【摘要】 以含碳的二氧化硅干凝胶为原料,采用碳热还原法制备了孪晶结构β-SiC纳米线。通过场发射扫描电镜、X射线衍射和高分辨透射电镜等测试分析表明,SiC纳米线具有六角形的横截面,直径50～300nm,沿着纳米线生长方向具有准周期性的(111)面孪晶结构。结合气-固生长机理及(111)密排面堆垛次序的变化讨论了孪晶纳米线的生长机理。光致发光谱表明,SiC纳米线在470nm附近有数个相对β-SiC体单晶的发光特征蓝移,且分裂的发光峰。这种发光现象可解释为堆垛层错导致相互隔离的β-SiC纳米片段的量子尺寸效应。更多还原

【Abstract】 Twinned β-SiC nanowires were synthesized by the carbothermal reduction of a carbonaceous silica xerogel. Results of field emission scanning electron microscopy, X-ray diffraction and high-resolution transmission electron microscopy indicate the twinned β-SiC nanowires possess a hexagonal cross section and have typical diameters of 50-300 nm. A quasi-periodically twin structure with (111) plane as the boundary along the SiC nanowires was observed. The formation of the twinned nanowires was discussed based on the vapor-solid growth mechanism and transition of stacking faults of the hexagonal {111} close-packed planes. Some separated blue-shifted photoluminescence peaks around 470 nm were measured. The separated blue-shifted emission peaks are thought due to the quantum confinement of nanoscaled twin segments along each nanowire rather than the apparent diameter of the nanowires.更多还原