基于硅纳米晶体的薄膜和块体材料的研究

发布时间：2018-06-05 00:35

本文选题：硅纳米晶体 + 纳米晶体薄膜　；参考：《浙江大学》2014年硕士论文

【摘要】：硅纳米晶体由于尺寸效应因而有着迥异于体硅的光电特性。利用硅纳米晶体薄膜成功制备光电器件是研究人员正努力突破的重要方向。另外,利用硅纳米晶体制备的三维块体材料也展现出巨大的应用潜力,颇具开发价值。本文综合研究了硅纳米晶体及其薄膜和三维块体的结构和性能。在成膜方面,利用溶液法和全气相法将冷等离子体法合成的非有意掺杂SiNCs沉积成膜,基于此制备了硅纳米晶薄膜晶体管(TFT),所制TFT的载流子迁移率在10-3cm2V-1S-1量级,Ⅰ-Ⅴ曲线表明所制备的TFT是具有场效应的,并且证明了非有意掺杂的硅纳米晶体为弱n型半导体材料。将重掺磷和重掺硼的硅纳米晶体颗粒热压,成功制备出了其块体材料,由于它兼具了重掺硅纳米晶体的特点和块体的宏观结构,因此其电学性能十分优异。所获块体材料的致密度最高可达98%,电阻率最低可至0.803mΩ·cm,载流子浓度最高达2.7×1020cm-3。分析发现,最多有大约27%的杂质被电学激活。我们对以上实验结果做出了解释,认为高温下硅纳米晶体的粘性流动在其热压块体成型过程中起着至关重要的作用。硅纳米晶体的表面氧化层有助于热压烧结时晶粒的粘性流动,从而促进有效的颗粒重排。重掺磷的硅纳米晶体比重掺硼的更容易氧化,因此烧结时其颗粒重排更为充分,空隙更少,致密度也更大。同时,高温下硅纳米晶体表面的氧化物自身也会产生粘性流动,打破了原来硅纳米晶体及其表面氧化物的核壳结构,从而使得重掺磷的硅纳米晶体颗粒直接相互接触,组成了有效的电学连接。反观利用重掺硼的硅纳米晶体制备的块体材料,由于致密度低,空隙多,无法大量形成有效电学连接,因此载流子传输通道少,严重制约了其电导的提升。
[Abstract]:Because of the size effect, silicon nanocrystals have different optoelectronic properties from bulk silicon. The successful fabrication of optoelectronic devices using silicon nanocrystalline thin films is an important direction that researchers are trying to break through. In addition, the three-dimensional bulk materials prepared by silicon nanocrystalline also show great application potential and development value. In this paper, the structure and properties of silicon nanocrystalline and its thin films and three-dimensional bulk are studied. In the aspect of film formation, unintentionally doped SiNCs synthesized by cold plasma method was deposited by solution method and gas phase method. Based on this, silicon nanocrystalline thin film transistors were prepared. The carrier mobility of TFT was in the order of 10-3cm2V-1S-1. The I-V curves show that the prepared TFT has a field effect and that the unintentionally doped silicon nanocrystalline is a weakly n-type semiconductor material. Bulk silicon nanocrystals were prepared by hot-pressing the heavily doped and heavily boron-doped silicon nanocrystals. Because of the characteristics of the heavily doped silicon nanocrystals and the macrostructure of the bulk, the electrical properties of the bulk nanocrystals were excellent. The maximum density of the bulk material is 98, the lowest resistivity is up to 0.803m 惟 cm, and the highest carrier concentration is 2.7 脳 1020cm-3. It was found that at most about 27% of the impurities were electrically activated. We explain the experimental results above and conclude that the viscous flow of silicon nanocrystals at high temperature plays an important role in the process of hot pressing bulk forming. The oxide layer on the surface of silicon nanocrystalline is helpful to the viscous flow of grain during hot pressing and sintering, thus promoting the effective particle rearrangement. The heavy phosphorus doped silicon nanocrystalline is more easily oxidized by boron doping, so the particle rearrangement is more complete, the void is less and the density is larger when sintered. At the same time, at high temperature, the oxide on the surface of silicon nanocrystalline also produces viscous flow, which breaks the core-shell structure of the original silicon nanocrystalline and its surface oxides, thus making the heavily doped silicon nanocrystalline particles directly contact each other. An effective electrical connection is formed. On the other hand, the bulk materials prepared from heavy boron doped silicon nanocrystals are unable to form effective electrical connections due to their low density and large number of voids, so the carrier transport channels are few, which seriously restricts the improvement of their conductance.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB383.2

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