The high sensitivity of 2.7 at an ethanol gas concentration of 500 parts per million (ppm) was achieved. The proposed sensing mechanism of SnO2 NWs towards ethanol gas was also discussed.