铋纳米线阵列通过真空热蒸发无核增长
Summary
A protocol for seedless and high yield growth of bismuth nanowire arrays through vacuum thermal evaporation technique is presented.
Abstract
这里一个无籽和无模板技术被证明可伸缩在高真空中在RT生长铋纳米线，通过热蒸发。为金属薄膜，热蒸发沉积的制造铋成垂直单晶纳米线以上的钒在室温保持一个平坦的薄膜，这是新鲜的磁控溅射或热蒸发沉积的阵列通常保留。通过控制生长衬底的温度的纳米线的长度和宽度可以调节在宽范围内。负责这种新颖的技术是一种以前未知的纳米线生长机理，在钒薄膜的孔隙率温和根。渗入毛孔钒，铋域（约1纳米）进行过度的表面能，抑制它们的熔点，不断驱逐出来的钒基体形成纳米线。这一发现证明了可扩展的气相合成器的可行性高纯度纳米材料ESIS不使用任何催化剂。
Introduction
纳米线限制电荷载体和其他的准粒子，诸如光子和等离子体的传输在一个方面。因此，纳米线通常表现新颖的电，磁，光，化学性能，这对于微/纳米电子学，光子学，生物医学，环境和能源相关技术的应用赋予他们几乎无限的潜力。1,2在过去的二十年中，无数顶向下和自底向上方法已经发展到合成各种高品质的金属或半导体纳米线的在实验室规模3-6尽管这些进展，每一种方法依赖于对于其成功的最终产品的某些独特性质。例如，流行的气-液-固（VLS）的方法是更适合用于具有较高的熔点，并与相应的催化“种子”形成共晶合金。7作为结果，半导体材料，纳米线的合成特别令人感兴趣的材料可能不被包括在现有的技术。
作为一种半金属小间接带重叠（-38兆电子伏在0 K）和不寻常的光电荷载体，铋就是这样一个例子。相比，其体积的材料表现在降低的尺寸完全不同，因为量子约束可以把铋纳米线或薄膜成窄带隙半导体8-12在此期间，铋形成表面上的准二维金属比其体积显著多种金属。13,14-结果表明铋的表面达到2×10 4厘米2 V -1 秒 -1的电子迁移率和强烈有助于其热电功率在纳米线的形式。15作为这样，有钻研铋纳米线为电子，特别热电应用显著利益12-16然而，由于铋的非常低的熔点（544 K）和准备用于氧化，但仍然为合成高品质和使用传统的汽相或溶液相技术单晶铋纳米线是一个挑战。
此前，已经报道由几组，在铋薄膜，这是由于应力的内置于膜中的释放的真空沉积单晶铋纳米线生长在低收率17-20最近，我们发现了一种新技术，它是基于在高真空下铋的热蒸发，并导致高收率可伸缩形成单晶铋纳米线。21相较于先前报道的方法，该技术的最独特的特征是，在生长衬底是新鲜涂覆有一层薄薄的铋沉积之前纳米多孔钒。在后者的热蒸发，铋蒸汽渗透到车的纳米多孔结构Adium的电影和凝结那里作为纳米畴。因为钒未被冷凝的铋润湿，渗透的域随后从钒矩阵逐出释放其表面能。它是铋纳米畴形成垂直铋纳米线的连续驱逐。由于铋域只有1-2纳米的直径，他们是受显著熔点抑制，这使得他们几乎熔化在室温。其结果是，纳米线的生长与在室温保持的基板进行。另一方面，作为铋畴的迁移被热激活时，纳米线的长度和宽度，可以通过简单地控制生长衬底的温度调谐在宽范围内。该详细视频协议的目的是帮助新从业人员在实地避免与薄膜中的高真空，无氧的环境中的物理汽相沉积相关联的各种常见的问题。
Protocol
Representative Results
Discussion
铋纳米线的生长是要在物理气相沉积系统具有至少两个沉积源，一个用于铋，另一个用于钒进行的。所以建议的来源之一是一个磁控管溅射源，钒的沉积。高真空是通过干式涡旋泵的支持一个分子泵实现。的气相沉积系统， 在原地膜厚监控配备校准的石英晶体微天平（QCM）为。的气相沉积系统具有电馈送对于生长衬底闭环温度控制。热电温度控制器提供加热/冷却到衬底上，通过被热粘合?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Research is carried out at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-SC0012704.
Materials
| Bismuth | Sigma-Aldrich | 556130 | Granular, 99.999% |
| Vanadium Slug | Alfa Aesar | 42829 | 3.175mm (0.125in) dia x 6.35mm (0.25in) length, 99.8% |
| Vanadium Sputtering Target | Kurt J. Lesker | EJTVXXX253A2 | 3.00" Dia. x 0.125" Thick, 99.5% |
| Acetone | Sigma-Aldrich | 179124 | >99.5% |
| Ethanol | Alfa Aesar | 33361 | Anhydrous |
| Silicon Wafer | University Wafers | 300 microns in thickness, (100) orientation | |
| Silver Filled Epoxy | Circuit Works | CW2400 | Two part conductive epoxy resin |
| Tungsten Boat, Alumina Coated | R. D. Mathis | S9B-AO-W | For bismuth thermal evaporation |
| Tungsten Boat | R. D. Mathis | S4-.015W | For vanadium thermal evaporation |
| RIE Plasma | Nordson March | CS-1701 | |
| PVD 75 Vapor Deposition Platform | Kurt J. Lesker | PEDP75FTCLT001 | Equipped with three thermal evaporation source and one DC magnetron sputtering source |
| Thermoelectric Temperature Controller | LairdTech | MTTC-1410 | |
| PT1000 RGD | LairdTech | 340912-01 | Temperature sensor for MTTC-1410 |
| Thermoelectric Module | LairdTech | 56910-502 | |
| Ultrasonicator | Crest Ultrasonics | Tru-Sweep 175 |
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