共查询到20条相似文献,搜索用时 156 毫秒
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气-液-固法(VLS)是目前生长各种准一维纳米结构的主要工艺技术.本文首先介绍了VLS的生长原理,然后以生长机制为主线,着重评论了近3-5年内它在ZnO、GaN、Si以及SiC等纳米线及其阵列合成中应用的某些新进展.最后提出了改进VLS方法的几项措施,并展望了它的今后发展趋势. 相似文献
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si纳米线及其阵列是近年内新发展起来的准一维半导体光电信息材料,在场效应器件、单电子存储器件、光探测器件、场发射器件、纳米传感器件和高效率发光器件以及集成技术中具有潜在的应用.本文以气-液-固(VLS)生长机制为主线,介绍与评论了近5年来Si纳米线在制备与合成技术方面所取得的一些最新进展.其主要内容包括Si纳米线的各种金属催化生长和氧化物辅助生长,最后指出了今后该研究的发展方向. 相似文献
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用VLS机制制备硅纳米线的生长阶段研究 总被引:2,自引:0,他引:2
在镀Ni的Si衬底上用硅烷高温分解的方法由VLS机制制备了硅纳米线,在不同的实验条件下研究了VLS机制生长的三个阶段:结晶阶段、共熔阶段和生长阶段,特殊条件下制备的处于结晶阶段的长度仅几十纳米的硅纳米线显示硅纳米线是从催化剂颗粒中长出来的,观察到的硅纳米线的生长过程说明VLS机制在纳米尺度仍然有效,可用于各种材料纳米线的制备。 相似文献
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Although carbon nanotubes (CNTs) with a variety of morphologies have been successfully synthesized, there is no clear physical picture of the growth process. Correspondingly, the growth mechanism is still not clear up to now. Here we suggest a VLS model for the growth process of CNTs, which involves a liquid or liquid-like state catalyst. The basic idea is that, due to the high thermal conductivity and nanometer size of the catalyst and the fast diffusion of carbon atoms in it, both the temperature and the carbon atom distribution across it are uniform. The supersaturation level can be expressed as a function of the carbon concentration and temperature, which determines the nucleation dynamics and growth kinetics. Based on this model, the growth rate equation was obtained to describe the growth kinetics of carbon nanotubes, which shows good accordance with the experimental results. 相似文献
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Periodically twinned nanowires and polytypic nanobelts of ZnS: The role of mass diffusion in vapor-liquid-solid growth 总被引:1,自引:0,他引:1
There are two mass diffusion processes regarding the vapor-liquid-solid (VLS) growth of nanostructures: one is inside the catalyst droplet toward the liquid-solid interface; the other is along the side surface planes of the growing nanostructures. In this letter, microscale, modulated mass diffusion scenarios are exhibited through the synthesis of two types of ZnS nanostructures in an Au-catalyzed VLS process: periodically twinned nanowires originated from periodical fluctuation between diffusion rate inside the catalytic droplet and the growth rate on the liquid-solid interface; the formation of asymmetrically polytypic nanobelts is related to one certain side surface bounded by high surface-energy plane, which serves as a preferential diffusion direction of reactant adatoms. The results may have important impact on the understanding of the physical and chemical process of the VLS mechanism. These longitudinally and latitudinally tunable crystalline structures enrich the family of one-dimensional nano-building blocks, and may find potential applications in nanotechnology. 相似文献
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Khac An Dao Tien Dai Nguyen Anh Tuan Phan Hung Manh Do 《Journal of Materials Science: Materials in Electronics》2013,24(7):2513-2520
The nanowires grown on GaAs semiconductor substrate play very important roles in nanoelectronics, optoelectronics, and sensors. The nanowires can be produced by many methods among the existing methods of nanowires growth on GaAs semiconductor, the vapor–liquid–solid (VLS) method appears to be simple, low cost, and popular. However, this method in practice requires further investigations concerning the growth mechanisms, size effects, and the role of Au catalyst metal diffusion, as well as the effect of technological conditions. Several undesired phenomena, which strongly influence the morphologies, features, and applications of the grown nanowires, can occur as the result of using thick Au catalyst layers, high growth temperatures, and/or small vapor volume in the closed ampoule. This paper aims to examine simultaneous formation of voids, etched holes, and GaO particles along with the nanowires grown by VLS method on GaAs substrate. As the result, typical technological conditions for the nanowires growth with better characterizations are proposed. 相似文献
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合成陨硫铁表面的炭丝和炭球 总被引:1,自引:0,他引:1
采用电弧放电蒸发和沉淀技术,使用石墨和黄铁矿为原料,在合成的陨硫铁球粒表面发现有空心球体和丝状物质。经SEM、TEM和EDX的研究,证实它们是纳米级的炭球和炭丝。讨论了用电弧放电法合成陨硫铁过程中,天然矿物黄铁矿对炭丝、炭球和纳米碳管形成的催化作用及其关系 相似文献
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We report on the catalytic growth of thin carbon sheathed single crystal germanium nanowires (GeNWs), which can solve the obstacles that have disturbed a wide range of applications of GeNWs. Single crystal Ge NW core and amorphous carbon sheath are simultaneously grown via vapor-liquid-solid (VLS) process. The carbon sheath completely blocks unintentional vapor deposition on NW surface, thus ensuring highly uniform diameter, dopant distribution, and electrical conductivity along the entire NW length. Furthermore, the sheath not only inhibits metal diffusion but also improves the chemical stability of GeNWs at even high temperatures. 相似文献
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For advanced device applications, increasing the compositional abruptness of axial heterostructured and modulation doped nanowires is critical for optimizing performance. For nanowires grown from metal catalysts, the transition region width is dictated by the solute solubility within the catalyst. For example, as a result of the relatively high solubility of Si and Ge in liquid Au for vapor-liquid-solid (VLS) grown nanowires, the transition region width between an axial Si-Ge heterojunction is typically on the order of the nanowire diameter. When the solute solubility in the catalyst is lowered, the heterojunction width can be made sharper. Here we show for the first time the systematic increase in interface sharpness between axial Ge-Si heterojunction nanowires grown by the VLS growth method using a Au-Ga alloy catalyst. Through in situ tailoring of the catalyst composition using trimethylgallium, the Ge-Si heterojunction width is systematically controlled by tuning the semiconductor solubility within a metal Au-Ga alloy catalyst. The present approach of alloying to control solute solubilities in the liquid catalyst may be extended to increasing the sharpness of axial dopant profiles, for example, in Si-Ge pn-heterojunction nanowires which is important for such applications as nanowire tunnel field effect transistors or in Si pn-junction nanowires. 相似文献
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C.Y. KuoC. Gau 《Thin solid films》2011,519(11):3603-3607
Silicon nanowires (SiNWs) were grown at low temperatures close to metal silicon eutectic point on a silicon substrate using gold catalyst coupled with assistance of the aluminum anodic oxide template. Either a vapor-solid-solid (VSS) growth process below metal silicon eutectic temperature or a vapor-liquid-solid (VLS) process at slightly higher temperatures was observed. The transmission electron microscopy coupled with both the X-ray energy dispersive spectroscopy and the selected area electron diffraction was adopted to characterize the SiNWs. Although the mechanism triggering the VSS process is still not clear, both the geometric and morphological characteristics of the SiNWs grown by the VSS process are discussed and compared with the SiNWs grown by the VLS process. The VSS SiNWs have a much slower growth rate (less than 100 nm/h), a smaller and more uniform diameter (in the range of 15.22 nm) due to a much slower rate of silicon diffusion and much smaller amount of silicon (6.8 wt.%) dissolved in the solid nanocatalyst. 相似文献