【作者】 李兴华；

【导师】 刘益春；

【作者基本信息】 东北师范大学 ， 凝聚态物理， 2010， 博士

【摘要】 本论文以静电纺丝技术为基础,基于相分离原理实现了单管电纺连续纳米管材料、与溶胶凝胶、气相输运方法、氮化法结合制备了ZnO基低维复合纳米结构材料及III-V族共掺及合金材料,研究了ZnO基低维复合纳米结构、III-V族共掺及合金材料以及ZnO:N薄膜的结构和发光性质,具体工作如下:基于相分离原理实现单管电纺连续纳米管材料。通过控制乙醇对挥发过程的影响,TEOS对相分离过程的影响,以及纺丝电压对弯曲和拉伸过程的影响,可以调控PVP/TEOS连续纳米管结构的直径,壁厚,以及二者的比。通过在空气中煅烧PVP/TEOS连续纳米管至600oC获得SiO₂纳米管,通过Mg蒸汽还原法成功的制备了硅纳米管。该方法是大面积制备PVP/TEOS复合纳米管及硅纳米管的有效方法。这些一维纳米管材料有可能应用于传感器、过滤器、锂离子电池负极材料、以及太阳能电池材料等领域。通过单管电纺技术制备出单分散ZnO量子点于PVP复合纳米管壁中。由于量子点的高度分散性,以及PVP分子对量子点表面缺陷的钝化作用,光致发光和共振拉曼谱展现了较窄的带边发射和较弱的激光热效应。观察到了由于量子限域效应所导致的带隙的蓝移,激子束缚能的增加,以及激子声子相互作用的弱化。利用气相输运沉积方法制备出一维SiO₂/ZnO核壳纳米结构材料。室温和低温的发光光谱表明ZnO纳米壳层的质量较好。其发光的反常温度效应表明界面对ZnO的纳米结构的发光有显著影响。通过电纺及氨气氮化技术制备了N-In共掺杂ZnO纳米纤维。通过退火改善了氮化后样品的结晶质量,减少了缺陷密度,提高了可见光响应性能,使得共掺杂的ZnO在类太阳光谱照射下能够降解罗丹明B染料。研究了氮化ZnO/ZnGa₂O₄复合纳米纤维过程中(Ga_1-xZn_x)(N_1-yO_y)合金纳米结构的形成与演化。由于纳米结构的原因,合金的形成温度显著降低,既保证了氮原子的引入,同时又确保了锌原子的低损失率。325 nm激光激发的拉曼光谱表现出双模的行为,可以用于估计(Ga_1-xZn_x)(N_1-yO_y)合金组分的比例。研究表明通过共掺杂及合金化的方法可以调控ZnO的电子结构拓展其在可见光催化、分解水方面的应用。研究了ZnO:N薄膜的发光性质和微结构的稳定性。紫外区的与受主相关的发射说明氮元素确实能够起到受主的作用。蓝光和绿光发射在82K、低激发密度时占主导作用,可能是由施主向价带跃迁导致的。红光发射随温度和激发密度的升高呈现蓝移,可能是源于深施主受主对发射。表明氮进入ZnO晶格中除了受主作用外还可能引起一些深的施主缺陷。变温XPS研究了ZnO:N薄膜的微结构及热稳定性,分析表明位于396和398 eV的峰可能分别来自富氮和富氧环境中的氮替氧（β-和α-NO）。与β-NO相比,作为浅受主的来源α-NO可以稳定到723 K。更多还原

【Abstract】 In this dissertation, a simple method was proposed for controllable electrospinning polymer nanotubes via a single capillary; moreover, low dimensional ZnO composite nanostructures were prepared by combining sol-gel method, vapor transport deposition, and nitrification method with electrospinning technology; the structure and optical properties of these materials and ZnO:N thin film were also studied as follows:PVP/TEOS nanofibers and nanotubes have been electrospun by a single capillary. The diameters of products, the thicknesses of nanotubes walls, and the ratio of the nanotube wall to the nanotube diameter could be varied by controlling the effects of ethanol on evaporation process, TEOS on phase separation process, and the applied voltages on bending and stretching process. SiO₂ nanotubes could be fabricated by calcinating the PVP/TEOS composite nanotubes in air at 600℃. Moreover, silicon nanotubes could be prepared by magnesiothermic reduction of SiO₂ nanotube templates. The methods are effective to prepare PVP/TEOS composite nanotubes and silicon nanotubes. Such nanotubes are of interest for a broad range of applications in areas such as sensors, filter technologies, lithium ion batteries, and solar cells, etc.Highly dispersed ZnO QDs in PVP nanotubes have been prepared by a single capillary electrospinning. The composites exhibit narrower band edge emissions and less laser thermal effects due to the well dispersion of ZnO QDs and the passivation of PVP molecules on the surface defects of ZnO QDs. Thus, quantum confinement effects on the PL properties of ZnO QDs have been observed including blue shifted band gap, enlarged exciton binding energy and less exciton-LO phonon interaction. SiO₂/ZnO nanocables are obtained by the combination of electrospinning technology and vapor transport deposition procedure. The nanoshells of ZnO show good photoluminescence properties suggesting their high qualities. The anomalous behavior in temperature-dependent PL spectra is attributed to the carrier injection from thermal ionized carriers from the interface of the nanocables.By electrospinning technology and nitrifing process, N-In co-doped ZnO nanofibers have been prepared. By annealing the nitrified samples in air, the defect densities are decreased and the crystal qualities and visible photo-responsibilities were improved. The co-doped nanofibers photocatalyst shows good visible photocatalytic activity toward decomposing organic dye rhodamine B. The formation and evolvements of (Ga_1-xZn_x)(N_1-yO_y) alloy nanostructures are also studied. The alloys formation temperature is decreased remarkably due to their nanostructures morphologies. Thus, nitrogen atoms could be introduced into the nanofibers while zinc atoms could hardly lost in the materials. The Raman spectra were also investigated in detail. By co-doping and alloying methods, the electronic structure of ZnO could be tuned. The results could be applied for visible light photocatalyst of decomposing organics and visible light driven overall water splitting.PL properties and thermal stabilities of ZnO:N local structures are investigated. Acceptor related UV emissions indicate that the doped nitrogen atoms could act as acceptors. The blue and green emissions might be related to the donor to valence band transitions, while the red emissions origin from deep DAP transitions. Thus, nitrogen not only acts as an acceptor, but also induces some complex defects acting as deep donors. Temperature-dependent XPS measurements suggest that XPS peaks at ³96 and ³98 eV originate from the NO in N- and O-rich local environments （β- andα-NO）. Compared toβ-NO, theα-NO, as a shallow acceptor, is more thermally stable up to 723 K. The careful studies on the emissions and local states of N impurity are helpful for achieving the stable, high-quality p-ZnO:N.更多还原