有Si覆盖的部分氧化多孔硅的光致发光

在４８８ｎｍ的Ａｒ＋激光激发下，Ｓｉ覆盖的部分氧化多孔硅（ＰＯＰＳ）的光致发光谱（ＰＬ）在１．７８ｅＶ处展示了一个稳定的ＰＬ峰，它的强度达到刚制备多孔硅的发光强度．使用Ｘ射线衍射、Ｒａｍａｎ散射、傅里叶变换红外吸收和电子自旋共振等对其发光机理进行了系统的研究．结果表明，这个增强的ＰＬ峰不是起源于量子限制硅晶粒中的带带复合，也不是起源于样品表面局域态或硅晶粒与氧化物之间的界面态的辐射复合．通过与Ｇｅ覆盖的部分氧化多孔硅的相关结果比较，我们认为这个稳定增强的ＰＬ峰起源于氧相关缺陷中心的光学跃迁

Origin of Enhanced Photoluminescence in Si-Covered POPS

Partially oxidized porous Si(POPS) with Si covering shows an enhanced and stable PL peak at 1 78eV, when excited with 488nm line of Ar\++ laser. Its maximal intensity is larger than that of fresh as prepared PS. X\|ray diffraction, Raman scattering, infrared spectroscopy and electron spin resonance indicate that the enhanced PL can not originate from both band\|to\|band recombination in quantum confined Si crystallites and radiative recombination in state localized at the surface or interfacial region between Si and the oxide. In contrast with the corresponding results from Ge\|covered POPS samples,optical transitions in the oxygen\|related defect centers are proposed to be responsible for the observed PL.