多孔硅薄膜的纵向均匀性及其光学特性研究

多孔硅样品使用脉冲电化学腐蚀法经过不同的腐蚀时间制备完成，使用反射光谱、光致发光光谱和SEM对多孔硅薄膜的纵向均匀性以及其光学特性进行了研究，还详细研究了随腐蚀深度变化的折射率和光学厚度(n*d)等光学参数。实验表明：随着腐蚀深度的增加，多孔硅薄膜的平均折射率n降低，即多孔度变大；多孔硅薄膜的光学厚度的形成速度减小；同时，反射光谱表现更弱的干涉性，表明薄膜的均匀性和界面的平整性变差；另外，光致发光谱的强度微弱变强。

Downward uniformity and optical properties of porous silicon layers

Porous silicon (PS) samples were fabricated by pulse current etching using different times. The down-ward uniformity and optical properties of the PS layers have been investigated using reflectance spectroscopy, photo-luminescence spectroscopy, and scanning electron microscopy (SEM). The relationship between the refractive index and the optical thickness of PS samples and the etching depth has been analyzed in detail. As the etching depth increases, the average refractive index decreases, indicating that the porosity becomes higher, and the formation rate of the optical thickness decreases. Meanwhile, the reflectance spectra exhibit less intense interference oscillations, which mean the uniformity and interface smoothness of the PS layers become worse. In addition, the intensity of PL emission spectra is slightly increased.