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以聚碳硅烷(polycarbosilane,PCS)为先驱体,熔融纺出连续PCS自由原膜,并在190℃下对其进行1,2,3h和6h氧化交联,在900℃预烧及最终分别在1200℃和1300℃烧成,制得系列SiC自由薄膜。采用红外光谱、Raman光谱、X射线衍射、透射电镜与扫描电镜对薄膜进行微观结构与形貌分析。测量了薄膜的室温光致发光特性。结果表明:连续SiC自由膜均匀致密,含有β-SiC微晶、无定形SiOxCy及C簇;薄膜在410～450nm范围内有较强的蓝光发射,1200℃烧结的薄膜随交联时间增加,发光强度增大;而1300℃烧结的薄膜的发光强度相对下降,且交联时间越长强度下降越明显。412nm发光峰可归结于C簇发光;而435nm附近的峰则是薄膜中富含的Si—O,Si—C等键中的缺陷态构成的发光中心,在β-SiC晶粒中电子受到激发与缺陷态产生辐射复合引起发光以及量子表面效应共同作用的结果。
Abstract：Continuous freestanding polycarbosilane(PCS) green films were fabricated by the technique of melt spinning the precursor.The green films were cross-linked at 190 ℃ for 1,2,3 and 6 h and pre-pyrolyzed at 900 ℃,respectively.Then the films were pyro-lyzed at 1 200 or 1 300 ℃ in order to convert the initial PCS into SiC.Their composition and microstructure were characterized by Fourier transform infrared spectroscopy,X-ray diffraction,Raman spectroscopy and transmission electron microscopy.The morphologies of the films were investigated by scanning electron microscopy,and their photoluminescence(PL) spectra were ob-served in the visible range at room temperature.The results show that continuous freestanding SiC films are uniform and dense,and contain β-SiC nano-crystals,amorphous SiOxCy and C clusters.The PL spectra show a wide luminescence band at 410-450 nm.The PL intensity of films pyrolyzed at 1 200 ℃ increases with the increase of the time of cross-linking,but decreases with the increase of the time at the sintering temperature of 1 300 ℃.The PL peak at 412 nm is ascribed to the C clusters.The origin of the PL peak at 435 nm may be attributed to the luminescent centers formed by the Si—O and Si—C bond-related defects in the SiC films;that is,the composite luminescence of radiation generation between electrons existing in β-SiC grains and the defects,and quantum surface ef-fects also in the β-SiC nano-crystals.
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基本信息:
中图分类号:TB383.2
引用信息:
[1]姚荣迁,冯祖德,张冰洁,等.先驱体法制备连续SiC自由薄膜及其发光性能[J].硅酸盐学报,2009,37(02):187-192+197.
基金信息:
国家自然科学基金重点(50532010)资助项目
2009-02-15
2009-02-15