纳米颗粒镶嵌功能薄膜的力、电、光、磁性能模拟研究

发布时间：2018-04-09 03:08

本文选题：纳米颗粒镶嵌　切入点：功能薄膜　出处：《暨南大学》2015年硕士论文

【摘要】：关于纳米颗粒镶嵌薄膜材料的制备方法及力、电、光和磁性能的实验研究已经有很多。但是,镶嵌纳米颗粒对功能薄膜材料性能影响机理的认识还不够充分,这将成为纳米薄膜领域需要深入探索的一个难点和重点方向。目前,有关纳米颗粒镶嵌薄膜的计算机模拟主要着重于其光学和电学性能的研究,并取得一定的成果,但其力学和磁学性能方面的研究还比较少,纳米颗粒对功能薄膜确切的发光激励机制和导电性影响机理仍是一个有待进一步探索的问题,本文结合第一性原理计算方法,利用Materials Studio软件对纳米颗粒镶嵌功能薄膜的光学、电学、力学和磁学等性能进行模拟研究,模拟计算了多种纳米颗粒镶嵌功能薄膜的光、电、力、磁性能参数,探讨了镶嵌纳米颗粒对功能薄膜材料的性能影响机理。本文利用Materials Studio软件的CASTEP模块进行如下模拟研究:1.对碳(C)纳米颗粒镶嵌基体碳化硅(β-Si C)的纳米颗粒镶嵌薄膜的力学性能进行模拟研究,得到镶嵌纳米颗粒前后体系的杨氏模量、体积模量、剪切模量、泊松比、拉梅常数、各向异性因子、硬度等。结果表明:碳纳米粒子在一定程度上可以提高β-Si C的力学性能;对C/β-Si C镶嵌薄膜的应力应变关系进行分析,得到其X、Y、Z三方向的应力应变曲线很接近,表明该薄膜体系可以视为各向同性材料。2.以半导体碳化硅(β-Si C)为基体,掺杂入钇(Y)原子,构成单原子替位式掺杂结构的Y/β-Si C纳米薄膜,研究其磁学性能。模拟得到Y/β-Si C薄膜体系的磁矩、磁矩分布和上下自旋的态密度图和能带结构图,结果显示该薄膜体系产生了铁磁性,并分析了掺杂Y原子使β-Si C表现出铁磁性的机理。3.通过对掺杂式Y/β-Si C纳米薄膜施加三向压缩载荷,得到Y/β-Si C纳米薄膜的磁矩随静水压缩应力的变化规律。4.在方石英Si O2中镶嵌磷(P)纳米颗粒,对P/Si O2纳米颗粒镶嵌薄膜的光电性能进行模拟,得到P/Si O2镶嵌薄膜的电学性能(能带结构图、态密度图、电子密度、布居数、复介电函数、光电导率)和光学性能(折射率、光吸收谱、反射率、耗散函数),并分析P纳米颗粒对P/Si O2镶嵌薄膜光电性能的影响机理。结果表明:在Si O2中镶嵌P纳米颗粒,在一定程度上可以提高Si O2的光电性能。5.研究磷(P)纳米颗粒含量对P/Si O2纳米颗粒镶嵌薄膜光电性能的影响。建立两个超胞大小相同的方石英Si O2超胞模型,分别在其中镶嵌尺寸不同的P3及P5纳米晶粒,再建立一个超胞大小不同于以上薄膜超胞的2P3/Si O￠模型,模拟计算三种P/Si O2薄膜模型的光电性能并对其进行比较分析。结果表明:当纳米晶粒尺寸和超胞大小在一定范围内时,纳米颗粒含量越大,纳米颗粒镶嵌薄膜的导电性、光吸收性能越强,介电常数、光电导率越大。
[Abstract]:There have been many experimental studies on the preparation and force, electrical, optical and magnetic properties of nanocrystalline inlay films.However, the influence of nano-particles on the properties of functional thin films is not enough, which will become a difficult and important direction in the field of nanocrystalline films.At present, the computer simulation of nanocrystalline mosaic thin films mainly focuses on the optical and electrical properties of the films, and has achieved some results, but the mechanical and magnetic properties of the films are still relatively few.The exact mechanism of luminescence excitation and electrical conductivity of functional thin films by nanoparticles is still a problem to be further explored. In this paper, the optical properties of functional thin films embedded in nanocrystalline particles are studied by Materials Studio software combined with first-principle calculation method.The electrical, mechanical and magnetic properties were simulated. The optical, electrical, force and magnetic properties of the functional films were simulated and calculated, and the mechanism of the influence of the embedded nanoparticles on the properties of functional thin films was discussed.This paper makes use of the CASTEP module of Materials Studio software to do the following simulation research: 1.The mechanical properties of silicon carbide (尾 -Si C) embedded nanocrystalline films were simulated. The Young's modulus, bulk modulus, shear modulus, Poisson's ratio, Lamy constant were obtained.Anisotropy factor, hardness, etc.The results show that the mechanical properties of 尾 -Si C can be improved to some extent by carbon nanoparticles, the stress-strain relationship of C / 尾 -Si C embedded films is analyzed, and the stress-strain curves in three directions are obtained.It shows that the thin film system can be regarded as isotropic material.The magnetic properties of Y / 尾 -Si C nanocrystalline films doped with yttrium (Y) atoms were studied by using semiconductor silicon carbide (尾 -Si C) as the substrate and doped with yttrium (Y) atoms to form monatomic substituted Y / 尾 -Si C nanocrystalline films.The magnetic moment, the distribution of magnetic moment, the density of states and the band structure of the upper and lower spin of Y / 尾 -Si C thin film system are simulated. The results show that the film system produces ferromagnetism, and the mechanism of doping Y atom to make 尾 -Si C ferromagnetic is analyzed.The variation of magnetic moment of Y / 尾 -Si C nanocrystalline film with hydrostatic compression stress was obtained by applying three direction compression load on doped Y / 尾 -Si C nanocrystalline film.In this paper, the optoelectronic properties of P/Si O 2 embedded films are simulated, and the electrical properties (energy band structure, density of states, electron density, population, complex dielectric function) of P/Si O 2 embedded films are obtained.Optical conductivity) and optical properties (refractive index, optical absorption spectrum, reflectivity, dissipation function), and the mechanism of the influence of P nanoparticles on the optoelectronic properties of P/Si O 2 mosaic thin films were analyzed.The results show that the optoelectronic properties of Sio _ 2 can be improved by embedding P nanoparticles in Sio _ 2 to a certain extent.The effect of the content of P) nanoparticles on the optoelectronic properties of P/Si O 2 embedded films was studied.Two supercell models with the same size of the supercell were established, in which different size of P3 and P5 nanocrystals were embedded in the supercellular model, and then a supercell model was established, which was different in size from the supercellular size of the above thin films.The photoelectric properties of three kinds of P/Si O 2 thin film models were simulated and compared.The results show that when the nanocrystalline size and supercell size are in a certain range, the larger the content of nanoparticles, the greater the conductivity, the stronger the optical absorption, the greater the dielectric constant and the greater the photoconductivity of the embedded film.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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