GOALI/FRG: Epitaxial Growth of Perovskite Films and Heterostructures by Atomic Layer Deposition and Molecular Beam Epitaxy

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NON-TECHNICAL DESCRIPTION: The semiconductor industry is responsible for much of the world's extraordinary economic expansion over the past fifty years. Continuing the pace of growth and innovation will require new materials, such as crystalline perovskite films that are monolithically integrated with silicon, to be discovered, and efficient processes for their manufacture to be developed. These new material systems present an ideal platform to explore the fundamental materials physics and have numerous potential technology applications. This research develops a chemical route to the growth of these perovskite materials that will enable their insertion into technology applications in the commercial sector. The research combines an interdisciplinary team using a synergistic combination of epitaxial growth, ab initio theory, and in situ characterization as it develops a fundamental framework for growth of perovskite materials. The program partners university researchers with a technology leader in embedded semiconductors to broaden the student experience as they are exposed to problem definition that keeps the end goal of developing a viable technology front and center. The outreach program is aimed at attracting female high-school students to physical sciences and engineering; in collaboration with the physics instructors in local high schools, the students spend summers in research groups at the University of Texas at Austin and participate in "real science" in a supportive environment.TECHNICAL DETAILS: Monolithically integrated hybrid oxide/semiconductor systems employing crystalline perovskite layers present an ideal platform to explore the fundamental materials physics determining electronic and magnetic properties of multiferroic heterostructures, and when integrated with semiconductors, potentially have applications in advanced electronics, hyperspectral sensors, and persistent surveillance and radar technologies. Discovery of materials and their fundamental properties will rely on molecular beam epitaxy (MBE) growth of limited volumes of materials; however, chemical routes, such as atomic layer deposition (ALD) need to be explored in parallel to enable lower cost manufacturing routes, growth over large area substrates, and potentially easier insertion of multifunctional oxide technology applications into the commercial sector. The research develops a fundamental framework for the growth of homo- and heteroepitaxial perovskite films that is built on theory and experimental validation, develops chemical routes centered on ALD, and explores the defect nature of the films and interfaces through spectroscopic and diffraction techniques. The focus is on ALD; MBE is used to complement the samples grown by ALD and to prepare surfaces upon which to initiate ALD or follow the detailed steps in layer growth during ALD. Studies explore growth of SrTiO3, LaAlO3 and (Ba,Sr)TiO3 films and heterostructures. Students use an integrated facility that permits in situ growth by MBE and ALD, and in situ characterization using scanning probes, and electron, X-ray and photon spectroscopies.