Sensor thick film of ZnO hollow microspheres with average thickness about 200 µm were obtained by spin-coating technique. Its surface was modified by NiO through dropping solution of Ni(NO3)2 into the film towards ratio of mass of Ni(NO3)2 and mass of ZnO is 1%. Subsequently the obtained film was calcined at 500 o C for 2h. Upon calcination, Ni(NO3)2 would reduce to NiO. Ethanol sensing properties of sensor film were determined and compared with the film of pristine ZnO hollow microspheres under UV illumination assisted UV-LED with 365 nm wavelength and 3W power at temperatures from 75 – 125 oC and ethanol vapor concentration levels 125-1500 ppm. The results show that the sensor film with NiO-modified surface reaches significantly high response (6.5) toward 1500 ppm of ethanol vapor at 100 oC.
