Laser sintering ZnO thick films for gas sensor application

The thick films based on ZnO nanoparticles were prepared by laser sintering with different powers and sintering times for the first time. The microstructure of laser-sintered films was observed by SEM, and their resistance and sensitivity to VOCs as a function of temperature were measured, and compared with the unsintered thick films. The results showed that the laser-sintered ZnO thick films had higher sensitivity than that of the unsintered films. In all. the laser-sintered ZnO thick films, the films sintered at shorter sintering time had the higher sensitivity at the same power, and the sensitivity of the films could be further improved with increasing laser power from 60 to 70 W. The differences in resistance and sensitivity were probably due to the fact that the microstructure of the films and stoichiometric proportion of ZnO changed with the laser power and sintering time.