自组生长的硅纳米管的稳定性研究

文章作者的研究小组在世界上首次合成自组生长的硅纳米管（SiNTs）后,对它的稳定性研究又获得进展.采用5wt%的HF酸对自组生长的硅纳米管的稳定性进行了研究,研究表明HF酸可以去除硅纳米管的氧化物外层,只剩下晶体硅纳米管,说明所得到的硅纳米管是一种稳定结构,因而使其应用研究开发成为可能.研究表明,硅纳米管的稳定性与其生长形成过程密切相关。     

高压条件下合成硅纳米线

Silicon nanowires (SiNWs) were synthesized with silicon monoxide as the only starting material. At the beginning, a protective gas argon was charged into the reaction chamber and the temperature ramp was controlled at 3 ℃·min^-1. The growth condition for SiNWs was controlled at 480 ℃ under the pressure of 2.8 MPa. The morphology and the structure of the products were characterized by TEM, HRTEM and XRD. The results revealed that SiNWs were diamond structure and their diameters were distributed from 5 to 25 nm. The SiNW was single crystal in the central core and was coated with amorphous silica shell at the exterior surface. Influenced by the quantum effect, Raman spectrum of the SiNWs was found to be redshifted. The oxide-assisted growth mechanism was suggested to explain the growth model of self-assembled SiNWs.     

一维硅纳米材料的光学特性

硅纳米线与硅纳米管是两种重要的一维硅纳米材料,由于具有量子限制效应等性能在光电子器件方面具有潜在的应用前景.总结了近年来硅纳米线在光学特性方面的研究进展,重点介绍了本征硅纳米线、掺杂硅纳米线及硅纳米线阵列的光致发光光谱(PL)的最新进展情况,同时涉及了硅纳米管在PL发射光谱方面的研究结果.并对其发展作了展望     

硅纳米线拉曼光谱的研究

声子限制效应会引起本征硅纳米线拉曼光谱红移及不对称宽化,但研究发现其并非引起硅纳米线拉曼光谱改变的主要因素。研究表明,由于在拉曼光谱测量中,通常使用的入射激光功率都在5 mW以上,激光加热会导致很高的局部温度,从而引起拉曼光谱大幅度红移并对称宽化,这是硅纳米线拉曼光谱红移的主要影响因素。另外,激光功率很高时,由激光激发的载流子会与声子发生Fano型干涉,从而使硅纳米线拉曼光谱发生Fano型红移和不对称宽化。除此之外,对小直径本征硅纳米线,声子限制效应导致波矢选择定弛则弛豫,使不在布里渊区中心的声子也可以参与拉曼散射,因而其拉曼光谱中除常见的几个拉曼峰外还会出现新拉曼峰。