Fundamentals of thin film growth from the vapor phase and through solid-state reactions

薄膜几乎存在于所有日常产品中，从眼镜上的减反射涂层到切割工具上的硬涂层，再到电脑显示器。特别是，它们是微电子和光电子设备的核心：计算机芯片、发光二极管、半导体激光器、太阳能电池、平板显示器，仅举几例。为了应对不断增长的性能改进需求，单层膜已逐渐被复杂的多层膜和异质结构所取代。对涂层和器件设计更具灵活性的需求已经刺激并继续推动具有可裁剪特性的人工纳米结构材料的发展。“薄膜”产业正在快速扩张。它代表了一个100G美元的市场，2008年终端市场规模为2300G美元。预计到2030年，这两个数字将分别增加到400G美元和7000G美元。虽然信息技术一直被认为是一个主要的应用领域，但最引人注目的进展预计将在能源、交通、环境和健康领域。我们的最终目标是详细了解薄膜生长过程中表面和界面上发生的原子过程，以便制造出具有预定性能的材料。我们的第一个目标是研究从汽相中生长石墨烯的局部细节，以便优化其制备。石墨烯-碳原子的单层平面-是一种具有独特性质的二维材料。石墨烯是透明的，具有良好的导电和导热性能，例如，它被设想为太阳能电池和显示器的可调透明电极。我们试图对各种气体物种和生长参数对石墨烯的形成和蚀刻的不同影响进行详细的局部理解。我们希望确定氧化性杂质攻击新形成的石墨烯岛的位置，并了解所涉及的化学物种的催化作用。我们的第二个目标是了解织构遗传在晶体生长中的作用，并通过设计实现对异质材料和亚稳态相形成的精确控制。纹理--给定材料中颗粒取向的分布--对薄膜的性能有深远的影响。例如，它影响涂层的硬度、薄导体的电迁移阻力以及界面的稳定性。更具体地说，我们将研究用于与最先进集成电路中的晶体管形成接触的固态反应。我们将专注于通过使用掺杂剂和合金化元素来调节所需反应薄膜的性质来操纵该反应。在一系列补充实验中，我们将利用织构遗传来形成用于自旋电子学的异质磁性/半导体薄膜。我们的研究计划力求在纳米材料领域产生最高的科学和技术影响。我们预计，我们的研究结果将广泛应用于薄膜合成领域的大量应用领域，包括(光学)电子器件制造和材料表面改性。我们相信，这些结果将导致在这些领域以及相关领域进行意义深远的新研究。高素质人才的培训是我们研究的一个组成部分，因为研究生和博士后研究员将获得关于薄膜生长、表面物理以及材料物理和表征的深入知识，为他们在加拿大大学、国家实验室和行业的研发生涯做好完美的准备。

Thin films are found in nearly all everyday products, from antireflective coatings on glasses to hard coatings on cutting tools to computer displays. In particular, they are the core of micro- and optoelectronic devices: computer chips, light emitting diodes, semiconductor lasers, solar cells, flat panel displays, just to name a few. In answer to continuously increasing demands for improved performance, single layers have gradually been replaced by complex multilayers and heterostructures. The demand for more flexibility in coating and device design has stimulated and continues to drive the development of artificially nanostructured materials with tailorable properties. The “thin film” industry is expanding at a rapid pace. It represented a market of 100 G$ with an end-market size of 2300 G$ in 2008. These numbers are forecast to increase to 400 G$ and 7000 G$, respectively, by 2030. While information technology has always been recognized as a major application sector, the most spectacular gains are predicted to be in energy, transportation, environment, and health.Our ultimate goal is to develop a detailed understanding of atomic processes occurring on surfaces and at interfaces during the growth of thin films in order to produce materials with predetermined properties. Our first objective is to investigate the local details of the growth of graphene from the vapor phase in order to optimize its fabrication. Graphene – a monolayer plane of carbon atoms – is a bidimensional material with unique properties. Being transparent and exhibiting good electrical and thermal conduction properties, graphene is envisioned, for example, as a tunable and transparent electrode for solar cells and displays. We seek to develop a detailed local understanding of the distinct effects of the various gaseous species and growth parameters on the formation and etching of graphene. We want to identify the sites where oxidizing impurities attack newly formed graphene islands and to understand the catalytic effects of the chemical species involved.Our second objective is to understand the role of texture inheritance in crystal growth, and to progress towards the precise control of the formation of heterogeneous materials and metastable phases by design. Texture – the distribution of grain orientations in a given material – has a profound effect on film properties. It influences, for example, the hardness of coatings, the resistance to electromigration in thin conductors, and the stability of interfaces. More specifically, we will investigate the solid state reaction used to form contacts with transistors in the most advanced integrated circuits. We will focus on manipulating this reaction through the use of dopants and alloying elements for tuning the properties of the desired reacted films. In a complementary set of experiments, we will exploit texture inheritance for forming heterogeneous magnetic/semiconductor films for spintronics.Our research program strives for the highest scientific and technological impact in the area of nanoscale materials. We anticipate that the results of our research will be broadly applicable in the field of thin film synthesis in a large number of application areas including, for example, (opto)electronic device fabrication and surface modification of materials. We are confident that the results will lead to far-reaching new research in these, as well as related, areas. Training of highly qualified personnel is an integral part of our research as graduate students and postdoctoral fellows will acquire an in-depth knowledge of film growth, surface physics, as well as materials physics and characterization that prepares them perfectly for R&D careers in Canadian universities, national laboratories, and industries.