Growth, Fabrication, and Characterization of Novel Semiconductor Nanostructures

研究半导体材料的性质是我们技术文明的基础之一。半导体材料是实现计算机、无线技术、光纤通信和太阳能发电等电子设备的基础。这些设备都是基于对基础材料科学及其创新潜力的详细了解。 纳米线是直径在纳米范围(10-9米)的半导体材料的非常细的线，由于其直径非常小，具有不寻常的性质；例如，由于量子效应，电子在非常细的线中的性质和行为是不同的。纳米线的高比表面积体积比既是一个潜在的优势(例如，对于气体传感器)，也是一个缺点(例如，对于发光设备和太阳能电池)。近年来，在形成纳米线的方法方面取得了重大进展，用于许多应用，包括超高速晶体管、太阳能电池、气体传感器、高效光发射器和大比表面积纳米材料。 这项研究计划的目的是对半导体纳米结构，特别是纳米线的物理学有一个清楚的了解，目的是将这些新结构用于设备中。实用的半导体器件依赖于材料缺陷：一方面，必须引入杂质以控制导电；另一方面，某些缺陷，如出现在材料表面的缺陷，可能会产生负面影响。这在纳米线中可能是个问题，因为在纳米线中，电子离表面很近。 这项建议侧重于理解半导体纳米线科学的两个关键挑战。首先，我们建议开发新的和可控的方法来形成特定的纳米线结构，这些结构可以用于原型设备应用，如太阳能电池和发光二极管。这包括开发方法在可用于形成器件原型的结构中生长特定材料(砷化镓、氮化镓、铟砷、氧化锌及相关材料)。其次，我们将利用先进的电子显微镜方法和低温光学光谱学，开发新的方法来量化表面和体缺陷对半导体纳米线中电子和空穴行为的作用。我们的双管齐下的方法将使我们能够开发和测试简单的原型纳米线设备结构，这些结构将形成未来工业应用的基础。 拟议的研究将利用我们的成果和合作，并继续在这一领域设定新的方向。这一研究计划将培养未来的领导者，他们拥有半导体生长和表征方面的专业知识，以及电子显微镜技术，他们将为研究和工业应用做出贡献。

Research into the properties of semiconductor materials is one of the foundations of our technological civilization. Semiconductor materials provide the backbone of electronic devices used to enable computers, wireless technologies, fibre optic communications, and solar power generation, among others. These devices have all been based on a detailed understanding of fundamental materials science and its potential for innovation. Nanowires are very thin wires of semiconductor materials with diameters in the nanometer range (10-9m) that have unusual properties by virtue of their very small diameters; for example, the properties and behaviour of electrons are different in very thin wires due to quantum effects. The high surface area-to-volume ratio of nanowires is both a potential advantage (e.g., for gas sensors) and a drawback (e.g., for light emitting devices and solar cells). In recent years, there has been significant progress in methods to form nanowires for use in a number of applications, including extremely high speed transistors, solar cells, gas sensors, high efficiency light emitters, and large surface area nanomaterials. The aim of this research proposal is to gain a clear understanding of the physics of semiconductor nanostructures, particularly nanowires, with the goal to use these novel structures in devices. Practical semiconductor devices rely on materials defects: on one hand, impurities must be introduced in order to control electrical conduction; on the other hand, certain defects, such as those that arise at the surfaces of materials, can have a negative effect. This can be problematic in nanowires, where the electrons are in close proximity to the surface. This proposal focuses on two key challenges in understanding the science of semiconductor nanowires. First, we propose to develop novel and controlled methods for the formation of specific nanowire structures that can be used in prototype device applications, such as solar cells and light emitting diodes. This includes developing methods to grow specific materials (GaAs, GaN, InAs, ZnO, and related materials) in structures that can be used to form device prototypes. Second, we will develop new ways of quantifying the role of surface and bulk defects on the behaviour of electrons and holes in semiconductor nanowires using advanced electron microscopy methods and low temperature optical spectroscopy. Our two-pronged approach will enable us to develop and test simple prototype nanowire device structures that will form the basis of future industrial applications. The proposed research will capitalize on our achievements and collaborations, and continue to set new directions in this field. This research program will train future leaders, equipped with expertise in semiconductor growth and characterization, and electron microscopy techniques, who will contribute to both research and industrial applications.