矩底拱面状微透镜阵列的氩离子束刻蚀

在ＺｒＯ２、ＩｎＰ、Ｓｉ及ＳｉＯ２即融凝石英衬底上用氩离子束刻蚀制作面阵矩底拱面状微透镜阵列，给出了氩离子束在不同的入射角度下刻蚀器件的速率与离子束能量之间的关系。实验表明，用国产ＢＰ２１２紫外正型光刻胶制作的光致抗蚀剂掩膜图形在经过优化的工艺条件下可以通过氩离子束刻蚀将预定图形转移到衬底材料中。     

微透镜制作中光刻胶与衬底匹配行为的研究

利用光刻/离子束刻蚀制作大面阵硅微透镜阵列,采用SEM和表面探针测试等手段分析所制样品的形貌特点,定性讨论制备工艺的不同对所制器件的影响.所用工艺为大面阵微尖阵列和微合阵列的离子束刻蚀制作奠定了基础.     

矩底拱面状微透镜阵列的氩离子束刻蚀 

 在ZrO₂、InP、Si及SiO₂即融凝石英衬底上用氩离子束刻蚀制作面阵矩底拱面状微透镜阵列，给出了氩离子束在不同的入射角度下刻蚀器件的速率与离子束能量之间的关系。实验表明，用国产BP212 紫外正型光刻胶制作的光致抗蚀剂掩膜图形在经过优化的工艺条件下可以通过氩离子束刻蚀将预定图形转移到衬底材料中。     

聚焦离子束研制半导体材料光子晶体

介绍了利用聚焦离子束设备在多种半导体材料上成功研制的近红外波段二维光子晶体，给出了相关微加工结果，发现微加工的尺寸和理论设计尺寸相吻合；测试了所加工的无源光子晶体光子带隙和有源光子晶体的发光谱. 实验证明聚焦离子束可以研制二维光子晶体及相关光子晶体器件. 关键词： 聚焦离子束 半导体材料 光子晶体     

FIB快速加工纳米孔点阵的新方法

纳米尺度的点阵在纳米器件和基础科学研究方面都具有非常重要的应用.目前普遍采用的聚焦离子束和电子束曝光技术可以很方便的在衬底上加工纳米量级的微细结构，但大面积的图形加工过程需要花费太多的机时.介绍一种利用设计图形BMP文件的像素点阵和实际加工区域之间的匹配关系，通过聚焦离子束加工获得所需要的纳米孔点阵的新方法.采用这种方法可以在短时间内获得大面积的纳米点阵结构. 关键词： 聚焦离子束 电子束曝光 纳米孔点阵     

Ar+离子束刻蚀制作凸面闪耀光栅

凸面闪耀光栅是研制高光谱分辨率超光谱成像系统的关键器件之一.由于要求的闪耀角度一般较小,制作工艺难度大,其衍射效率与理论值有较大差距,一直制约其应用.针对上述问题与难点进行了分析,通过光刻胶光栅掩模制作和Ar<'+>离子束刻蚀等工艺制作了凸面闪耀光栅.针对离子束大掠入射刻蚀凸球面时槽形闪耀角不易一致的难题,利用转动扫描...     

利用Monte Carlo法计算粒子传输中的空间电荷效应

在电子束印刷(electron-beam lithography)、聚焦离子束(focus ion beam)以及阴极射线管(cathode ray tube)等电子及离子束器件中,束中各粒子之间存在相互作用,产生空间电荷效应。人们对电子及离子束器件中的空间电荷效应已经做了大量的研究。到目前为止,通常采用Monte Carlo法计算粒子输运过程中的离散的空间电荷效应。在此主要研究在束形成区利用Monte Carlo法计算空间电荷效应,并讨论在计算过程中出现的边缘效应,在此基础上提出一些新的处理方法以减小边缘效应,提高计算效率。     

北京HI-13串列加速器上单粒子效应辐射装置简介

在北京HI-13串列加速器上建立了微电子器件单粒子效应地面模拟辐照试验装置. 利用Q3D磁谱仪的高分辨特性和散焦特性, 获得了强度均匀分布、注量率可调的单能重离子束流, 开展了大量星用器件抗单粒子效应性能评估试验研究. 为了深入研究单粒子效应机制, 采用针孔准直技术, 建立了重离子微束单粒子效应辐射装置, 获得了最小束点尺度为2.3μm×3.5μm的重离子微束.     

快离子束光谱学介绍

一引言 传统的光谱学,由于光源技术的局限,半个世纪以来受到了很大的限制.自从可调频激光技术引人光谱学,以及快离子束光源用作研究高离化态和多重激发态的新型光源之后,古老的光谱学又获得了新生. 快离子束光源包括束箔、束-气体和束-激光光源三种形式.它们是让由加速器加速的离子束分别穿过一个固体薄箔、气体池或激光束来使离子束中的离子激发,从而在以后的飞行路程中退激发光的.用它们作为光源来研究原子和分子结构的光谱学方法称为快离子束光谱学.由于光源的激发机制不同,与传统的光谱学相比,快离子束光谱学具有以下几个突出的特点: (1…     

利用离子束制成纳米尺寸的构件

激光在光刻方面正日益得到广泛的应用 ,但是 ,用在光刻方面的激光设备对于纳米尺寸构件的制作来说 ,因其系统太粗糙而变得无能为力 .最近 ,日本科学家利用聚焦的离子束制成了纳米尺寸的构件 .利用这种技术制成了线径只有 80ｎｍ的微型弹簧和壁厚为亚微米、外径为 2 75 μｍ的深红色玻璃制品等 .预计这种技术将有可能用来制作光通信的高质量控制元件 .在这种技术中 ,用的是镓离子束 .加速电压为30ｋＶ时 ,离子束的直径可聚焦到 7ｎｍ ,其位移可精确地控制到 1ｎｍ .当镓离子束通过气态芳香氢氧化物加速时 ,氧化物减少 ,碳便积聚起来 .硅片在…     

γ射线辐照下多壁碳纳米管结构转变过程研究

采用60Coγ射线辐照纯净的多壁碳纳米管,用高分辨透射电镜和拉曼光谱,研究了多壁碳纳米管由石墨结构向无定形结构转变的演化过程.发现在γ射线辐照下,碳纳米管的外部石墨层逐渐失去最初的有序结构而向无定形结构转变.而且,随着γ射线辐照剂量的增加,无定形结构不断推进,而石墨层结构则不断减小,直至使整个碳纳米管变为一个中空的无定形纳米线结构.用原子位移理论和溅射机理对这种转变过程进行了分析.γ射线轰击碳纳米管击出碳原子,碳原子停留在晶格的间隙位置上产生间隙原子,在它原来的平衡位置则留下一个空位.当轰击粒子动能足够大时导致碰撞级联效应,无序结构增加.多数空位和间隙原子可能相互复合而彼此退火,但仍有少数原子作为间隙原子而造成晶格进一步缺陷.辐射也可以引起碳原子的溅射,溅射出来的碳原子沉积在碳纳米管的外壁上形成一层无定形碳结构.     

掺氢、掺氮碳纳米线的合成及其焊接

利用一种有效而别致的双离子(N⁺和Ar⁺)辐照和热处理技术合成并焊接无定形碳纳米线(ACNWs).实验样品用高分辨透射电子显微镜(HRTEM)进行了表征证实,适当搭配的双离子辐照与热处理的结合将会引起多壁碳纳米管无定形化并导致相互交叉纳米线的焊接.此外碳结构相变中的原子演化也在目前已有的概念基础上进行了简单地讨论. 关键词： 无定形碳纳米线 相变 透射电子显微镜     

多壁碳纳米管在循环相变过程中结构变化初探

对由离子束辐照多壁碳纳米管（MWCNTs）产生的无定形碳纳米线（ACNWs）进行了高温退火（2400℃）处理，通过透射电子显微镜(TEM)观察发现，ACNWs体部转变成与原来MWCNTs相似 的管状石墨结构，而其封端区域的石墨晶体结构形态却与原来的MWCNTs完全不同，且变化多 端.基于实验结果，对其相变过程机理提出了一个概念性的模型. 关键词： 无定形碳纳米线 高温退火 相变 透射电子显微镜     

超长定向含铁多壁碳纳米管阵列的制备

采用无模板化学气相沉积法,以二茂铁为催化剂,二甲苯为碳源,利用单温炉加热装置制备了定向碳纳米管阵列。运用扫描电子显微镜、透射电子显微镜、拉曼光谱和X射线衍射仪等对定向碳纳米管阵列的形貌、成分和物相进行细致的分析和表征。结果表明:制得的碳纳米管阵列具有良好的定向性和多壁管状结构,并且石墨化程度高;碳纳米管中除碳元素外,管中包含有少量以纳米颗粒和纳米线形式存在的铁及其化合物,主要成分是铁和碳化铁。结合碳纳米管的制备和透射电子显微镜分析表征结果,认为超长碳纳米管阵列的生长模式为底部生长方式,即经历催化剂分解、催化、成核、长大、中毒、凝聚成粒和连接成线的循环过程,正是由于碳源和催化剂的连续供应促成了碳纳米管阵列的快速定向生长。     

Effects of different carbon precursors on synthesis of multiwall carbon nanotubes: Purification and Functionalization

Cyclohexanol and xylene were used as carbon precursors, for synthesis of multiwall carbon nanotubes (MWCNTs) arrays in a CVD system at temperature of 750 °C, using nitrogen as carrier gas and ferrocene as catalyst. Different characterization methods were employed to compare the MWCNTs structure synthesized by these two precursors. All scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA) and Raman spectroscopy results illustrated that using cyclohexanol could significantly reduce formation of amorphous carbon and catalyst particles in the as-grown CNTs. The less amorphous carbon can be attributed to in situ oxidation in presence of oxygen atom of cyclohexanol. Characterizations showed that MWCNTs with high purity could be obtained using cyclohexanol as carbon precursor. The as-grown MWCNTs were purified by oxidation and acid treatment. Characterization of the purified MWCNTs using HNO₃/H₂SO₄ (1/3 or 1/1), 8 M HCl or 8 M HNO₃ was carried out. The results showed that 8 M HNO₃ could be considered as the best chemical to obtain more pure MWCNTs, less amorphous and metal particles and less damaged MWCNTs. The Raman spectroscopy results demonstrated that HNO₃/H₂SO₄ (1/3) treatment could more disorder the MWCNTs structure and this was attributed to the bigger destroying effect of this acid treatment. Furthermore, the TEM analysis of MWCNTs before and after acid treatment revealed that acid treatment could remove encapsulated catalyst particles. The FTIR analysis illustrated that purification of the MWCNTs with nitric acid could connect the functional groups onto the outer surface of MWCNTs and this resulted in more dispersion of the MWCNTs in water.     

碳纳米管的氧化铝模板法合成及其退火效应研究

结合氧化铝模板制约生长技术和高温退火处理，得到了相当统一的多壁碳纳米管.扫描电子显微镜（SEM）图像表明模板制约生长的初始碳纳米管形貌和尺寸完全受控于模板结构，透 射电子显微镜（TEM）和x射线粉末衍射（XRD）结果显示其管壁结构为无定形碳和石墨纳米 晶组成的混杂结构.为减少晶格缺陷及无定形碳，对初始碳纳米管进行系列高温（1100—240 0℃）退火处理，并初步研究了管壁在高温下的晶化行为.实验证明高温退火是提高多壁碳纳 米管质量的有效途径. 关键词： 氧化铝模板 碳纳米管 高温退火     

Controllable purification, cutting and unzipping of multi-walled carbon nanotubes with a microwave method

A rapid microwave-assisted method was developed for the purification, cutting and unzipping of arrays of multi-walled carbon nanotubes (MWCNTs) using a mixture of KMnO₄ and H₂SO₄. To harness the extent of treatment, MWCNT products were fully characterized at different reaction times by UV-visible and Raman spectroscopies as well as scanning and transmission electron microscopies. The results show that the carbon nanoparticles and the amorphous carbon which coated the MWCNTs were removed after about 10 minutes. The excessive oxidation of MWCNTs then leads to cutting and unzipping of graphitic walls. Moreover, while the catalyst residues outside the MWCNTs were rapidly extracted up to 10 minutes, the removal of catalyst residues inside the MWCNTs did not begin before 20 minutes. This method can be considered as an efficient route for the purification, cutting and unzipping of MWCNTs due to its fast and controllable procedure.     

Contact welding study of carbon nanotube with ZnO nanowire

Study of proton beam induced welding of multiwall carbon nanotubes (MWCNTs) with ZnO nanowires (NWs) has been carried out by proton (H⁺) beam irradiation. The samples were irradiated by 70-keV proton (H⁺) ion beams at different substrate temperatures. The irradiation-induced defects in CNTs and ZnO NWs were greatly reduced at elevated temperature. The crystalline structure of ZnO NWs and MWCNTs were found to remain stable after the irradiation at 700 K. As a preparation step, a coupling of two parallel ZnO NWs with irradiation has also been demonstrated. The welding mechanisms of MWCNTs and ZnO NWs were also been suggested. These two welding processes between same and distinct nanostructures to form homo- and hetero-junctions have provided an opportunity to mass produce interconnecting one-dimensional structures used for the manufacturing of future nanowire-based electronic circuits and devices.     

The effect of chemical treatment on the crystallinity of multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) were chemically treated using nitric acid solution for different time. Quantitative analysis of the crystallinity of the MWCNTs was performed by wide-angle X-ray diffraction (WAXD). The WAXD patterns were deconvoluted into the crystalline diffraction peaks and the amorphous scattering peaks. The introduction of a correction factor for the integrated peak intensity can enhance the computational accuracy of the crystallinity. With increasing the chemical treatment time, the crystallinity of MWCNTs first increases, and then decreases. When the chemical treatment time is equal to 2 h, the crystallinity of MWCNTs reaches the maximum of 85.9%. Moreover, the degree of order in the structures of chemically treated MWCNTs was further studied by thermogravimetric analysis (TGA) and high-resolution transmission electron microscopy (HRTEM). It was found that the external walls of chemically treated MWCNTs with high crystallinity consist of a series of perfectly continuous and straight graphite layers.     

Synthesis of carbon nanotubes by CVD: Effect of acetylene pressure on nanotubes characteristics

The effect of acetylene partial pressure on the structural and morphological properties of multi-walled carbon nanotubes (MWCNTs) synthesized by CVD on iron nanoparticles dispersed in a SiO₂ matrix as catalyst was investigated. The general growing conditions were: 110 cm³/min flow rate, 690 °C synthesis temperature, 180 Torr over pressure and two gas compositions: 2.5% and 10% C₂H₂/N₂. The catalyst and nanotubes were characterized by HR-TEM, SEM and DRX. TGA and DTA were also carried out to study degradation stages of synthesized CNTs. MWCNTs synthesized with low acetylene concentration are more regular and with a lower amount of amorphous carbon than those synthesized with a high concentration. During the synthesis of CNTs, amorphous carbon nanoparticles nucleate on the external wall of the nanotubes. At high acetylene concentration carbon nanoparticles grow, covering all CNTs’ surface, forming a compact coating. The combination of CNTs with this coating of amorphous carbon nanoparticles lead to a material with high decomposition temperature.