Abstract: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 100×10^-6 (volume fraction) ethanol, its sensitivity at 300 °C is 17.50, and its optimal operating temperature (300 °C) is lower than that of the pure ZnO (330 °C). The obvious sensitivity (about 2.5) can be observed at the volume fraction of ethanol as low as 5×10^-6, while its the response time is only 2 s at 300 °C. Moreover, the Y-doped ZnO sensor has a better selectivity to ethanol than other gases.

Key words: ZnO; ethanol; Y-doping; combustion method; gas sensitivity