硅纳米线的X射线吸收谱与X射线激发发光谱研究

A X-Ray Absorption Spectroscopy and X-Ray Excited Optical Luminescence Study of Silicon Nanowires

摘要:

采用X射线吸收精细结构谱（XAFS）和X射线激发发光谱（XEOL），在Si的K边和L3.2边研究了硅纳米线的光电特性。在XAFS中虽然没有观察到跃迁边的明显蓝移，但可观察到跃迁边平缓上升和特征峰逐渐变得模糊，这意味着长程有序被破坏并产生了显著的量子尺寸效应，XAFS测量的是各种小尺寸的硅纳米线分布的平均特性。XEOL的结果表明硅纳米线的发光来自于包裹的二氧化硅和镶嵌在氧化物层中的纳米硅晶体颗粒以及硅与二氧化硅之间的界面。

Abstract:

X-ray absorption fine structures(XAFS)and X-ray excited optical luminescence(XEOL)at the Si K and Si L3,2 edge have been used to investigate the optoelectronic properties of Silicon nanowires.Although no noticeable blueshift of edge jump was observed in XAFS,a less steep rise and the blurring of spectral features was observed,indicating considerable degradation in the long-range order and small size effects.XAFS probes the average of a distribution of wires of various sizes of which the majority is too large to exhibit detectable quantum confinement behavior.The results of XEOL indicates that the luminescence of Si nanowires originate from the encapsulating silicon oxide,the quantum-confined silicon crystallites embedded in the oxide layer,and the interface states between silicon and silicon oxide.