激发波长对多孔硅荧光特性的影响

Excitation-Wavelength Dependent Photoluminescence from Porous Silicon

用荧光光谱仪测量了多孔硅样品的任一给定点的荧光特性与激发波长的依赖关系,发现当激发波长从650nm变到340nm时,该点的荧光谱峰位从780nm连续蓝移到490nm。用扫描电子显微镜(SEM)对多孔硅的截面进行了分析,结果显示多孔硅具有分形特性,这同作者的计算机模拟结果一致。结合多孔硅样品的激发光谱测量结果,多孔硅的荧光特性随激发波长改变的现象可以归因于多孔硅的分形结构以及量子尺寸效应。

With the technique of fluorescence spectral analysis, the dependence of the fluorescence from porous silicon on the excitation wavelength was investigated. It was found when the excitation wavelength decreases from 650 to 340 nm, the fluorescence spectrum of porous silicon blue shifts continuously from 780 to 490 nrn. Using scanning electron microscopy （SEM） and computer simulation, the cross-sectional structures of porous silicon were studied. The authors＇ results showed that the microstructures of porous silicon exhibit fractal characteristics. With the additional information extracted from the excitation spectra of porous silicon, the authors＇ results can be interpreted in terms of the quantum size effect and the fractal structures of porous sillcon.