原位电子束诱导沉积制备碳纳米结构

以多壁碳纳米管为基本材料,利用电子束诱导沉积的方法进行了纳米结构加工、修饰研究.电子束诱导沉积实现了二个碳纳米管端部之间的牢固焊接,实现了纳米材料间的几乎无损伤连接.原位测量表明多壁碳纳米管间的连接为欧姆接触.进一步对碳纳米管施加外电场可以使端部碳原子间的π键打开,外部碳原子经电子束诱导沉积在碳纳米管的端部,并定向生长成非晶态碳纳米线.由于碳纳米管和纳米线结合处的.键作为绝缘界面,形成了电子输运的势垒,所得到的碳纳米管-纳米线复合结构具有整流特性.利用电子显微镜进行纳米材料的结构加工、修饰,具有选择位置精确、可实时监测、对纳米材料几乎无损伤、重复性和可靠性高,以及加工尺度可人为控制的特点.     

聚焦电子束辐照诱导喷金SiOx纳米线新型结构加工

在纳米加工技术中,利用透射电子显微镜(TEM)中的电子束辐照诱导低维纳米材料制备异质结构的加工方式因具有广阔的应用前景而备受瞩目.利用成熟的聚焦电子束原位辐照技术,通过改变电子束辐照时的强度和位置对喷金非晶SiOx纳米线进行原位辐照,诱导其结构发生变化,从而实现结构加工.实验结果显示,当束斑直径大于纳米线直径的聚焦电子...     

超精细纳米结构加工技术

利用高能会聚电子束的辐照损伤能力,在300 kV高分辨透射电镜中成功加工出小于5 nm的超精细纳米结构.加工精度在特征尺寸和空间位置上可同时达到一个纳米.加工的纳米结构具有原子尺度的边界,并可以通过高分辨像直接监视纳米结构的形成过程.这种技术可以广泛应用于各种无机材料,尤其适用于无机化合物.结合自动控制,这种技术可以用于加工任意复杂的二维纳米结构.     

运用精确电压衬度像技术实现精确定位的原位电子束纳米刻蚀：制造具有悬挂纳米线结构的纳米器件

本文演示了运用精确电压衬度像技术实现原位电子束纳米刻蚀技术的精确定位,并运用该技术制作成具有悬挂结构的纳米开关。通过运用精确电压衬度像定位技术,能够很好地控制偏转电极的定位,误差可减少到大约10nm。通过该技术,不用通过任何刻蚀过程只运用一次电子束纳米刻蚀,便可实现将分散的纳米线夹在两个电阻层中间形成悬挂结构。在原位电子束刻蚀的整个过程中,无需移动样品台从而消除了样品台的移动误差。因此,整个过程中不需要高精确的激光台和定位标记,从而简化了传统的电子束纳米刻蚀工艺。通过该方法制作的纳米开关随着施加电压的改变很好地实现了闭合和断开的状态。这种简化的过程提供了一种简单、低成本、快速的通过改装过的场发射扫描电子显微镜（FESEM）来制作纳米线悬挂结构的方法,并可运用该技术进一步制造多层结构和特殊的纳米器件。     

基于硅模具制作的纳米裂纹及应变传感器

纳米裂纹制造技术作为一种非传统的纳米加工技术被应用于纳米线条、纳流控芯片和传感器等众多研究领域,然而纳米裂纹生成的随机性及其图案的不确定性限制了该项技术的发展.利用硅模具以及二次倒模工艺,在聚二甲基硅氧烷(PDMS)基底表面制作相互平行且分布均匀的金纳米裂纹.硅模具上带有利用硅各向异性腐蚀工艺加工出的V型沟槽结构,通过...     

硅纳米线纳米电子器件及其制备技术

硅纳米线由于特殊的光学及电学性能如量子限制效应及库仑阻塞效应等,在纳米电子器件的应用方面具有潜在的发展前景。介绍了采用电子束蚀刻技术(EB)、反应性离子蚀刻技术(RIE)、金属有机物化学气相沉积(MOCVD)等制备技术及场效应晶体管、单电子探测器及存储器、双方向电子泵及双重门电路等硅纳米线纳米电子器件的最新进展情况,并对其发展前景作了展望。     

由纳米棒和纳米叶组成的铁磁性的MnSb薄膜

提供了一种利用物理蒸发沉积技术在单晶硅上生长纳米尺度的MnSb薄膜的方法.X射线衍射分析表明薄膜的主要成分是MnSb合金.场发射扫描电镜观察到薄膜是由纳米尺寸的棒状物和叶状物组成.纳米棒的平均直径为20nm,长度在几百纳米范围内.纳米叶的厚度大约为20nm,宽度为100nm左右.用可变梯度磁力计测量了薄膜的磁滞回线,结果显示薄膜有很强的几何各向异性.     

基于纳米操作的纳米线钎焊结构组装及互连

近年来,纳米线在纳米电子学、纳米光子学、纳米医学和纳米机电系统等领域的应用逐渐广泛,纳米线的连接已经成为未来器件小型化和集成化的关键问题。为了实现良好的纳米线互连,提出了一种基于扫描电子显微镜(SEM)的纳米线-纳米钎料原位互连结构组装、钎焊互连的方法。利用开发的SEM纳米操作平台,实现了直径为100 nm左右的ZnO纳米线与直径为180～300 nm的Ag纳米钎料的同基底互连结构组装。利用SEM聚焦电子束辐照熔融纳米钎料实现了纳米线钎焊互连,利用双探针纳米操作系统对焊接后的纳米线进行电流-电压(I-V)测试,钎焊后的纳米互连结构成功实现电流导通。     

电子束纳米光刻技术研究

纳米光刻技术在微电子制作中起着关键作用,而电子束光刻在纳米光刻技术制作中是最好的方法之一.我们使用VB5电子束曝光系统,经过工艺研究,现已研究出最细分辨率剥离金属条为17nm,最小剥离电极间距为10nm,最细T型栅为100nm.     

电子束光刻在纳米加工及器件制备中的应用

电子束光刻技术是推动微米电子学和微纳米加工发展的关键技术,尤其在纳米制造领域中起着不可替代的作用。介绍了中国科学院微电子研究所拥有JEOLJBX5000LS、JBX6300FS纳米电子束光刻系统和电子显微镜系统的电子束光刻技术实验室,利用电子束直写系统所开展的纳米器件和纳米结构制造工艺技术方面的研究。重点阐述了如何利用电子束直写技术实现纳米器件和纳米结构的电子束光刻。针对电子束光刻效率低和电子束光刻邻近效应等问题所采取的措施;采用无宽度线曝光技术和高分辨率、高反差、低灵敏度电子抗蚀剂相结合实现电子束纳米尺度光刻以及采用电子束光刻与X射线曝光相结合的技术实现高高宽比的纳米尺度结构的加工等具体工艺技术问题展开讨论。     

Hierarchically Ordered Arrays of Noncircular Silicon Nanowires Featured by Holographic Lithography Toward a High‐Fidelity Sensing Platform

A novel, highly uniform and tunable hybrid plasmonic array is created via ion‐milling, catalytic wet‐etching and electron‐beam evaporation, using a holographically featured structure as a milling mask. A simple and low‐cost prism holographic lithography (HL) technique is applied to create an unprecedentedly coordinated array of elliptic gold (Au) holes, which act as the silicon (Si) etching catalyst in the reaction solution used to fabricate an elliptic silicon nanowire (SiNW) array; here, the SiNWs are arrayed hierarchically in such a way that three SiNWs are triangularly coordinated, and the triangles are arranged hexagonally. After removing the polymeric mask and metal thin film, the highly anisotropic thick Au film is deposited on the SiNW arrays. This hybrid substrate shows tunable optical properties in the near‐infrared (NIR) region from 875 nm to 1030 nm and surface‐enhanced Raman scattering (SERS) activities; these characteristics depend on the catalytic wet etching time, which changes the size of the vertical gap between the Au thick films deposited separately on the SiNWs. In addition, lateral interparticle coupling induces highly intensified SERS signals with good homogeneity. Finally, the Au‐capped elliptical SiNW arrays can be hierarchically patterned by combining prism HL and conventional photolithography, and the highly enhanced fluorescence intensity associated with both the structural effects and the plasmon resonances is investigated.     

Simulation of Carrier Trapping in an Embedded Nanowire and Its Effect in the Nano-EBIC Technique

Semiconductors - Effect of an isolated Ge nanowire embedded in an n-doped Si on electron beam induced current is simulated by a Monte Carlo calculation algorithm. A circular nano-contact is used to...     

A combined objective lens for electrons and ions

Nanofabrication is possible using focused ion beam technology, but the observation of these structures with the same ion beam is not possible because of its erosion effect. Therefore a general purpose instrument for nanotechnology based on particle optics has to combine an ion and an electron beam. The objective lens, the final lens above the specimen, has to focus both beams on the specimen. An objective lens that combines magnetic and electrostatic fields has been designed for this purpose. Its aberration coefficients allow a 1 nm ion beam and a 0.3 nm electron beam.     

The Features of GaAs Nanowire SEM Images

The detailed study of GaAs nanowires synthesized by molecular beam epitaxy performed by scanning electron microscopy allowed to reveal the presence of specific contrast in the images obtained. To understand the causes of the phenomenon the transmission electron microscopy of nanowire crystal structure was carried out. The results showed that it could be caused by the segments having polytypic crystal phase. It was also confirmed by the modelling of the electron beam scattering on such nanowire arrays.     

Specimen preparation for high-resolution transmission electron microscopy using focused ion beam and Ar ion milling

We have developed a focused ion beam (FIB)-Ar ion-milling technique for high-resolution transmission electron microscopy. A micrometresized specimen was mounted on a cross section of metal foil of a few micrometres thick, using FIB microsampling. Following this, a 2 degrees wedgeshaped part was made in the specimen using FIB. Finally, the specimen was milled using an Ar ion beam to remove the FIB-damaged layers. We applied the FIB-Ar ion milling technique to a CeO(2)/Gd(2)Zr(2)O(7) multilayer specimen, resulting in the crystal lattice fringes of both layers being clearly observable in comparison to a specimen finished using a Ga ion beam at an accelerating voltage of 10 kV.     

Photoluminescence Properties of a Nearly Intrinsic Single InN Nanowire

In this paper, the achievement of nearly intrinsic InN nanowire is reported. With the use of an in situ deposited In seeding layer, nearly defect‐free, non‐tapered InN nanowires are grown directly on Si(111) substrates by molecular beam epitaxy. The photoluminescence emission of a single InN nanowire is analyzed, which exhibits, for the first time, a very narrow (～13 meV) spectral linewidth, a clear band filling effect with the increase of excitation power, and a significant red shift of the peak energy with increasing temperature. Detailed analysis confirms the InN nanowire has a very low residual doping of ～1 × 10¹⁶ cm^?3, or less. It is further suggested that there is a small, or negligible level of electron accumulation at the lateral nonpolar surfaces of nearly intrinsic InN nanowires, which is in direct contrast to the commonly observed surface electron accumulation of n‐type degenerate InN.     

Solution-processed polymer–silver nanowire top electrodes for inverted semi-transparent solar cells

We present a transparent, fully solution-processed top anode system comprising a thin, conductive polymer interlayer below a silver nanowire mesh for efficient organic electronic devices. We fabricate inverted semi-transparent polymer solar cells exhibiting power conversion efficiencies that are comparable to devices incorporating an opaque electrode. By means of scanning electron microscopy and light beam induced photocurrent measurements we show that the thin polymer interlayer facilitates charge extraction from the active layer and efficient transport to the metallic nanowire mesh.     

Four-Wire Resistance Measurements of a Bismuth Nanowire Encased in a Quartz Template Utilizing Focused Ion Beam Processing

Four-wire resistance measurements were performed using a bismuth nanowire, 750?nm in diameter, 1.96?mm in length, and encapsulated in a quartz template. One side of the quartz template was polished to allow focused ion beam (FIB) processing, and metal film layers were deposited on the polished side to form electrodes. Nanofabrication was employed to remove a selected portion of the quartz, and FIB processing was used to expose the surface of the bismuth nanowire. A local area of the bismuth wire was successfully exposed, and a carbon electrode was deposited on the bismuth wire in?situ by a chemical reaction between the ion beam and phenanthrene gas. Additional carbon deposition on the initial carbon electrode was used to connect to a metal film on the quartz template. In total, four nanofabrications were performed on the bismuth wire to create the desired electrical contacts. The resistivity of the nanowire was measured by a four-wire method to be 1.29??????m at 300?K, corresponding to that of bulk bismuth. The temperature dependence of the resistivity was also measured, and was qualitatively and quantitatively in good agreement with previous calculated and experimental results using other bismuth nanowires. The present results demonstrate the successful development of a technique to fabricate an electrode on a local area of a nanowire using FIB processing to form suitable electrical contacts.     

A method for multidirectional TEM observation of a specific site at atomic resolution

A new technique has been developed for the three-dimensional structure characterisation of a specific site at atomic resolution. In this technique, a focused ion beam (FIB) system is used to extract a specimen from a desired site as well as to fabricate the electron transparent specimen. A specimen holder with a specimen stage rotation mechanism has also been developed for use with both an FIB system and a high-resolution transmission electron microscope (TEM). The specimen holder allows both the FIB milling of a specimen and its observation in TEM without remounting the specimen from the specimen holder. A specimen for the three-dimensional TEM observation is extracted using the FIB micro-sampling technique and shaped into a pillar to mount on a tip of a needle stub enabling a multidirectional observation. The technique was applied to the multidirectional observation of the crystal structure of an Si single crystal at atomic resolution. The crystal lattice fringes of the two Si(111) planes with distances of 0.31 nm as well as the lattice fringes of the Si(200) with distances of 0.19 nm were clearly observed.     

3D real-space quantum transport simulation of nanowire MOS transistors: Influence of the ionized doping impurity

We report a numerical study of both donor- and acceptor doping impurity effects in the quantum transport of silicon nanowire metal-oxide-semiconductor (MOS) transistors. The code is based on a full three-dimensional (3D) real-space non-equilibrium green function (NEGF) formalism self-consistently coupled with the 3D Poisson equation. The general results show that the influence of an impurity strongly depends on its type. Indeed, an acceptor or a donor will create a repulsive or attractive potential, giving rise to tunneling effect or resonances, respectively. Our calculations analyze the impact on electron density, transmission coefficient and drain current (I_D) which undergoes variations up to 50%. This pinpoints the importance of intrinsic fluctuations due to doping in ultimate nano-transistors whose magnitude cannot be neglected in the next generations of integrated circuits.