Laser induced copper electroless plating on polyimide with Q-switch Nd:YAG laser

The results of laser induced deposition of copper on polyimide substrate from copper electrolyte solution are reported. Unlike most work reported in the literatures where CW Ar⁺ lasers were used, a second harmonic (532 nm wavelength) Q-switch Nd:YAG laser was used for our experiments. The deposition process was conducted by laser-catalyzing of the polyimide surface and subsequent photothermal-accelerated reduction of copper-complex ions in an alkaline reducing environment. The characteristics of the deposited copper line were investigated in terms of laser beam scanning speed, and the number of scans. The surface morphology and chemical composition of the deposited copper were analyzed using field emission scanning electron microscope (FESEM) and energy dispersive spectrometer (EDX). The optimum processing conditions have been identified. The copper deposit was found to adhere well to the substrate.     

Cosmic dust and our origins

The small solid particles in the space between the stars provide the surfaces for the production of many simple and complex molecules. Processes involving the effects of ultraviolet irradiation of the thin (hundredth micron) mantles are shown to produce a wide range of molecules and ions also seen in comets. Some of the more complex ones inferred from laboratory experiments are expected to play an important role in the origin of life. An outline of the chemical evolution of interstellar dust as observed and as studied in the laboratory is presented. Observations of comets are shown to provide substantial evidence for their being fluffy aggregates of interstellar dust as it was in the protosolar nebula, i.e. the interstellar cloud which collapsed to form the solar system. The theory that comets may have brought the progenitors of life to the earth is summarized.     

等离子辅助镀膜技术

传统的电子束蒸发工艺提供了高速率的沉积，但由于成膜分子的能量较低，使沉积的薄膜排列密度很低，其性能和块材料区别很大，已有不少学者发现了很多金属和氧化物薄膜具有典型的柱状结构，薄膜的低排列密度造成了其光学常数和机械性能不如块状材料，近几年发展起来的高功率等离子体辅助镀膜技术解决了上述问题，本文报道了我国自己研制的等离子体源（GIS）的性能指标，用这个源所做的单层TiO2膜的成膜工艺与质量，以及用等离子辅助沉积的减反射膜的工艺。     

不同入射角度下强流脉冲电子束能量沉积剖面和束流传输系数模拟计算

 强流脉冲电子束在材料中的能量沉积剖面、能量沉积系数和束流传输系数受其入射角的影响很大，理论计算了0.5~2.0MeV的电子束以不同的入射角在Al材料中的能量沉积剖面和能量沉积系数，并且还计算了0.4~1.4MeV电子束以不同入射角穿透不同厚度C靶的束流传输系数。计算结果表明，随着入射角的增大，靶材表面层单位质量中沉积的能量增大，电子在靶材料中穿透深度减小，能量沉积系数减小，相应的束流传输系数也减小；能量为0.5~2.0MeV的电子束当入射角在60°~70°时在材料表面层单位质量中沉积的能量较大。     

Pre- and post-breakdown electrical studies in ultrathin Al2O3 films by conductive atomic force microscopy

The loss of local dielectric integrity in ultrathin Al₂O₃ films grown by atomic layer deposition is investigated using conducting atomic force microscopy. I–V spectra acquired at different regions of the samples by constant and ramping voltage stress are analyzed for their pre- and post-breakdown signatures. Based on these observations, the thickness dependent dielectric reliability and failure mechanism are discussed. Our results show that remarkable enhancement in breakdown electric field as high as 130 MV/cm is observed for ultrathin films of thickness less than 1 nm.     

碳纳米管氧化成环制备研究

采用化学气相沉积方法制备的碳纳米管，用酸溶液进行弱氧化处理，经适当温度在大气中烧 灼后碳纳米管发生弯曲，在样品中出现大量的环状结构. 利用原子力显微镜、透射电子显微 镜和扫描电子显微镜对典型环直径为300 nm的碳纳米管环进行了表征. 烧灼温度和烧灼时间 对环的结构和产率有重要的影响. 实验数据统计结果表明，烧灼温度在510—530℃区间内 可得到超过40%的碳纳米管环产率，并且烧灼时间延长到120 min有利于提高碳纳米管环的产 率. 在加热情况下，碳纳米管端结合的羧基官能团脱水成酯，导致弯曲的碳纳米管结合成环 . 关键词： 碳纳米管环 化学气相沉积     

直流磁控溅射沉积含He钛膜的研究

研究了用He/Ar混合溅射气体的直流磁控溅射制备钛膜中，He的掺入现象.分析结果表明，大量的He原子（He/Ti原子比高达56%）被均匀地引入到Ti膜中，其He含量可由混合溅射气体的He分量精确控制.通过调节溅射参数，可实现样品中He的低损伤引入.研究还发现，溅射沉积的含氦Ti膜具有较高的He成泡剂量和高的固He能力，这可能是溅射沉积形成了纳米晶Ti膜所致.纳米晶Ti膜较粗晶材料具有很高浓度的He捕陷中心，使He泡密度增大而泡尺寸减小.随He引入量的增加，Ti膜的晶粒尺寸减小，He引起的晶体点阵参数和X射线衍射峰宽度增大，晶体的无序程度增加.Helium trapping in the Ti films deposited by DC magnetron sputtering with a He/Ar mixture was studied. He atoms with a surprisingly high concentration (He/Ti atomic ratio is as high as 56%)incorporate evenly in deposited film. The trapped amount of He can be controlled by the helium partial amount. The introduction of the helium with no extra damage(or very low damage) can be realized by choosing suitable deposition conditions. It was also found that because of the formation of nanophase Ti film a relative high He flux for bubble formation is needed and the amount of the retain He in sputtering Ti films is much higher than that in the coarse grain Ti films. The nanophase Ti film can accommodate larger concentration of trapped sites to He, which results in a high density and small size of the He bubbles. With the increasing He irradiation flux, the grain size of Ti film decreases and the lattice spacing and width of the X ray diffraction peak increase due to the He introduction, and the film tends to amorphous phase.     

Charge ordering modulations in a Bi_0.4Ca_0.6MnO₃ film with a thickness of 110 nm

The low temperature sample stage in a transmission electron microscope is used to investigate the charge ordering behaviours in a Bi 0.4 Ca 0.6 MnO 3 film with a thickness of 110 nm at 103 K.Six different types of superlattice structures are observed using the selected-area electron diffraction(SAED) technique,while three of them match well with the modulation stripes in high-resolution transmission electron microscopy(HRTEM) images.It is found that the modulation periodicity and direction are completely different in the region close to the Bi 0.4 Ca 0.6 MnO 3 /SrTiO 3 interface from those in the region a little further from the Bi 0.4 Ca 0.6 MnO 3 /SrTiO 3 interface,and the possible reasons for this are discussed.Based on the experimental results,structural models are proposed for these localized modulated structures.     

真空紫外波段铝反射膜制备

为制备出在130～210nm波段具有良好光谱性能的铝反射膜,优化设计了铝反射镜中铝层和保护层氟化镁的厚度,理论确定铝层和氟化镁保护层最佳厚度分别为80nm和33nm。采用热舟蒸发工艺,在BK7基片上制备了Al反射膜样品,获得了130～210nm波长范围内反射率均大于80%的金属铝膜。研究了铝层沉积速率和紫外辐照处理对薄膜性能的影响,并考察了铝膜光谱性能的时效性。结果表明铝层沉积速率越快,制备的铝膜反射率越高;合理地存放铝膜元件,可以长时间内保持铝膜的光谱性能。适当的紫外辐照处理能进一步提高铝膜在真空紫外波段的反射率。     

可见光区大角度减反射光学薄膜制备工艺研究

为获得可见光波长范围的大角度减反射光学薄膜,采用电子束蒸发斜角蒸镀工艺,按照设计好的膜系,通过蒸镀一系列低折射率膜层,最终得到在380～780nm波长间,入射角0～70°,平均反射率低于1%的光学薄膜。实验结果表明利用斜角蒸镀工艺镀制出折射率从基底到空气的渐变多层膜结构以取得优良的减反射效果是可行的。