Gas sensing properties of Y-doped ZnO nanosheets synthesized via combustion method

ZnO nanosheets doped with yttrium (Y) were synthesized via a solution combustion method using zinc nitrate and tartaric acid as raw materials. The scanning electron microscopy and X-ray powder diffraction were used to characterize ZnO nanosheets and the gas sensing properties of them were investigated. The results show that the as-synthesized ZnO nanosheets with diameters of 20-100 nm have a wurtzite structure with rough surface. The sensor made from the 2% Y-doped ZnO nanosheets exhibits a stronger response toward 100x10(-6) (volume fraction) ethanol, its sensitivity at 300 degrees C is 17.50, and its optimal operating temperature (300 degrees C) is lower than that of the pure ZnO (330 degrees C). The obvious sensitivity (about 2.5) can be observed at the volume fraction of ethanol as low as 5x10(-6), while its the response time is only 2 s at 300 degrees C. Moreover, the Y-doped ZnO sensor has a better selectivity to ethanol than other gases.