FUNCTIONAL NANOWIRES, NANOWIRE HETEROSTRUCTURES AND THREE-DIMENSIONAL NANOWIRE NETWORKS

半导体工业的ITRS路线图已经确定了半导体纳米线作为一种可能的途径，通过这种途径，摩尔定律的尺寸缩放可以扩展到更小的维度。纳米线可以同时用作逻辑元件和存储元件，在未来的半导体技术中，器件尺寸小于10纳米。因此，纳米线研究领域目前特别活跃，有望在中长期内实现实际应用。在本研究中，我将讨论两个必须解决的关键问题，如果纳米线的应用要在电子领域产生影响：(I)纳米线如何相互连接以形成有用的电路？（ii）哪些独特的功能特性可以被设计成纳米线并用于应用？解决第一个问题的实验将集中在使用有机支架沉积（OSD）来生长三维金属纳米线网络。特别是，我们将研究使用OSD的磁性纳米线的生长，最终目标是为高密度计算机存储应用创建三维磁性存储介质。解决第二个问题的实验将集中在半导体和超导纳米线上。对于半导体纳米线，我们将使用已建立的纳米粒子种子分子束外延（NS-MBE）技术，并将其扩展到各种III-V和II-VI材料。使用NS-MBE，我们将能够通过在生长过程中改变前驱体材料来调节纳米线沿着其长度的特性。（这项技术已经被证明可以在InP/InAs系统中产生原子锋利的材料界面。）因此，NS-MBE为我们提供了一个工具箱，用于研究降维在许多功能材料和异质结构中的作用，包括（例如）稀磁半导体和异质结构光子器件。超导纳米线将使用聚焦离子束和OSD技术生长。这些纳米线显示了一系列新的物理现象，将被研究用于红外量子密钥分配系统的单光子探测器和量子电流标准。

The ITRS roadmap for the semiconductor industry has identified semiconducting nanowires as a possible route by whichthe size-scaling of Moore's Law can be extended to yet smaller dimensions. Nanowires could be used both as the logicelements and the memory elements in a future semiconductor technology with device dimensions below 10 nm. The fieldof nanowire research is therefore particularly active at present and can be expected to deliver real applications in themedium to long term.In this fellowship I will address two key issues which must be resolved if nanowire applications are to make an impact inthe electronics sector:(i) How can nanowires be interconnected to form useful circuits?(ii) What unique functional properties can be engineered into nanowires that can be exploited in applications?Experiments to address the first of these issues will focus on using organic scaffold deposition (OSD) for growth of three-dimensional metallic nanowire networks. In particular we will study the growth of magnetic nanowires using OSD with the ultimate aim of creating a three-dimensional magnetic storage medium for high-density computer memory applications.Experiments to address the second issue will concentrate on semiconducting and superconducting nanowires. For semiconducting nanowires we will use the established nanoparticle-seeded molecular beam epitaxy (NS-MBE) technique and extend it to a variety of III-V and II-VI materials. Using NS-MBE we will be able to modulate the properties of the nanowire along its length simply by changing the precursor material during growth. (This technique has already been demonstrated to result in atomically sharp materials interfaces in the InP/InAs system.) NS-MBE therefore gives us a toolkit for studying the role of reduced dimensionality on a number of functional materials and heterostructures, including (for example) dilute magnetic semiconductors and heterostructure photonic devices.Superconducting nanowires will be grown using focussed-ion-beam and OSD techniques. These nanowires, which display a range of new physical phenomena, will be studied for applications as single photon detectors for use in infra-red quantum key distribution systems and as quantum current standards.