CAREER: Atomic Processes in Low Temperature Molecular Beam Epitaxy of Diluted Magnetic III/V Compound Semiconductors

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

This CAREER project focuses on synthesis of dilute magnetic III/V compound semiconductors. These materials are expected to be used in next generation electronics-spintronics, where both the spin and charge properties of electrons perform functionality. This represents a major materi-als science challenge because incorporation of high concentrations of magnetic ions in host semi-conductors causes phase separation and destruction of material integrity. The approach to over-come this difficulty is utilization of low temperature molecular beam epitaxy. Using a combina-tion of epitaxial growth, in-situ and ex-situ measurements, direct correlation between atomic scale processes occurring during epitaxial growth and electronic/magnetic properties of the films will be investigated. Two candidate material systems, GaMnAs and GaMnN, will be examined. Epitaxial thin films will be grown by molecular beam epitaxy, and their physical properties di-rectly characterized in situ with atomic-scale precision by variable-temperature scanning tunnel-ing microscopy (STM), reflection high-energy electron diffraction and cross-sectional STM. In conjunction, structural, electrical and magnetic characteristics will be determined by ex situ tech-niques such as transmission electron microscopy, high-resolution x-ray diffraction, and magneto-transport measurement. A model of low temperature growth of diluted magnetic III/V compound semiconductors will then be developed. This may help to create new manufacturing methods that are compatible with existing compound semiconductor processing. This project also emphasizes the enhancement of educational experiences for students at both undergraduate and graduate levels. Substantial curriculum development for a new focus area in spintronics is proposed. Particularly, courses on the concepts and techniques of condensed matter at nanoscale will be developed. A sense of commitment to the education of the students also ex-tends to assisting them in finding a career where they can utilize their skills and knowledge ac-quired in school. New initiatives in industrial and educational outreach will be instituted. Spe-cifically, an industrial advisory and career committee will be formed to help foster industrially relevant activities and opportunities for students including internship and industrial research ex-periences. Outcomes of the educational effort of this project are expected to bring new concepts and techniques into the classroom and outstanding opportunities for students for future employ-ment in industry. %%% The project addresses fundamental research issues in a topical area of materials science having high technological relevance. The scope of the project will expose students to challenges in materials synthesis, processing, and characterization. An important feature of the project is the strong emphasis on education, and the integration of research and education. ***