He离子注入的尖晶石中Au纳米颗粒的合成研究

利用20 keV的He离子注入表面蒸镀了Au薄膜的尖晶石（MgAl2O4）样品, 随后对注入样品进行了退火处理。 在紫外可见光谱上观察到了由于金属纳米颗粒的存在而引起的较强的表面等离子体共振吸收峰, 提供了材料中金属纳米颗粒形成的光谱证据。 并对形成的Au纳米颗粒的尺寸随退火温度以及He注入剂量的变化进行了研究。 Spinel deposited with a thin Au film was implanted with helium ions, and annealed in vacuum condition subsequently. The surface Plasmon resonance absorbance peak due to the existence of metallic nanoparticles in the dielectric matrix was observed on the Ultraviolet Visible Spectrometry, indicating the formation of metallic nanoparticles in spinel. The dependence of Au particles size with annealing temperature and implantation doses was also investigated.     

Surface Disorder of GaN Irradiated by Highly Charged Arq+-Ions

The surface damage to gallium nitride films irradiated by Ar^q＋ （6≤q≤16） ions at room temperature is studied by the atomic force microscopy. It is found that when charge state exceeds a threshold value, significant swelling was turned into obvious erosion in the irradiated region. The surface change of the irradiated region strongly depends on the charge state and ion fluence. On the other hand, surface change is less dependent on the kinetic energy nearly in the present experimental range （120 keV≤Ek≤220 keV）. For q≤14, surface of the irradiated region is covered with an amorphous layer, rough and bulgy. A step-up appears between the irradiated and un-irradiated region. Moreover, the step height and the surface roughness are functions of the ion dose and charge state, and increase with the increase of dose and charge state. Especially at and near boundary, a sharp bump like ridges in irradiated areas is observed, and there appear characteristic grooves in un-irradiated areas. For q=16, surface of the irradiated region was etched and erased.     

高电荷态离子$lt;sup$gt;126$lt;/sup$gt;Xe$lt;sup$gt;$lt;i$gt;q$lt;/i$gt;+$lt;/sup$gt;引起GaN表面形貌变化研究

用不同电荷态的¹²⁶Xe^q+离子（9≤q≤30）在室温下轰击GaN晶体表面,经原子力显微镜分析表明,当q>18,辐照区域由隆起转为显著的刻蚀.被轰击后的GaN晶体表面形貌主要取决于入射离子的电荷态.同时,样品表面形貌还与入射离子的剂量和入射角有关;在实验参数范围,与入射离子的初动能没有明显关系（180 keV≤E_k≤600 keV）.当入射离子的电荷态q=18,与样品表面法线成60°角倾斜入射和垂直表面入射时,样品的表面几乎没有变化,只是倾斜入射后有很微小的隆起;当q＜18时,样品表面膨胀隆起,粗糙度增强,倾斜入射时表面隆起比垂直入射时更明显,而且都有清晰的峰状分界区;当q＞18时,样品表面被蚀刻呈凹陷状,有明显的齿状刻痕,且侵蚀深度与离子剂量近似呈线性关系,倾斜入射时的刻蚀深度大于垂直入射时的刻蚀深度. 关键词： 高电荷态离子 GaN晶体 原子力显微镜 表面形貌     

惰性气体离子注入铝镁尖晶石合成金属纳米颗粒的探索

实验在表面蒸镀了金属(Cu,Au)薄膜的尖晶石(MgAl₂O₄)样品中注入惰性气体离子(Ar,He),随后对注入样品进行了退火处理.在紫外可见光谱上观察到了由于金属纳米颗粒存在引起的较强的表面等离子体共振吸收峰,提供了材料中金属纳米颗粒形成的证据.采用这种方法在材料中引入金属纳米颗粒,发现影响金属纳米颗粒形成的因素除了退火温度外,金属薄膜厚度的影响不可忽略. 关键词： 金属纳米颗粒 离子注入 惰性气体离子 紫外可见光谱     

聚乙烯醇缩醛膜阻气性能的研究

 为了提高激光靶丸的阻气性能，用戊二醛对阻气层材料聚乙烯醇进行交联改性。在17份完全相同的10 mL质量分数3%的聚乙烯醇(PVA)和20 μL浓盐酸混合溶液中，分别加入从300 μL到1 700 μL的戊二醛(GA)，交联反应后，测量缩醛膜的阻气性能，并计算渗透系数。 结果表明，随着缩醛膜中戊二醛含量的增加，缩醛膜渗透系数的变化规律是：从减小到增加到不变再到增加；当戊二醛的含量是800 μL时，缩醛膜的渗透系数最小，阻气性能最好。     

高电荷态氙离子辐照下的6H碳化硅表面纳米结构变形（英）

高电荷态离子比普通的离子携带较高的势能,势能在材料表面的瞬间释放,能在材料表面形成nm量级的结构损伤。它在纳米刻蚀、小型纳米器件、纳米材料、超小尺寸半导体芯片制作、固体表面处理和固体结构分析等领域具有广泛应用前景。因此对高电荷态重离子（Xeq+）引起半导体材料表面（6H-SiC）纳米结构变形进行了研究。采用Xe18+和Xe26+离子,选取从11014到51015 ionscm-2逐渐递增的剂量,以垂直和倾斜60角两种入射方式辐照6H-SiC薄膜样品, 经原子力显微镜分析表明,辐照后的表面肿胀凸起。对于Xe18+离子辐照的样品,辐照区至未辐照区边界的台阶高度随离子剂量增加而连续增大,而对于Xe26+离子辐照的样品则先增加而后减小。在相同入射角和剂量条件下,Xe26+离子辐照样品形成的台阶高度大于Xe18+离子辐照形成的台阶高度,在相同离子和剂量的条件下,垂直照射时形成的台阶高度大于倾斜照射时形成的台阶高度。根据损伤机理和实验数据,首次初步建立了一个包括势能、电荷态、入射角和剂量等物理量的理论模型来预测高电荷态离子在半导体材料表面形成的纳米结构变形。暗示了高电荷态离子的潜在的应用价值及进一步研究的必要性。     

氢气在多层球壳中扩散过程的模拟计算

 从Fick第二定律出发，推导了氢气在多层球壳中，扩散过程的浓度分布表达式，即氢气浓度与扩散时间和扩散距离的关系。每层中，在一定的扩散时间内，一定量的氢气的扩散浓度与扩散深度之间近似为抛物线关系，说明渗透物沿着聚合物链段膨胀的方向进行扩散。在同一位置，一定量氢气的浓度，随着时间的延长而增加，说明渗透物使聚合物链段发生膨胀，自由体积增大，扩散路径增多，扩散系数随着浓度的增加而增大。     

Study of He-induced nano-cavities as sinks of oxygen for forming silicon-on-insulator

In the present work, a Cz-Silicon wafer is implanted with helium ions to produce a buried porous layer, and then thermally annealed in a dry oxygen atmosphere to make oxygen transport into the cavities. The formation of the buried oxide layer in the case of internal oxidation （ITOX） of the buried porous layer of cavities in the silicon sample is studied by positron beam annihilation （PBA）. The cavities are formed by 15 keV He implantation at a fluence of 2×10^16 cm^-2 and followed by thermal annealing at 673 K for 30 min in vacuum. The internal oxidation is carried out at temperatures ranging from 1073 to 1473 K for 2 h in a dry oxygen atmosphere. The layered structures evolved in the silicon are detected by using the PBA and the thicknesses of their layers and nature are also investigated. It is found that rather high temperatures must be chosen to establish a sufficient flux of oxygen into the cavity layer. On the other hand high temperatures lead to coarsening the cavities and removing the cavity layer finally.     

高电荷态离子126Xeq+引起GaN表面形貌变化研究

用不同电荷态的126Xeq+离子(9≤q≤30)在室温下轰击GaN晶体表面,经原子力显微镜分析表明,当q>18,辐照区域由隆起转为显著的刻蚀.被轰击后的GaN晶体表面形貌主要取决于入射离子的电荷态.同时,样品表面形貌还与入射离子的剂量和入射角有关;在实验参数范围,与入射离子的初动能没有明显关系(180 keV≤Ek≤600 keV).当入射离子的电荷态q=18,与样品表面法线成60°角倾斜入射和垂直表面入射时,样品的表面几乎没有变化,只是倾斜入射后有很微小的隆起;当q＜18时,样品表面膨胀隆起,粗糙度增强,倾斜入射时表面隆起比垂直入射时更明显,而且都有清晰的峰状分界区;当q＞18时,样品表面被蚀刻呈凹陷状,有明显的齿状刻痕,且侵蚀深度与离子剂量近似呈线性关系,倾斜入射时的刻蚀深度大于垂直入射时的刻蚀深度.     

高能238U离子辐照AlN 晶体薄膜的光学特性研究

通过傅里叶变换红外光谱、拉曼光谱和光致发光谱测试手段分析了由HIRFL 提供的高能238U离子辐照AlN 晶体薄膜的光学特性变化。辐照后出现了A1(To),A1(Lo),E1(To) 和E2 等声子振动吸收模式,并且辐照使其在样品近表面Al—N 等振动模式遭到破坏后悬空的Al— 键很快与空气中的O离子发生结合,形成了Al—O 键。综合分析得出了蓝光发射带是与O 离子相关的VAl-ON-3N 和VAl-2ON-2N两种类型缺陷以及F-型缺陷聚合所致;绿光发射带是由基底中Al 原子产生的价带之间的跃迁所致。AlN thin film irradiated with 100 MeV 238U ions delivered from HIRFL (Heavy Ion Research Facility in Lanzhou) were investigated by Fourier Transform Infrared spectra, Raman spectra and Photoluminescence spectra. Phonon vibration absorption modes including A1(To), A1(Lo), E1(To) and E2 appeared in the irradiated samples. The irradiation made the Al—N bonds broken and the formation of Al—dangling bonds, which combined soon with oxygen atoms existing in air to form Al—O bonds. Blue light emission band are related to the two types of defects of VAl-ON-3N and VAl-2ON-2N and F-type defects aggregation. Green light emission band is due to energy transition among valence band of Al atoms in sapphire substrate.