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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。
Poly PCS (polycarbosilane) was used as a precursor to melt the continuous PCS free radical membranes and oxidized at 190 ℃ for 1, 2, 3h and 6h, calcined at 900 ℃ and finally 1200 ℃ and 1300 ℃ firing, a series of SiC free films. The microstructure and morphology of the films were analyzed by infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The room temperature photoluminescence properties of the films were measured. The results show that the continuous SiC free films are uniform and dense and contain β-SiC crystallites, amorphous SiOxCy and C clusters. The films have strong blue emission in the range of 410-450 nm. The films sintered at 1200 ℃ increase with the crosslinking time and emit light The intensity of the film increases; while the luminescence intensity of the film sintered at 1300 ℃ decreases relatively, and the longer the cross-linking time, the more obvious the intensity decrease. The 412nm luminescence peak can be attributed to C cluster luminescence; while the peak near 435nm is the luminescent center of the defect state in the Si-O, Si-C and other bonds rich in the film, and the electron is excited in the β-SiC crystal grain And defects generated by the combination of radiation caused by the combination of quantum effects and surface effects of the results.