| Silicon (Si) is the leading material of microelectronic devices, but the nature of indirect band gap of Si hinders its applications in integrated optoelectronics. To develop Si-based optoelectronic integration by coupling the mature technology of Si microelectronic integration with Si-based light-emitting material will essentially meet the increasing demand of the great progress in the information technology. Thus, the study of luminescence properties of Si-based materials has become a very active field of research.The study of Si-base light-emitting materials has made great progress in recent years. To sum up, two types of model have priority in explaining the origin and mechanism of visible PL in Si-base light-emitting materials. But in view of the reported results, the properties of materials are badly influenced by preparation process. In order to clarify the origin of PL and enhance the luminescence efficiency of materials, the study of the relationship between preparation process and PL properties is very important.Our study is mainly focused on the luminescence properties of Si-based thin films and the influence of O and N impurity. Thin films were prepared by PECVD and rf-sputtering, the influence of O and N content and the Ts (substrate temperature) on the structure and luminescence properties of films were studied; Nano-Si powder and nano-Si/SiOa composite films were prepared by coupling ball milling and sol-gel technologies, structure and luminescence properties of this kind of powder and film were also studied. As a result, a serial of intense PL bands were observed in the visible and UV range in O and N doped thin films, the related PL mechanisms were discussed.Intense PL band at 300-570nm, whose central position was found red-shifted with the increase of O content, was observed in the a-SiHxOy thin films fabricated by PECVD. Thin films with strong blue PL peaks were prepared by plasma oxidation, and the result directly proved that the blue PL peaks were originated from Si-O defect levels. Besides two PL bands located at 250-400nm and 650-700nm, two groups of distinguishable PL peaks were observed for the first time in the a-SiOxNy thin films, which centered at about 370nm and 730nm, respectively. The intensity of distinguishable PL peaks increased with the increasing N content in the films, and the central positions of the above two PL bands were influenced by both the content of O and N. It is suggested that these PL were originated from luminescence centers related to Si-O and 0-Si-N defects.Through comparing above results with those of thin films fabricated by rf-sputtering technology, it is indicated that H has almost no influence on the PL properties of films, but different preparation methods of thin films will result in quite different PL properties. In the films prepared by rf-sputtering, two new green PLbands, which strengthened with the increase of N content in the thin film, were observed except those PL bands corresponding to the result of PECVD. Moreover, the intensity of every PL band is strongly affected by the Ts. Intense green and violent emitting can be obtained when the Ts during deposition is at 750癈, and the content of O and N impurity is moderate.Nano-Si embedded SiO2 composite thin film were fabricated by using ball-milling and sol-gel technology, it is found that the red PL band located at about 730nm is affected by the interface characteristic of nano-Si, this indicated that the red emitting resulted from nc-Si is also rely on its interface characteristic.To summarize, intense near UV, violent, blue, green, and red emitting can be obtained in Si-based thin films through 0 and N doping. As for the PL mechanism, except the red band, the rest are all originated from luminescence defects related to impurity, and the luminescence centers are affected by configuration of impurities, while the red emitting band may attribute to the quantum confinement effect of nano-Si, but will also rely on its interface characteristic.
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