Novel metallic and semiconductor nanorod/nanowire architectures

该项目的重点是详细研究新型半导体和金属纳米棒结构，以便更好地了解生长过程和与大块材料的性能差异。外延生长的单晶半导体纳米棒和周期性纳米棒阵列可以通过使用纳米结构衬底来实现。自组装胶体颗粒（主要是聚苯乙烯亚微米尺寸的单分散球体）单层的形成是公认的，并广泛应用于各个研究领域。纳米球光刻（NSL）将用于创建周期性和准周期性自组装球形物体，如直径在200至2000 nm范围内的聚苯乙烯或二氧化硅颗粒。二维和三维（2-D，3-D）有序颗粒将被用作掩模，用于随后沉积不同量的不同金属。在蒸发工艺之后，将执行掩模的剥离。金属2-D和3-D变化的颗粒阵列允许控制纳米管之间的距离以及它们的立方、六方或更复杂的排序。在纳米结构衬底上生长的最终纳米管将通过等离子体增强化学气相沉积来完成。通过掩模沉积的催化剂的量可以决定生长的纳米管的厚度，进而可以直接影响它们的光学和电子性质。纳米棒和纳米线的湿化学合成已经通过表面活性剂引导的聚集/聚结或在2- 5 nm种子颗粒上的外延生长完成。在大多数情况下，所涉及的生长机制仍然是未知的;这些生长机制的阐明将是本项目的主要重点。正如人们可以预期的那样，不同的材料（如金属和半导体）的生长机制不同，我们将研究金属和半导体纳米棒和纳米线。该项目的另一个重点将是对最终材料性能的研究。研究将采用紫外/维斯光谱、光学显微镜、原子力显微镜、透射电子显微镜和电子能量损失光谱。

The focus of this project is a detailed study of novel semiconductor and metallic nanorod architectures in order to gain a better understanding of the growing process and difference in properties to those of the bulk materials. Epitaxially grown single-crystalline semiconductor nanorods and periodic nanorod arrays can be realized by use of nanostructured substrates. The formation of monolayers of self-assembled colloidal particles (mainly polystyrene submicron-sized, monodisperse spheres) is well-established and widely used in various fields of research. Nanosphere lithography (NSL), will be used for the creation of periodic and quasiperiodic self assembly spherical objects like polystyrene or silica particles with a diameter in the range of 200 to 2000 nm. The two and three-dimensional (2-D, 3-D) ordered particles will be used as a mask for the following deposition of various amounts of different metals. After the evaporation process the liftoff of the mask will be performed. The metallic 2-D and 3-D varying particle arrays permit the control of the distance between the nanotubes as well as their cubic, hexagonal or more complicated ordering. The final nanotubes grown on nanostructured substrates will be done by plasma enhanced chemical vapor deposition. The amount of catalyst deposited through the mask can determine the thickness of growing nanotubes with can in turn directly influence their optical and electronic properties. Wet chemical synthesis of nanorods and nanowires has been done by surfactant directed aggregation/coalescence of - or epitaxial growth on 2-5nm seed particles. The growing mechanisms involved are in most cases still unknown; the elucidation of these growing mechanisms will be a major focus of this project. As one can expect that growing mechanisms differ for different materials such as metals and semiconductors, we will investigate metallic- and bimetallic-, as well as semiconducting nanorods and nanowires. A further focus of this project will be the investigation of the properties of the final materials. Investigations will be done applying UV/VIS- spectroscopy, optical microscopy, atomic force microscopy, transmission electron microscopy, and electron energy loss spectroscopy.