【作者】 王军；

【导师】 刘昌龙；

【作者基本信息】 天津大学 ， 材料物理与化学， 2013， 博士

【摘要】 论文围绕离子注入透明绝缘材料中纳米颗粒的合成、表征与调控开展了相应研究，主要内容与结果如下：⑴对30keV的C离子以不同剂量注入的有机玻璃样品进行了结构、光致发光(PL)和光反射特性的研究，结果表明：样品的PL强度不随C离子剂量单调变化；样品的PL响应与氢化无定形C纳米颗粒的形成及其构型变化有关；由于注入层的结构变化，样品的光反射率既与波长有关，也与C离子剂量有关。⑵对45keV的Cu和Zn离子以相同剂量(1×1017cm-2)顺序注入的SiO2样品进行N2气氛中500°C退火，成功地合成了CuZn合金纳米颗粒，其表面等离子体共振(SPR)峰位于515nm处。600°C退火导致合金纳米颗粒分解，并在基底中形成Cu纳米颗粒，相应的SPR峰出现在574nm处。由于Cu+溶质的激发，退火后的样品表现出弱的荧光发射特性，PL峰位于558nm附近。⑶用50keV的Zn离子和35keV的Ag离子按不同顺序注入SiO2可以合成不同种类的金属纳米颗粒。在先Zn后Ag注入的样品中所合成的为Ag纳米颗粒，由于成核点的增加和Ag注入子的沉积增强过程，这些Ag纳米颗粒具有较高的体积分数、较小的尺寸和较窄的尺寸分布以及改善了的介电环境，因此，样品在435nm处呈现出一个很强的SPR峰，改变Zn离子剂量对SPR峰的影响不大。在先Ag后Zn注入的样品中所合成的为Ag、Zn单质和Ag–Zn合金纳米颗粒的混合物，对应的吸收带出现在260–550nm之间。⑷对45keV的Cu离子以1×1017cm-2剂量注入的SiO2样品，分别用500keV的Xe和Ar离子辐照，以改善Cu纳米颗粒的尺寸和空间分布以及样品的光吸收特性。结果表明：剂量为2×1016cm-2的Xe离子辐照后，Cu纳米颗粒的平均直径从7.3nm增加到8.5nm，高密度的大尺寸Cu纳米颗粒几乎排列在相同的深度，该深度远远超出了Cu离子的投影射程；一个临界的Xe离子剂量大约为1×1016cm-2；在相同能量和剂量下，Xe离子辐照比Ar离子辐照具有更好的改性效果。⑸提出并实践了一种两阶段处理方法，即先用500keV的Xe离子以1×1016cm-2剂量进行辐照，再用21keV的Ag离子以2×1016cm-2剂量进行注入，目的是在SiO2中合成准二维排列的Ag纳米颗粒，并同时抑制Ag注入子的溅射损失。实验结果不仅证实了上述方法的可行性和有效性，而且还表明Ag纳米颗粒的多晶化也是影响复合材料光吸收特性的一个重要参数。更多还原

【Abstract】 Several researches were performed in order to fabricate nanoparticles (NPs) in thetransparent dielectrics by means of ion implantation, as well as to control the size andspatial distributions of the embedded NPs. The main contents and results are given asfollows.(1) Polymethylmethacrylate (PMMA) slices were implanted with30keV carbonions at different fluences, and their structure, photoluminescence (PL) and reflectivitywere examined. A luminescent band with one peak could be detected from each sample,whose intensity did not vary in parallel with ion fluence. Such PL response was relatedto the formation of hydrogenated amorphous carbon nanoclusters and their evolutionin configuration with ion fluence. The structural changes induced by ion implantationcould be responsible for the fluence-and wavelength-dependent reflectivity of sample.(2) CuZn alloy NPs embedded in SiO2were fabricated by sequential implantationof45keV Cu and Zn ions at the same fluence of1×1017cm-2together with subsequentannealing at500oC in nitrogen ambient. Such alloy NPs presented an intense surfaceplasmon resonance (SPR) peak at about515nm. After600°C annealing, the alloy NPswere decomposed, and only Cu NPs could be found in the substrate, which induced aSPR peak at about574nm. The weak PL peak around558nm detected from theannealed sample could be attributed to the excitation of Cu+solutes.(3) Nanometer metallic colloids were fabricated in SiO2by dual implantation of50keV Zn and35keV Ag ions in different implantation sequences. In the case of Znions followed by Ag ions, Ag NPs were formed, which had smaller size, narrower sizedistribution and higher volume fraction as well as modified dielectric environmentowing to the increased nucleation sites and the enhanced deposition process of Agimplants. As a result, the Zn first and then Ag implanted samples presented an intenseSPR peak around435nm. Variation of Zn ion fluence only caused slight change of theSPR peak. In contrast, a dual implantation of Ag first and then Zn ions resulted in theformation of Ag, Zn and Ag–Zn alloy NPs, which contributed a weak absorption bandbetween260and550nm.(4) SiO2samples implanted with45keV Cu ions at a fluence of1×1017cm-2wereirradiated by500keV Xe and Ar ions, respectively, in order to tailor the size andspatial distributions of the embedded Cu NPs along with their optical absorptionproperty. After Xe ion irradiation at a fluence of2×1016cm-2, the average diameter of Cu NPs was increased from7.3to8.5nm, and especially, the larger Cu NPs withhigher particle density were formed beyond the projected range of Cu ions and nearlyaligned at the same depth. Optical absorbance spectral measurements not only revealedin principle a critical Xe ion fluence of1×1016cm-2, but also demonstrated that Xe ionirradiation was more effective to modify the Cu SPR peak than Ar ion irradiation at thesame energy and fluence.(5) A two-step method, i.e.,500keV Xe ion irradiation to a fluence of1×1016cm-2and subsequent21keV Ag ion implantation to a fluence of2×1016cm-2, was proposedand employed to fabricate the quasi-two-dimensional Ag NPs in SiO2as well as tosuppress the sputtering loss of Ag implants. The experimental results not onlysubstantially evidenced the feasibility and validity of this method, but also revealedthat the polycrystallization is an important parameter affecting the SPR property of AgNPs.更多还原