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Structural Properties and Size-control of Visible Photoluminescent Porous Silicon

可见光致发光多孔硅的结构性能及尺寸控制

基本信息

批准号：
05452273
负责人：
NITTONO Osamu
金额：
$ 4.54万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

The purposes of this study are to find suitable preparation conditions for porous silicon (PS) layrs having a constant size-distribution of residual Si parts, and to discuss common structural features including emitting parts and their morphology and crystallinity for the p+PS and n+ PS layrs with reference to photoluminescent natures. The PS layrs, formed on heavily doped p-type and n-type silicon wafers of low resistivi less than 0.02OMEGAcm, have been investigated by mainly X-ray multi-crystal diffractometry, supplemented with electron diffraction and scanning electron microscopy and transmission electron microscopy. Main experimental results are as follow : The p+ PS layr presents a wirelike or branched structure of more than 10nm in diameter from the top surface to the bottom part of the PS layr. It was easy to get p+ PS layrs with a constant size-distribution by controlling preparation conditions. The PS layr exibits a slightly larger lattice spacing than the si substate along th … More e direction normal to the surface. The p+ PS layr shows a sharp peak on X-ray diffraction profile measured by X-ray double-crystal diffractometer, indicating that the p+ PS exhibits the same crystallinity as that of the Si substrate. It was also shown that PS layrs which exhibit intensive photoluminescence under He-Cd laser illumination at room temperature are not amorphous, but crystalline, and that the visible photoluminescence is strongly related to the microstructure of PS layr near the surface that shows a spongelike structure consisting of a large number of silicon crystallites of few nm's in size. On the contrary, the n+ PS layr always shows broad diffuse scattering under severl coherent peaks for the n+ PS layr in a large angular range, indicating that the crystallinity of the n+ PS layrs is inferior to that of the p+ PS layrs, probably due to some modifications of the nanostructure of PS layr. It was also found that the n+ PS layrs are composed of several layred pore-structures which are associated with anodization processes, and that halogen-lamp illumination was very effective in forming such a spongelike structure which can emit visible photoluminescence near the top surfaces of the PS layrs.In conclusion, we would like to say that visible light emission comes from only the PS layr that has a spongelike structure consisting of a large number of silicon parts of few nm's in size, and that photoluminescence is probably due to charge carrier confinement in such three dimensional structure. Detailed studies on the correlation between microcrystallite size and photoluminescence peak position or blueshift are now in grogress. Less

本研究的目的是找到合适的制备条件，多孔硅（PS）层具有恒定的尺寸分布的剩余Si部分，并讨论共同的结构特征，包括发光部分和它们的形态和结晶度的p+PS和n+ PS层的光致发光性质。本文用X射线多晶衍射仪为主，电子衍射、扫描电镜和透射电镜为辅的方法，研究了在低掺杂（<0.02 Ω·cm）的p型和n型硅片上形成的PS层。主要实验结果如下：p+ PS层从上表面到下表面呈现直径大于10 nm的线状或分枝状结构。通过控制制备条件，可以得到尺寸分布均匀的p+ PS层。PS层沿沿着方向的晶格间距比Si衬底稍大 ...更多信息 e方向垂直于表面。用X射线双晶衍射仪测得p+ PS层的X射线衍射曲线有一个尖锐的峰，表明p+ PS层具有与Si衬底相同的结晶度。实验还表明，在室温下He-Cd激光照射下，PS膜的光致发光不是非晶态的，而是晶态的，可见光致发光与PS膜表面附近的微观结构密切相关，PS膜表面附近的微观结构是由大量的几个nm大小的硅微晶组成的海绵状结构。相反，n+ PS层在大角度范围内总是在几个相干峰下显示出宽的漫散射，表明n + PS层的结晶度不如p+ PS层，这可能是由于PS层的纳米结构发生了某些改变。还发现，n+ PS层由与阳极化过程相关的几个层状孔结构组成，并且卤素灯照射在形成这样的海绵状结构方面非常有效，该海绵状结构可以在PS层的顶表面附近发射可见光致发光。我们想说的是可见光发射仅来自具有海绵状结构的PS层，该海绵状结构由大量尺寸为几nm的硅部分组成，并且光致发光可能是由于在这种三维结构中的电荷载流子限制。微晶尺寸与荧光峰位置或蓝移的关系的研究正在深入进行中。少