Study On Technics And Performance Of--Semiconductor Oxygen Sensor

Based on a detailed study of sensing and conducting mechanism of n type SrTiO₃, further researches were carried out on the SrTiO₃ by La & Nb doping in this dissertation. An optimal doping quantity was made out by experiment. Remarkable n-type SrTiO₃ oxygen sensors were fabricated by solid phase synthesis method and Sol-Gel method. Comparison between solid synthesis method and Sol-Gel method showed that Sol-Gel method had many shortcomings and further work is necessary. Heat treatment for the stability of sensor was also investigated in this paper. Also, precious metal Pt as surface catalyst was doped to shorten the response time in some samples; Besides, we got a superiority sensitivity by Sol-Gel method at 400℃.X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) was employed to analyze the samples. XRD showed that the doped samples fabricated by solid phase synthesis and Sol-Gel attached good perovskite; SEM images indicated that the grains of the samples fabricated by solid phase synthesis are small and loose, which is propitious to oxygen absorption, while samples prepared by Sol-Gel didn't show any advantages in micro morphology. SEM backscattering image showed that Pt distributed on the samples surface uniformly, and the latter's uniformity of particle size was better.