发光多孔硅微结构及其发光起源探讨

The Microstructure and the Luminescence Origin of the Porous Silicon

用制备发光多孔硅样品的常规电化学方法，在未抛光多晶硅表面，成功地制备出了均匀地发射肉眼可分辨的可见光样品。样品的先致发光光谱得到了测定，证明是一种典型的多孔硅光致发光光谱。用扫描电镜对样品的表面形貌、截面结构进行了详细的分析，摄制出了发光多孔硅样品的完整多孔状微结构清晰照片。实验结果认为多孔硅样品可分成三层：表面层、多孔层、单晶硅衬底；而多晶硅表面上制备的发光样品只有两层结构：表面层、多晶硅衬底。文中认为多孔硅可见光发射应来自其表面层，而与层下的多孔层微结构无关。

Using conventional method of making visible light emitting porous silicon, an emitting sample with even visible light,detected by naked eyes. is prepared on unpolished polycrystal silicon wafer. The specimen's photoluminescence spectrum has been obtained. The PL spectrum is demonstrated to be a typical spectrum of visible light emitting porous silicon specimen. The whole structure of the visible light emitting porous silicon specimen has been studied .by using scanning electron microscopy(SEM),and clear microphotograph of the complete microstructure of the specimen is taken. It has been found that the porous silicon specimen can be divided into three layers: Superficial coat, porous layer and crystal silicon substrate. But the visible light emitting sample made on the umpolished polycrystal silicon surface has just two layers: superficial coat and polycrystal silicon substrate. From the results of the above experiments,it is concluded that the visible light of the porous silicon is come from the superficial coat without any relationship with the porous layer.