《ZnO纳米管的第一性原理研究》由会员分享，可在线阅读，更多相关《ZnO纳米管的第一性原理研究（60页珍藏版）》请在金锄头文库上搜索。
1、 西安建筑科技大学硕士学位论文 ZnO 纳米管的第一性原理研究 专 业：材料物理与化学 硕 士 生：雷哲锋 指导教师：王发展 教授 摘 要 氧化锌(ZnO)是一种特殊的金属氧化物，具有较宽的带隙(3.37eV)和较大激子结合能(60meV)，并具有良好的近紫外散射、透明传导性能、压电性能、生物适应性等, 将成为人类最重要的功能材料之一。 近年来相关理论和数值算法的飞速发展, 使得基于密度泛函理论的第一性原理方法在凝聚态物理、量子化学和材料科学中得到非常广泛的应用。 本论文应用Materials Studio 5.5第一性原理软件的Castep模块以及Gulp模块, 研究了ZnO纳米管的电子结构
2、、发光性能的掺杂机理以及P-型掺杂改性等, 主要工作如下： l、采用基于密度泛函理论(Density functional theory)的计算方法, 研究了n=4,6,9 的锯齿型(n,0)ZnO 单壁纳米管的电子结构, 结果表明：锯齿型 ZnO 单壁纳米管是一种直接宽禁带半导体, 其能隙随着横截面的增大而小量增大, 并分析了锯齿型单壁纳米管的核外电子分布图; 2、采用热蒸发法制备得到掺Cd含量为3.3at%的ZnO纳米管, 室温光致发光谱(PL)显示, 由于Cd的掺入, ZnCdO纳米管的紫外近带边发射 (UV NBE)从纯ZnO的3.26eV红移到3.20eV附近。 应用基于密度泛函理论
3、的计算方法, 研究了锯齿型 （9,0）ZnMO(M=Cd,Mg)单壁纳米管的电子结构。 分析发现Cd掺杂ZnO纳米管能隙值的计算结果与实验结果拟合良好, 能隙值随着掺杂量增加逐渐减小, 出现红移; 而Mg掺杂纳米管则不同, 能带变化没有规律性; 3、研究了ZnO纳米管的P-型掺杂改性机理。采用基于密度泛函理论的计算方法, 系列的研究了锯齿型（9,0）ZnO单壁纳米管、Li, N 分别掺杂以及Li-2N共掺杂的ZnO纳米管的能带结构、总体态密度、分波态密度。分析发现虽然Li原子单独掺杂不会对纳米管能带结构产生明显影响, 但是Li-2N共掺杂比N单独掺杂ZnO纳米管的结构更加稳定, 而且是p型简并
4、半导体。 本论文得到下列课题的支持：陕西省自然科学基础研究计划重点项目(编号:2011J2009) 关关 键键 词词：ZnO; 第一性原理; 纳米管; 电子结构; 掺杂 论文类型：基础研究 西安建筑科技大学硕士学位论文 First-principles study on ZnO nanotubes Specialty: Materials Physics and Chemistry Name: Lei Zhe-Feng Instructor: Prof. Wang Fazhan Abstract Zinc oxide is an especial kind of metal oxides, w
5、hich has wide band gap (3.37eV) and large exciton binding energy (60meV) at room temperature. Furthermore, because of the good nearly ultraviolet scattering, transparent conduction performance, piezoelectric properties, biocompatibility, etc., ZnO would be one of the most important function material
6、s. For the past few years, with the rapid development of related theory and numerical algorithm, the application of First-principles method in condensed matter physics, quantum chemical and materials science based on DFT (Density Functional Theory) became diffusely. By using the Castep module and Gu
7、lp module of the software named Materials Studio 5.5, we have studied electronic structure, luminous property doping mechanism, P-type doping of ZnO nanotubes. The main work is as follows: l. The electronic structures of the zigzag single-wall ZnO nanotubes have been calculated by first-principles a
8、pproach based on the density functional theory. The calculated results indicate that the zigzag single-wall ZnO nanotube is a direct band gap semiconductor material. The band gap is increasing by broaden the cross section of zigzag single-wall ZnO nanotube. The electron density of zigzag single-wall
9、 ZnO nanotubes has been analysed too. 2. The Cd-doped ZnO nanotubes with Cd content of about 3.3at% were synthesized with thermal evaporation method. The room-temperature photo- luminescence (PL) spectra shows that the ultra-violet(UV) near-band-edge (NBE) emission of the ZnCdO nanotubes exhibit a s
10、light red shift from 3.26eV to 3.20eV, which is attributed to Cd substitution. Then based on the density functional theory, the electronic structure of zigzag (9, 0) single-wall ZnMO (M=Cd, Mg) nanotubes were studied. The results show that, the calculation results of Cd doped ZnO nanotubes is 西安建筑科技
11、大学硕士学位论文 conform to experimental results, the band gap value gradually decrease follow the doping amounts increased, appear red-shift; the Mg-doped ZnO nanotubes is different, the Eg was ruleless changed. 3. The P-type doping modification mechanism of ZnO nanotubes. Based on the density functional t
12、heory, the electronic structure of pure ZnO and N, Li, and Li-N co-doped ZnO nanotube has been investigated. The band structure, total density of states, and partial density of states of them were studied. The calculated results show that Li-2N codoped is more in favor of the formation than N solely
13、 of doped zigzag single-wall ZnO nanotube, though the Li doping has less influence to the structure, furthermore it is a p-type degenerate semiconductor. This work was supported by the project of nature science foundation research plans, Shaanxi province (Contract No.2011J2009) Keywords: ZnO; First-principles; nanotube; electronic structure; doped Thesis type: Basic research 西安建筑科技大学硕士学位论文 I目 录 1 绪论 .1 1.1 引言 .1 1.2 ZnO 的基本性质.1 1.3 ZnO 的纳米结构.3 1.4 国内外研究现状 .6 1.5 本文的主要研究工作 .9 2 Material Studio 软件介绍.10 2.1 Hartree-Fock 近似.10 2.2 密度泛函理论 .
