CAREER: Surfactant-Mediated Epitaxy of Semiconductors on Insulators

点击翻译按钮获取中文摘要

This CAREER project addresses fundamental details epitaxy utilizing the surfactant effect in the epitaxial growth of silicon-germanium on crystalline calcium fluoride. The surfactant-an impurity overlayer that promotes epitaxy as it floats on the surface of the growing film-can be used to manipulate growth kinetics and access both compositions and morphologies that have not been previously achieved. The approach utilizes the group IV element Pb as the surfactant species; Pb as a surfactant can mediate epitaxial growth without degrading electronic properties of the semiconductor film due to its isoelectronic nature with respect to Si and Ge. Fundamental issues such as growth kinetics of semiconductors on epitaxial insulators and the role of isoelectronic surfactants, doping limits and dopant properties in ultra-thin, electrically isolated semiconductor films as well as three dimensional device integration will be studied. The growth of Ge and alloys made from Ge and Si are expected to uniquely enable the study of the effect of lattice mismatch induced strain on thin film synthesis and properties, both structural and electronic. Materials will be deposited by molecular beam epitaxy. Sample characterization will be carried out using a collection of complementary analysis techniques including atomic resolution transmission electron microscopy, atomic force microscopy, and variable temperature Hall effect. The proposed work has as its mission to understand and manipulate the processes involved in the epitaxial growth of highly dissimilar materials for the realization of novel quantum structures. The project expects to establish advanced synthesis capabilities that are well matched to a broad range of research activities on the Berkeley campus as well as local industries.%%%The project addresses fundamental research issues in electronic materials science having techno-logical relevance. Elements of this research will be integrated into a laboratory module on the materials science of thin-films and nanostructure synthesis. This module will be implemented as both part of a summer research program and as a culminating research experience in a senior-level capstone course in experimental materials science. In both cases, students will be involved in activities that will promote inquiry-based learning and information literacy and advancement through the levels of cognitive operations (Bloom's taxonomy). An electronic version, a virtual laboratory module, will be created to provide a research experience beyond the confines of the university campus, promoting scientific literacy in general to a broader audience. Successful exe-cution of the laboratory research module will encourage the development of research-based teaching innovations at a broader scale at the university. Integrated research-education activities are expected to stimulate the development of critical thinking skills of participants across a range of educational levels. Education activities will address interests of high school, community col-lege, and university students. Outreach efforts to increase the number of minority applicants to graduate school will also be carried out. ***