Study on the structure and optical properties of ZnO films doped with the III main group elements by sol-gel method

Ga- doped ZnO films and Ga-Al co - doped ZnO films were prepared on glass and Si substrates by sol - gel spin coating. The crystal structure of the sample film was characterized by X-ray diffractometer (XRD), the surface morphology of the film was measured by scanning electron microscope (SEM), the optical properties were investigated by UV-vis spectrophotometer, and the luminescence properties were analyzed by photoluminescence spectrum (PL spectrum).In the experiment on the effect of Ga doping amount on ZnO thin film, Ga doping did not change the structure of ZnO hexagonal wurtzite. A proper amount of Ga will make the grain of the film grow optimally along the c-axis, the grain size becomes smaller, and the film surface becomes smoother and smoother. When Ga doping amount is 3 at%, the film has the best preferred orientation, the most uniform grain growth, and the highest transmittance in the visible region. The effect of Al doping amount on Ga-Al co—doped ZnO thin films was investigated in this paper. The doping amount of Ga was controlled as 3at%, and the doping amount of Al was 0.5 at%, 1.0 at%, 1.5 at%, 2.0 at%, and 2.5 at%. It was found that the addition of an appropriate amount of Al ion would make the grain grow along the horizontal direction, reduce the grain gap on the surface of the film, make the surface smooth and smooth, and improve the crystallization and optical properties of the film. When Ga doping amount is 3.0 at% and Al doping amount is 2.0 at%, the average transmittance of the film in the visible light region is the highest (92%) and the forbidden band width is the largest (about 3.95 ev). At this time, the near-band emission peak of the film is the strongest and the defect luminescence peak is the weakest.