Coherent X-ray Studies of Surface Growth and Patterning Processes

非技术描述：控制材料表面的生长和纳米级图案对能源、通信和信息技术的许多应用至关重要。然而，开发更有用的材料的一个主要障碍是很难测量在这些过程中表面结构的演变。这项研究通过使用非常强的X射线来测量生长和图案化过程中表面上的纳米级动态，从而应对了这一挑战。这些实验是通过使用最新的x射线源实现的，这些x射线源一直在迅速发展，亮度越来越高。实验测量与理论和计算机模拟的预测进行了比较，从而增加了理解和预测能力。这些知识可以帮助科学家和工程师更好地控制材料的表面过程，增强他们的技术能力。此外，该项目还培训研究生、本科生和高中生，使他们了解材料研究这一非常重要且发展迅速的部分，从而引领材料创新的未来职业生涯。技术描述：这项研究正在开发x射线光子相关光谱，将其作为一种强大的新方法来研究生长和离子束构图过程中表面的纳米级动力学。考虑到S这项技术在解决这些具有挑战性的问题的早期应用阶段，考察它的能力范围是很重要的。因此，该项目正在调查一组精心选择的系统和行为。首先，它被用来仔细研究非晶膜生长过程中动力学粗化的基本过程，这是一个长期感兴趣和有争议的问题。其次，在有机半导体薄膜的气相沉积和III-V氮化物外延薄膜的等离子体辅助原子层外延生长的背景下，正在研究该技术在研究外延生长过程中的适用性。最后，正在研究半导体离子束纳米刻蚀的动力学，这是一个在实验和理论之间产生异常密切互动的问题。在所有情况下，都在进行连续统和原子模型的模拟，以将观测与潜在的机制联系起来。参与的研究生、本科生和高中生都有很好的机会在基础研究和应用之间架起桥梁的领域工作。参与课程的学生学习广泛的表征和计算工具，这些工具可以很好地转化为未来在工业或学术界的职业生涯。

Nontechnical description: Controlling the growth and nanometer-scale patterning of materials surfaces is critical to many applications in energy, communication and information technologies. However, a major impediment to developing more useful materials is the difficulty of measuring the evolution of surface structure during such processes. This research meets that challenge by using very intense x-rays to measure the nanometer-scale dynamics on surfaces during growth and patterning. These experiments are made possible by the use of the latest x-ray sources, which have been rapidly developing increasing brightness. The experimental measurements are compared with predictions of theory and computer simulations, leading to increased understanding and predictive power. Such knowledge can help scientists and engineers better control surface processes on materials, enhancing their technological capabilities. In addition, the project trains graduate, undergraduate and high school students in this very important and rapidly developing part of materials research, leading to future careers in materials innovation.Technical description: This research is developing x-ray photon correlation spectroscopy as a powerful new approach to investigating the nanoscale dynamics of surfaces during growth and ion beam patterning. Given the technique?s early stage of application to such challenging problems, it is important to examine the range of its capabilities. This project is therefore investigating a carefully chosen set of systems and behaviors. First, it is being used to carefully probe the fundamental processes in kinetic roughening during amorphous film growth, an issue of long-standing interest and controversy. Second, the applicability of the technique to investigating epitaxial growth processes is being examined within the context of vapor deposition of organic semiconductor films and plasma-assisted atomic layer epitaxial growth of III-V nitride epitaxial films. Finally, the dynamics of semiconductor ion beam nanopatterning, an issue generating unusually close interaction between experiment and theory, is being studied. In all cases, simulations of continuum and atomistic models are being performed to relate observations to underlying mechanisms. Graduate, undergraduate and high school students involved have an outstanding opportunity to work in an area that bridges basic research and application. Participating students learn a wide range of characterization and computational tools that can translate well to future careers in industry or academia.