Pyramid-Shaped Single-Crystalline Nanostructure of Molybdenum with Excellent Mechanical, Electrical, and Optical Properties
Pyramid-Shaped Single-Crystalline Nanostructure of Molybdenum with Excellent Mechanical, Electrical, and Optical Properties
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具有优异机械、电学和光学性能的金字塔形单晶钼纳米结构
DOI：
10.1021/acsami.0c02351
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发表时间：
2020
影响因子：
9.5
通讯作者：
Deng Shaozhi
中科院分区：
文献类型：
--
作者：
Shen Yan;Han Yuchen;Zhan Runze;Chen Xuexian;Wen Shiya;Huang Wuchao;Sun Fengsheng;Wei Yaoming;Chen Huanjun;Wu Jin;Chen Jun;Xu Ningsheng;Deng Shaozhi
特定的几何形貌和改善的结晶性能对于材料在微纳米尺度上的发展具有重要意义。然而，对于高熔点钼（Mo），难以获得同时表现出单晶性质和预想形态的高质量结构。本文采用热蒸发技术制备了一种“U”形单晶钼纳米结构，并进行了一系列的实验控制。基于详细的表征，生长机制被证明是遵循一个顺序的过程，包括MoO 2分解和Mo沉积，单晶岛的形成，分层成核，竞争生长。此外，产物经测量显示出优异的物理性质。所制备的纳米结构表现出很强的纳米压痕硬度，弹性模量和拉伸强度在机械测量，这是远远高于那些钼块。在电子特性的测量中，各个结构显示出非常好的电输运性质，电导为10.16 S。所制备的薄膜面积为0.02 cm-2，具有大电流电子发射性能，最大电流为33.6 mA，电流密度为1.68 A cm-2。光学性能测试表明，该结构具有明显的电磁场局域化和增强效应，使其作为基底材料具有良好的表面增强拉曼散射（Sers）活性。进一步讨论了相应的结构-响应关系。所报道的物理性质得益于Mo纳米结构的基本特征，包括微纳米尺度、每个晶粒中的单晶性质以及顶部形貌。这一发现可能为微纳电子和光子的研究和应用提供潜在的材料。
Specific geometric morphology and improved crystalline properties are of great significance for the development of materials in micro–nano scale. However, for high-melting molybdenum (Mo), it is difficult to get high-quality structures exhibiting a single-crystalline nature and preconceived morphology simultaneously. In this paper, a pyramid-shaped single-crystalline Mo nanostructure was prepared through a thermal evaporation technique, as well as a series of experimental controls. Based on detailed characterizations, the growth mechanism was demonstrated to follow a sequential process that includes MoO2decomposition and Mo deposition, single-crystalline islands formation, layered nucleation, and competitive growth. Furthermore, the product was measured to show excellent physical properties. The prepared nanostructures exhibited strong nano–indentation hardness, elastic modulus, and tensile strength in mechanical measurements, which are much higher than those of the Mo bulks. In the measurement of electronic characteristics, the individual structures indicated very good electrical transport properties, with a conductance of ∼0.16 S. The prepared film with an area of 0.02 cm2showed large-current electron emission properties with a maximum current of 33.6 mA and a current density of 1.68 A cm–2. Optical properties of the structures were measured to show obvious electromagnetic field localization and enhancement, which enabled it to have good surface enhanced Raman scattering (SERS) activity as a substrate material. The corresponding structure–response relationships were further discussed. The reported physical properties profit from the basic features of the Mo nanostructures, including the micro–nano scale, the single-crystalline nature in each grain, as well as the pyramid-shaped top morphology. The findings may provide a potential material for the research and application of micro–nano electrons and photons.