用扫描电子显微镜(sEM)对多孔硅的结构进行了分析.结果显示多孔硅具有分形特性,同计算机模拟结果一致;用荧光光谱仪,研究了多孔硅的荧光特性与激发波长的依赖关系.激发光谱测量结果发现,当激发波长从650nm变到340nm时,荧光谱峰位从红端780nm连续蓝移到500nm.综合分析说明:正是由于多孔硅的分形微结构以及量子限制效应,导致了多孔硅的荧光特性随激发波长改变的物理现象.
Using scanning electron microscopy (SEM) and computer simulation, the microstructures of porous silicon have been studied. The results show that the microstructures of porous silicon exhibit fractal characteristics. Characterized with spectrophotometer, the excitation-wavelength dependent photoluminescence of porous silicon has been investigated, and the optical results have demonstra,ted that the photoluminescence spectrum of porous silicon blue shifts continuously from 780 to 500 nm when the excitation wavelength decreases from 650 to 340 nm. The excitation-wavelength tunable photoluminescence of porous silicon can be interpreted in terms of the quantum confinement effect and the fractal microstructures of porous silicon.