The Research On New Fabrication Method And Luminescent Properties Of Si And ZnO Nanocrystals

In this thesis, Si nanocrystals were obtained by reactive sputtering and thermal activated reaction, and its photoluminescence properties, microstructure, phase structure and surface bond structure were measured and analyzed. Moreover, ZnO nanocrystals were prepared by reactive sputtering; the photoluminescence properties and growth model of ZnO nanocrystal were analyzed.Ultra-fine Si nanocrystals with compact Al₂O₃ shell were prepared by using reactive sputtering of SiO₂ and Al targets. Owing to the high RF power of SiO₂ target, Si ions and Si atoms have certain motility, therefore, reaction, 4Al + 3SiO₂→3Si + 2Al₂O₃, can realize at room temperature. The aggregated Si atoms can overcome the barrier energy for nucleation and arrange in the form of nanocrystal. In the experiment, the pure UV PL peak was observed and the emission energy originates from the quantum confinement effect of Si nanocrystals. Meanwhile, a compact Al₂O₃ shell retards the growth of Si nanocrystals and provides ideal passivation on the surface Si nanocrystals.Early works suggested that the thermal treatment above 300°C could lead to the following the reaction: 4Al + 3SiO₂→3Si + 2Al₂O₃. In this thesis, the structure of Si nanocrystals embedded in amorphous SiO₂ matrix was prepared by annealing the Al/SiO₂ composite film and the sandwich-structured film. The size of Si nanocrystals decreases slightly with the reduction of Al content.Thin films comprising ZnO nanocrystals in SiO_x matrix were prepared by using reactive sputtering of SiO₂ and Zn targets without post-annealing processing. The reaction of Zn and SiO₂ leads to the formation of ZnO nanocrystals. The PL measurements show that the SiO_x films containing uniformly dispersed ZnO nanocrystals emit UV light and violet to blue visible light.