Enhanced ethanol sensing properties based on Sm2O3-doped ZnO nanocomposites

ZnO nanocomposites doped with 2, 4, 6 and 8 wt% samaria (Sm2O3) were prepared by a novel sol spray combustion method. The samples were characterized by XRD, FESEM, EDX, UV-vis DRS and Raman techniques. The XRD results show that all samples containing various amounts of Sm2O3 have a hexagonal wurtzite structure. UV-vis spectra show that the addition of Sm2O3 did not affect the band gap of ZnO. Raman spectra exhibit that the Sm2O3-doped ZnO nanocomposite keeps the crystal structure of the bulk ZnO and possesses more surface defects. The influence of Sm2O3 dopant on the response and selectivity for ethanol detecting of the sensor based on ZnO nanoparticles was investigated. The sensors' responses were measured in the presence of 100 ppm of ethanol, formaldehyde, methanol and toluene. As 4 wt% Sm2O3 was added to ZnO, the response to ethanol at various temperatures was significantly enhanced. The results reveal that doping with Sm2O3 may be a promising route for the production of ZnO-based gas sensors with good ethanol sensing properties.