Dynamical Processes of Epitaxial Growth

9618656科恩这个项目解决了外延生长的动态过程。对于GaAs，我们将用RHEED和STM研究表面形态的演变、岛的形成、交叉流动到阶跃流动，以及吸附原子在生长动力学和形态中的作用。一个重要的目标是利用所获得的知识来发展对薄膜生长的原子水平的理解和控制。能量过滤RHEED将被用来改善与动力学计算的对比，并消除漫反射强度测量中的不确定性。在衍射相关函数分析中，将考虑阶跃边缘散射因子。该项目还将研究在块状GaN晶片(晶须)上生长GaN；该方法用于消除蓝宝石上GaN生长通常存在的非晶态缓冲层的作用。其目的是获得与微观生长过程有直接关系的外延过程的明确数据。%该项目致力于具有高度技术相关性的材料科学主题领域的前沿研究问题。这项研究将在基础水平上为电子/光子器件和集成电路的重要方面贡献基本的材料科学知识。此外，从研究中获得的基本知识和理解有望通过为设计和生产改进的材料和材料组合提供基本的理解和基础，从而在总体上为提高先进器件和电路的性能做出贡献。该计划的一个重要特点是通过在一个具有根本意义和技术意义的领域对学生进行培训，将研究和教育结合起来。***

9618656 Cohen This project addresses dynamical processes of epitaxial growth. For GaAs, the evolution of surface morphology, island formation, crossover to step flow, and the role of adatoms in growth kinetics and morphology will be studied using RHEED and STM. An important goal is to use the knowledge obtained to develop atomic level understanding and control over film growth. Energy-filtered RHEED will be used to improve the comparison with dynamical calculations and to eliminate uncertainties in the measurement of diffuse intensities. Step edge scattering factors will be considered in the correlation function analysis of diffraction. The project will also study GaN growth on bulk GaN platelets(whiskers); this approach is used to remove the role of the amorphous buffer layer normally present with GaN growth on sapphire. The aim is to obtain definitive data on epitaxial processes having direct relationships to microscopic processes of growth. %%% The project addresses forefront research issues in a topical area of materials science having high technological relevance. The research will contribute basic materials science knowledge at a fundamental level to important aspects of electronic/photonic devices and integrated circuitry. Additionally, the fundamental knowledge and understanding gained from the research is expected to contribute in a general way to improving the performance of advanced devices and circuits by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***