Collaborative Research: Studies of Explosive Crystallization

提案编号：CTS-0431431 CTS-0431409主要研究员：Benard J.Matkowsky和Alexander A.GolovinCostas Grigoropoulos从属：西北大学加州大学伯克利分校提案标题：合作研究：爆炸性结晶研究摘要无定形材料的爆炸性结晶是一种令人着迷的现象，二十多年来一直吸引着工程师、物理学家、材料科学家和其他人的注意。它表现为固体材料从亚稳态非晶态到稳定晶态的热激活、高放热相变，这种相变以自蔓延结晶前沿的形式发生。前波传播可以由机械产生的局部热上升或由激光束触发。激光触发非晶半导体薄膜爆炸结晶是一种应用广泛的现代绝缘体上硅结构技术，在太阳能电池或红外探测器、低成本、低功耗平板显示器等光伏器件中有着广泛的应用。本项目的目标是启动和发展西北大学理论小组和伯克利大学实验小组之间富有成效的合作，对爆炸结晶的几个以前没有研究过的重要方面进行系统的理论和实验研究。这项合作将集中在爆炸结晶前沿和由此产生的微结构所表现出的不稳定性的非线性动力学的数学建模和实验研究上。具体地说，我们建议研究几种不同锋面传播模式下爆炸结晶前沿的稳定性和非线性动力学，以及合金中的爆炸结晶以及掺杂对结晶动力学的影响。从根本上讲，这项研究的意义在于阐明了爆炸结晶前沿在几种模式下的不稳定性和非线性动力学等重要影响，为远离热力学平衡的体系中复杂的非线性行为提供了范例。从工艺角度来看，研究结果将加深我们对非晶薄膜爆炸结晶现代工艺过程的理解。已建立的合作将使我们能够在未来的联合研究中进一步深入研究爆炸结晶材料中的微结构，这是控制和优化工艺的必要前提。拟议研究的更广泛影响在于它的跨学科性质，以及它对科学家和工程师的重要性。这项研究由数学和物理科学局的数学科学部和工程部的化学和运输系统司共同资助。资金来自NSF 04-538宣布的数学科学：与科学和工程计划接口的创新。

Proposal Number: CTS-0431431CTS-0431409Principal Investigator: Benard J. Matkowsky and Alexander A. GolovinCostas GrigoropoulosAffiliation: Northwestern UniversityUniversity of California-BerkeleyProposal Title: Collaborative Research: Studies of explosive crystallizationAbstractExplosive crystallization of amorphous materials is a fascinating phenomenon that has attracted much attention from engineers, physicists, materials scientists and others for over two decades. It manifests itself as a thermally activated, highly exothermic phase transition of a solid material from a metastable amorphous state to a stable crystalline state, that occurs in the form of a self-propagating crystallization front. The front propagation can be triggered by a local heat rise produced mechanically, or by a laser beam. The laser-beam-triggered explosive crystallization of amorphous semiconductor films is a widely used modern technology for producing silicon-on-insulator structures that have many applications in various photovoltaic devices like solar cells or infrared detectors, low-cost, low-power consuming at panel displays, etc. The objective of the proposed project is to initiate and develop a fruitful collaboration between the theoretical group at Northwestern and the experimental group at Berkeley, to carry out systematic theoretical and experimental investigations of several important aspects of explosive crystallization that have not been previously studied. The collaboration will focus on mathematical modeling and experimental studies of nonlineardynamics of instabilities exhibited by explosive crystallization fronts and the resulting microstructures. Specifically, we propose to investigate the stability and nonlinear dynamics of explosive crystallization fronts in several different modes of frontal propagation, as well as explosive crystallization in alloys and the effect of dopants on the crystallization dynamics. From the fundamental point of view, the significance of the proposed research is in elucidating such important effects as the instabilities and nonlinear dynamics of explosive crystallization fronts in several modes that provide examples of complex nonlinear behavior in systems far from thermodynamic equilibrium.From the technological point of view, the results will enhance our understanding of the modern technological process of explosive crystallization in thin amorphous films. The established collaboration will allow us to move further in our future joint research to more detailed investigations of microstructure in explosively crystallizing materials which is a necessary prerequisite to control and optimization of the process. The broader impact of the proposed research lies in its interdisciplinary nature, its importance for bothscientists and engineers. It will also create a sound basis for training graduate students in future stages of the collaborative research that will provide them with the unique opportunity to participate in important research at the cutting edge of engineering, applied physics and applied mathematics, combining both theoretical and experimental components.This research has been funded jointly by the Division of Mathematical Sciences in the Mathematics and Physical Sciences Directorate and the Division of Chemical and Transport Systems in the Engineering Directorate. Funding is from the Mathematical Sciences: Innovations at the Interface with the Sciences and Engineering Program, Announcement NSF 04-538.