Exploring Growth Mechanisms of Nonequilibrium Nanostructured Materials

Wayne State University, Detroit MI

Investigators

Abstract

NONTECHNICAL SUMMARY This project supports theoretical and computational research on the study of novel materials growth mechanisms and the integration with education and outreach activities. An important phenomenon during the materials growth or fabrication process is the formation and evolution of structures at the nanoscale, which plays a pivotal role in controlling material properties that are of fundamental and technological importance. This research addresses a fundamental challenge of understanding and predicting the growth and self-assembly of nanostructured materials, particularly how to effectively tackle the complexity of the systems which are far from the tranquil state of equilibrium and require a description that can span a wide range of length scales and include interconnected processes across length scales. The PI will develop predictive modeling methods and conduct theoretical analyses and computer simulations to investigate the growth and dynamics of novel nanostructures that emerge from these processes, and predict new types of modulated structures in thin films under various material growth or processing conditions. This project supports the training and education of graduate students, and involves the PI's broader education efforts for the research community through lecture development for summer schools and workshops. This project incorporates the PI's outreach activities for STEM education in an all-girls minority public school in Detroit. The activities include the instruction and support of high-school student science projects and the training of Wayne State education undergraduates, to enhance the K-12 STEM education for young women who are underrepresented minority students and the professional development of both pre-service and in-service science teachers. TECHNICAL SUMMARY This project supports theoretical and computational research integrated with education to provide a systematic study on the growth and dynamics of nonequilibrium nanostructured materials. The research addresses a fundamental challenge of understanding and predicting the growth mechanisms underlying the nanostructure assembly in functional material systems, particularly for systems that are out of equilibrium and governed by effects of coupling among different spatial scales that control material microstructures and dynamics. This research focuses on the exploration of novel nanostructures that are both morphologically and compositionally modulated, through three parts of investigation: (i) the development of modeling approaches based on the phase field crystal method and amplitude formalism, which can bridge mesoscopic and microscopic scales and incorporate system elasticity and plasticity, (ii) the study of nanostructure formation and dynamics during material heteroepitaxy, particularly for strained quantum dots modulated by nanoscale compositional patterns or eutectic microstructures, and (iii) the investigation of coupling mechanisms at meso and micro scales, for the coupling between morphological and compositional meso-scale instabilities and the coupling between meso and micro scales determining different growth modes. Comprehensive studies will be conducted numerically and analytically to identify various material growth mechanisms and the growth conditions for achieving controllable and coherent nanostructures, and predict new types of modulated structures in heteroepitaxial systems. The overall objective of this research is to advance our understanding of both structural and compositional dynamics in nonequilibrium and nanostructured material systems. This project also integrates the efforts of graduate and undergraduate education, and outreach activities designed for pre-service and in-service science teachers and their high-school students' science projects, to enhance K-12 science education for young women in Detroit who are underrepresented minority students.